feat: remove retrieval batch over HTTP

README.md

@@ -19,13 +19,13 @@ wip-tui (interactive Worldspace explorer and operation editor)
 └── wip-protocol              descriptors and logical values
 
 wip-fs-server (request-time filesystem projection and loopback listener)
-├── wip-http                 standard routes/codecs/envelopes/batching
+├── wip-http                 standard routes/codecs/envelopes
 ├── wip-host                  request-scoped publication and dispatch
 └── wip-interface             macro-generated filesystem capabilities
 
 wip-public-api-example (workspace-only executable, integration tests, doctest)
 ├── wip-protocol              logical declarations, values, calls, and validation
-├── wip-http                 standard HTTP v1 routes, JSON codecs, envelopes, and batching
+├── wip-http                 standard HTTP v1 routes, JSON codecs, and envelopes
 │   └── wip-protocol
 ├── wip-client                stateful Known Space, lazy tree, observation, and call runtime
 │   ├── wip-http
@@ -41,13 +41,13 @@ wip-public-api-example (workspace-only executable, integration tests, doctest)
 | Crate | Responsibility | Does not own |
 | --- | --- | --- |
 | `wip-protocol` | Transport-independent descriptors, object/call/result types, logical `Value`s, validation, and stable protocol error categories. | Application DTOs, implementations, persistence, or wire encoding. |
-| `wip-http` | Standard WIP over HTTP v1 endpoint/route derivation, UTF-8 JSON codecs, direct success bodies, error/status classification, and retrieval batches. | HTTP I/O, URL scheme or TLS policy, authentication schemes, server frameworks, filesystem projection, or client presentation/cache policy. |
+| `wip-http` | Standard WIP over HTTP v1 endpoint/route derivation, UTF-8 JSON codecs, direct success bodies, and error/status classification. | HTTP I/O, URL scheme or TLS policy, authentication schemes, server frameworks, filesystem projection, or client presentation/cache policy. |
 | `wip-client` | Endpoint/security-context-isolated Known Space, normalized object and interface observations, intent-driven object and descriptor coverage with bounded request deduplication, immutable operation call contexts, stale transitions, and bounded histories. | HTTP I/O, credentials, persistent cache, automatic operation retries, or presentation widgets/events. |
 | `wip-tui` | Keyboard-only interactive Worldspace tree, selected Entry and qualified operation panes, descriptor-driven argument editing, bounded result/diagnostic rendering, terminal lifecycle, and HTTP I/O workers over `wip-client`. | Independent cache/validator semantics, automatic operation retries, Host internals, backend paths, or persistent state. |
 | `wip-interface` | The public `WipType`/`interface` authoring API, Rust-to-protocol codecs, generated descriptors, and typed implementation dispatch. | Object publication, backend lifetime, or transport policy. |
 | `wip-interface-macros` | Procedural-macro expansion used by `wip-interface`. It is not an application dependency. | A supported direct user API. |
 | `wip-host` | Opaque interface registration, explicit object membership, validator checks, interface-qualified dispatch against one host-owned instance, and descriptor-guided argument decoding inside that same resolution boundary. | Backend atomicity, global object lookup, or network serving. |
-| `wip-fs-server` | Linux directory-handle-confined request-time projection, complete depth-bounded observations and bounded file operations, standard `wip-http` dispatch/batch handling, and a loopback HTTP binary. | A new wire profile, implicit symlink following, non-loopback cleartext, authentication policy, TLS termination, or filesystem-wide preregistration. |
+| `wip-fs-server` | Linux directory-handle-confined request-time projection, complete depth-bounded observations and bounded file operations, standard `wip-http` dispatch, and a loopback HTTP binary. | A new wire profile, implicit symlink following, non-loopback cleartext, authentication policy, TLS termination, or filesystem-wide preregistration. |
 | `wip-public-api-example` | An independently compiled consumer of the protocol, authoring, and host public crates. Its DTOs and traits are application-owned; its implementation and backend handle remain host-private. | Reusable library API or a production server. |
 
 The boundary is intentional: protocol types describe what can cross a

crates/wip-client/tests/adapter.rs

@@ -16,7 +16,7 @@ use wip_protocol::{
 };
 
 fn limits() -> Limits {
-    Limits::new(64 * 1024, 64 * 1024, 64, 64).unwrap()
+    Limits::new(64 * 1024, 64 * 1024, 64).unwrap()
 }
 
 fn setup() -> (Client, wip_client::SessionId) {
@@ -145,16 +145,37 @@ fn valid_error_envelope_is_authoritative_and_status_mismatch_is_diagnostic() {
 }
 
 #[test]
-fn non_success_without_valid_envelope_remains_transport_failure() {
+fn resource_envelope_on_413_uses_code_and_records_canonical_422_mismatch() {
     let (mut client, session) = setup();
     let request = client.refresh_observed(&session, "/item", 0).unwrap();
-    let error = client
-        .complete(
-            request.id,
-            response(StatusCode::BAD_GATEWAY, b"gateway html"),
-        )
-        .unwrap_err();
-    assert_eq!(error.kind, ClientErrorKind::Transport);
+    let error = ProtocolError {
+        code: ProtocolErrorCode::ResourceLimitExceeded,
+        message: "logical observation limit exceeded".into(),
+    };
+    let mut encoded =
+        encode_protocol_error_response(ProtocolInteraction::Observe, &error, limits()).unwrap();
+    *encoded.status_mut() = StatusCode::PAYLOAD_TOO_LARGE;
+
+    assert_eq!(
+        client.complete(request.id, encoded).unwrap(),
+        Completion::ProtocolFailure(error)
+    );
+    assert_eq!(
+        client.diagnostics(&session).unwrap().back().unwrap().kind,
+        DiagnosticKind::HttpStatusMismatch
+    );
+}
+
+#[test]
+fn non_success_without_valid_envelope_remains_transport_failure() {
+    for status in [StatusCode::BAD_GATEWAY, StatusCode::PAYLOAD_TOO_LARGE] {
+        let (mut client, session) = setup();
+        let request = client.refresh_observed(&session, "/item", 0).unwrap();
+        let error = client
+            .complete(request.id, response(status, b"infrastructure failure"))
+            .unwrap_err();
+        assert_eq!(error.kind, ClientErrorKind::Transport);
+    }
 }
 
 #[test]
@@ -250,3 +271,80 @@ fn malformed_call_success_after_dispatch_is_outcome_unknown_and_stales_object()
     );
     assert_eq!(client.in_flight_len(), 0);
 }
+
+#[test]
+fn plain_413_after_call_dispatch_is_unknown_transport_outcome() {
+    let (mut client, session) = setup();
+    let observation = client.refresh_observed(&session, "/item", 0).unwrap();
+    client
+        .complete(
+            observation.id,
+            encode_observe_response(
+                &ObserveRequest {
+                    path: "/item".into(),
+                    depth: 0,
+                },
+                &ObjectObservation {
+                    object: object(),
+                    children: None,
+                },
+                limits(),
+            )
+            .unwrap(),
+        )
+        .unwrap();
+    let interface = client.prepare_interface(&session, "math").unwrap();
+    client
+        .complete(
+            interface.id,
+            encode_fetch_interface_response(
+                &FetchInterfaceRequest {
+                    interface: "math".into(),
+                },
+                &FetchInterfaceResponse {
+                    interface: "math".into(),
+                    descriptor: descriptor(INTERFACE_FORMAT_V1),
+                    validator: None,
+                },
+                limits(),
+            )
+            .unwrap(),
+        )
+        .unwrap();
+    let call = client
+        .prepare_call(
+            &session,
+            "/item",
+            "math",
+            "calculate",
+            BTreeMap::from([("value".into(), Value::Integer(2))]),
+        )
+        .unwrap();
+    client.mark_dispatched(call.id).unwrap();
+
+    let completion = client
+        .complete(
+            call.id,
+            Response::builder()
+                .status(StatusCode::PAYLOAD_TOO_LARGE)
+                .body(Vec::<u8>::new())
+                .unwrap(),
+        )
+        .unwrap();
+    assert!(matches!(
+        completion,
+        Completion::Call(record)
+            if matches!(
+                &record.outcome,
+                CallOutcome::Unknown {
+                    reason: OutcomeUnknownReason::ResponseDecode,
+                    failure: Some(failure),
+                } if failure.kind == ClientErrorKind::Transport
+            )
+    ));
+    assert_eq!(
+        client.object(&session, "/item").unwrap().state,
+        ObservationState::Stale
+    );
+    assert_eq!(client.in_flight_len(), 0);
+}

crates/wip-client/tests/runtime.rs

@@ -17,7 +17,7 @@ use wip_protocol::{
 };
 
 fn wire_limits() -> Limits {
-    Limits::new(64 * 1024, 64 * 1024, 64, 64).unwrap()
+    Limits::new(64 * 1024, 64 * 1024, 64).unwrap()
 }
 
 #[derive(Clone)]
@@ -399,6 +399,67 @@ fn ensure_interface_waits_for_request_and_cache_capacity_without_evicting() {
     ));
 }
 
+#[test]
+fn independent_retrievals_run_concurrently_and_complete_out_of_order() {
+    let mut client = client(8, 8, 8, 8);
+    let session = client
+        .open_session("https://example.test/wip", SecurityContext::new("subject"))
+        .unwrap();
+
+    let first = client.refresh_observed(&session, "/one", 0).unwrap();
+    let second = client.refresh_observed(&session, "/two", 0).unwrap();
+    let interface = client.prepare_interface(&session, "math").unwrap();
+
+    assert_eq!(first.request.uri().path(), "/wip/v1/observe");
+    assert_eq!(second.request.uri().path(), "/wip/v1/observe");
+    assert_eq!(interface.request.uri().path(), "/wip/v1/fetch_interface");
+    assert_eq!(client.in_flight_len(), 3);
+
+    client
+        .complete(
+            second.id,
+            observation_response("/two", &object("two", None, b"two")),
+        )
+        .unwrap();
+    client
+        .complete(
+            interface.id,
+            encode_fetch_interface_response(
+                &FetchInterfaceRequest {
+                    interface: "math".into(),
+                },
+                &FetchInterfaceResponse {
+                    interface: "math".into(),
+                    descriptor: descriptor(TypeExpr::Integer),
+                    validator: Some(b"math-v1".to_vec()),
+                },
+                wire_limits(),
+            )
+            .unwrap(),
+        )
+        .unwrap();
+    client
+        .complete(
+            first.id,
+            observation_response("/one", &object("one", None, b"one")),
+        )
+        .unwrap();
+
+    assert_eq!(
+        client.object(&session, "/one").unwrap().state,
+        ObservationState::Fresh
+    );
+    assert_eq!(
+        client.object(&session, "/two").unwrap().state,
+        ObservationState::Fresh
+    );
+    assert_eq!(
+        client.interface(&session, "math").unwrap().state,
+        ObservationState::Fresh
+    );
+    assert_eq!(client.in_flight_len(), 0);
+}
+
 #[test]
 fn newer_refresh_rejects_out_of_order_response_for_the_same_subject() {
     let mut client = client(8, 8, 8, 8);

crates/wip-fs-server/README.md

@@ -4,7 +4,7 @@
 Worldspace `/` at request time. It does not register the filesystem contents or
 keep one object instance per entry. It uses `wip-host` for publication and typed
 operation dispatch and uses the standard `wip-http` routes, JSON codecs,
-envelopes, batching, and HTTP status mapping.
+envelopes, and HTTP status mapping.
 
 ## Security model
 
@@ -118,14 +118,11 @@ curl -sS -X POST http://127.0.0.1:8080/wip/v1/call_operation \
   }'
 ```
 
-`observe` and `fetch_interface` can also be combined through the standard
-`POST /wip/v1/batch` route. `call_operation` is never batchable.
-
 ## Resource and failure behavior
 
 `ResourceLimits` bounds request/response bytes, HTTP request-head bytes, JSON
-nesting, batch items, file read/write bytes, tree depth/node count, pinned handles,
-and active connections/requests. One absolute request deadline covers header and
+nesting, file read/write bytes, tree depth/node count, pinned handles, and active
+connections/requests. One absolute request deadline covers header and
 body intake, dispatch, cooperative filesystem work, and response transmission;
 stalled clients are closed and cannot occupy a worker beyond that bound. Workers
 accept connections directly, so the listener never moves more than the configured

crates/wip-fs-server/src/lib.rs

@@ -4,7 +4,7 @@
 //!
 //! - [`wip_protocol`] owns logical requests and responses;
 //! - [`wip_host`] owns object publication, validators, and typed dispatch;
-//! - [`wip_http`] owns routes, JSON, envelopes, batching, and status mapping;
+//! - [`wip_http`] owns routes, JSON, envelopes, and status mapping;
 //! - this crate owns the filesystem capability boundary and the real HTTP listener.
 //!
 //! The built-in HTTP listener is intentionally loopback-only. TLS termination,
@@ -36,7 +36,7 @@ pub enum AccessMode {
 /// Bounded resource policy applied by the HTTP adapter and filesystem provider.
 #[derive(Debug, Clone, Copy)]
 pub struct ResourceLimits {
-    /// Standard JSON, body-size, nesting, and batch limits.
+    /// Standard JSON, body-size, and nesting limits.
     pub wire: wip_http::Limits,
     /// Maximum bytes returned by one file read.
     pub max_file_read_bytes: usize,
@@ -59,7 +59,7 @@ pub struct ResourceLimits {
 impl Default for ResourceLimits {
     fn default() -> Self {
         Self {
-            wire: wip_http::Limits::new(256 * 1024, 2 * 1024 * 1024, 64, 64)
+            wire: wip_http::Limits::new(256 * 1024, 2 * 1024 * 1024, 64)
                 .expect("default wire limits are nonzero"),
             max_file_read_bytes: 1024 * 1024,
             max_file_write_bytes: 1024 * 1024,

crates/wip-fs-server/src/server.rs

@@ -5,15 +5,14 @@ use std::sync::atomic::{AtomicBool, Ordering};
 use std::thread;
 use std::time::{Duration, Instant};
 
+use http::header::ALLOW;
 use http::{Request, Response, StatusCode};
 use wip_host::{ExecutionContext, ObjectProvider};
 use wip_http::{
-    BatchRequestKind, BatchResponse, BatchResponseItem, BatchSuccess, CodecError, EncodeHttpError,
-    Endpoint, RequestMetadataError, ResourceLimitKind, Route, decode_batch_request,
+    CodecError, EncodeHttpError, Endpoint, RequestMetadataError, Route,
     decode_call_operation_metadata, decode_fetch_interface_request, decode_observe_request,
-    encode_batch_error_response, encode_batch_resource_limit_error_response, encode_batch_response,
     encode_call_operation_response, encode_fetch_interface_response, encode_observe_response,
-    encode_protocol_error_response, encode_resource_limit_error_response, validate_http_request,
+    encode_protocol_error_response, validate_http_request,
 };
 use wip_protocol::{ProtocolError, ProtocolErrorCode, ProtocolInteraction};
 
@@ -68,20 +67,24 @@ impl WipFsServer {
         request: Request<Vec<u8>>,
         deadline: Instant,
     ) -> Response<Vec<u8>> {
-        let Some(route) = self.route(request.uri().path()) else {
+        let Some(route) = self.route(request.uri()) else {
             return empty_response(StatusCode::NOT_FOUND);
         };
         if let Err(error) = validate_http_request(&self.endpoint, route, &request) {
-            return self.metadata_error(route, error);
+            return self.metadata_error(error);
         }
         let context = ExecutionContext::new()
             .with_deadline(deadline)
             .with_resource_budget(u64::from(self.config.limits.max_observation_nodes));
-        match route {
+        let response = match route {
             Route::Observe => self.observe(request.body(), &context),
             Route::FetchInterface => self.fetch_interface(request.body()),
             Route::CallOperation => self.call_operation(request.body(), &context),
-            Route::Batch => self.batch(request.body(), &context),
+        };
+        if Instant::now() >= deadline {
+            empty_response(StatusCode::GATEWAY_TIMEOUT)
+        } else {
+            response
         }
     }
 
@@ -106,15 +109,13 @@ impl WipFsServer {
         })
     }
 
-    fn route(&self, path: &str) -> Option<Route> {
-        [
-            Route::Observe,
-            Route::FetchInterface,
-            Route::CallOperation,
-            Route::Batch,
-        ]
-        .into_iter()
-        .find(|route| self.endpoint.route(*route).path() == path)
+    fn route(&self, uri: &http::Uri) -> Option<Route> {
+        if uri.query().is_some() {
+            return None;
+        }
+        [Route::Observe, Route::FetchInterface, Route::CallOperation]
+            .into_iter()
+            .find(|route| self.endpoint.route(*route).path() == uri.path())
     }
 
     fn observe(&self, body: &[u8], context: &ExecutionContext) -> Response<Vec<u8>> {
@@ -127,7 +128,7 @@ impl WipFsServer {
                 .unwrap_or_else(|error| {
                     self.read_encode_error(ProtocolInteraction::Observe, error)
                 }),
-            Err(error) => self.protocol_error(ProtocolInteraction::Observe, &error, None),
+            Err(error) => self.protocol_error(ProtocolInteraction::Observe, &error),
         }
     }
 
@@ -143,7 +144,7 @@ impl WipFsServer {
                         self.read_encode_error(ProtocolInteraction::FetchInterface, error)
                     })
             }
-            Err(error) => self.protocol_error(ProtocolInteraction::FetchInterface, &error, None),
+            Err(error) => self.protocol_error(ProtocolInteraction::FetchInterface, &error),
         }
     }
 
@@ -181,7 +182,7 @@ impl WipFsServer {
                         },
                         message: "operation completed without response metadata".into(),
                     };
-                    return self.protocol_error(ProtocolInteraction::CallOperation, &error, None);
+                    return self.protocol_error(ProtocolInteraction::CallOperation, &error);
                 };
                 encode_call_operation_response(
                     &request,
@@ -190,6 +191,12 @@ impl WipFsServer {
                     self.config.limits.wire,
                 )
                 .unwrap_or_else(|encode_error| {
+                    if matches!(
+                        &encode_error,
+                        EncodeHttpError::Codec(codec) if is_transport_limit(codec)
+                    ) {
+                        return empty_response(StatusCode::INTERNAL_SERVER_ERROR);
+                    }
                     if !may_commit {
                         return self
                             .read_encode_error(ProtocolInteraction::CallOperation, encode_error);
@@ -200,58 +207,26 @@ impl WipFsServer {
                         code: ProtocolErrorCode::OperationOutcomeUnknown,
                         message: "operation completed but its response could not be encoded".into(),
                     };
-                    self.protocol_error(ProtocolInteraction::CallOperation, &error, None)
+                    self.protocol_error(ProtocolInteraction::CallOperation, &error)
                 })
             }
-            Err(error) => self.protocol_error(ProtocolInteraction::CallOperation, &error, None),
+            Err(error) => self.protocol_error(ProtocolInteraction::CallOperation, &error),
         }
     }
 
-    fn batch(&self, body: &[u8], context: &ExecutionContext) -> Response<Vec<u8>> {
-        let request = match decode_batch_request(body, self.config.limits.wire) {
-            Ok(request) => request,
-            Err(error) => return self.batch_codec_error(error),
-        };
-        let responses = request
-            .requests
-            .iter()
-            .map(|item| {
-                let outcome = match &item.request {
-                    BatchRequestKind::Observe(request) => self
-                        .projection
-                        .observe(context, request)
-                        .map(BatchSuccess::Observe),
-                    BatchRequestKind::FetchInterface(request) => self
-                        .projection
-                        .fetch_interface(request)
-                        .map(BatchSuccess::FetchInterface),
-                    BatchRequestKind::Invalid { error, .. } => Err(error.clone()),
-                };
-                BatchResponseItem {
-                    id: item.id.clone(),
-                    outcome,
-                }
-            })
-            .collect();
-        let response = BatchResponse { responses };
-        encode_batch_response(&request, &response, self.config.limits.wire).unwrap_or_else(
-            |error| match error {
-                EncodeHttpError::Codec(codec) => self.batch_codec_error(codec),
-                EncodeHttpError::Http(_) => self.batch_top_error(&internal_error(), None),
-            },
-        )
-    }
-
-    fn metadata_error(&self, route: Route, error: RequestMetadataError) -> Response<Vec<u8>> {
+    fn metadata_error(&self, error: RequestMetadataError) -> Response<Vec<u8>> {
         match error {
-            RequestMetadataError::InvalidRequest(_) => self.protocol_error(
-                interaction(route),
-                &ProtocolError {
-                    code: ProtocolErrorCode::InvalidRequest,
-                    message: "invalid HTTP request metadata".into(),
-                },
-                None,
-            ),
+            RequestMetadataError::NotFound => empty_response(StatusCode::NOT_FOUND),
+            error @ RequestMetadataError::MethodNotAllowed => Response::builder()
+                .status(error.status())
+                .header(
+                    ALLOW,
+                    error
+                        .allow()
+                        .expect("method-not-allowed metadata has an Allow value"),
+                )
+                .body(Vec::new())
+                .expect("static method response is valid"),
             RequestMetadataError::UnsupportedMediaType => {
                 empty_response(StatusCode::UNSUPPORTED_MEDIA_TYPE)
             }
@@ -264,8 +239,8 @@ impl WipFsServer {
         interaction: ProtocolInteraction,
         error: CodecError,
     ) -> Response<Vec<u8>> {
-        if let Some(kind) = error.resource_limit_kind() {
-            self.protocol_error(interaction, &resource_error(), Some(kind))
+        if is_transport_limit(&error) {
+            empty_response(StatusCode::PAYLOAD_TOO_LARGE)
         } else {
             self.protocol_error(
                 interaction,
@@ -273,21 +248,6 @@ impl WipFsServer {
                     code: ProtocolErrorCode::InvalidRequest,
                     message: "malformed WIP request".into(),
                 },
-                None,
-            )
-        }
-    }
-
-    fn batch_codec_error(&self, error: CodecError) -> Response<Vec<u8>> {
-        if let Some(kind) = error.resource_limit_kind() {
-            self.batch_top_error(&resource_error(), Some(kind))
-        } else {
-            self.batch_top_error(
-                &ProtocolError {
-                    code: ProtocolErrorCode::InvalidRequest,
-                    message: "malformed WIP batch request".into(),
-                },
-                None,
             )
         }
     }
@@ -298,10 +258,10 @@ impl WipFsServer {
         error: EncodeHttpError,
     ) -> Response<Vec<u8>> {
         match error {
-            EncodeHttpError::Codec(codec) if codec.resource_limit_kind().is_some() => {
-                self.protocol_error(interaction, &resource_error(), codec.resource_limit_kind())
+            EncodeHttpError::Codec(codec) if is_transport_limit(&codec) => {
+                empty_response(StatusCode::INTERNAL_SERVER_ERROR)
             }
-            _ => self.protocol_error(interaction, &internal_error(), None),
+            _ => self.protocol_error(interaction, &internal_error()),
         }
     }
 
@@ -309,32 +269,9 @@ impl WipFsServer {
         &self,
         interaction: ProtocolInteraction,
         error: &ProtocolError,
-        resource_kind: Option<ResourceLimitKind>,
     ) -> Response<Vec<u8>> {
-        let encoded = match resource_kind {
-            Some(kind) => encode_resource_limit_error_response(
-                interaction,
-                error,
-                kind,
-                self.config.limits.wire,
-            ),
-            None => encode_protocol_error_response(interaction, error, self.config.limits.wire),
-        };
-        encoded.unwrap_or_else(|_| empty_response(StatusCode::INTERNAL_SERVER_ERROR))
-    }
-
-    fn batch_top_error(
-        &self,
-        error: &ProtocolError,
-        resource_kind: Option<ResourceLimitKind>,
-    ) -> Response<Vec<u8>> {
-        let encoded = match resource_kind {
-            Some(kind) => {
-                encode_batch_resource_limit_error_response(error, kind, self.config.limits.wire)
-            }
-            None => encode_batch_error_response(error, self.config.limits.wire),
-        };
-        encoded.unwrap_or_else(|_| empty_response(StatusCode::INTERNAL_SERVER_ERROR))
+        encode_protocol_error_response(interaction, error, self.config.limits.wire)
+            .unwrap_or_else(|_| empty_response(StatusCode::INTERNAL_SERVER_ERROR))
     }
 }
 
@@ -404,7 +341,7 @@ struct ParsedRequestHead {
 enum IntakeError {
     Timeout,
     HeaderTooLarge,
-    PayloadTooLarge { target: String },
+    PayloadTooLarge,
     BadRequest,
     Socket,
 }
@@ -425,9 +362,7 @@ fn serve_connection(service: &WipFsServer, mut stream: TcpStream) {
         Err(IntakeError::HeaderTooLarge) => {
             Some(empty_response(StatusCode::REQUEST_HEADER_FIELDS_TOO_LARGE))
         }
-        Err(IntakeError::PayloadTooLarge { target }) => {
-            Some(payload_too_large_response(service, &target))
-        }
+        Err(IntakeError::PayloadTooLarge) => Some(empty_response(StatusCode::PAYLOAD_TOO_LARGE)),
         Err(IntakeError::BadRequest) => Some(empty_response(StatusCode::BAD_REQUEST)),
         Err(IntakeError::Timeout | IntakeError::Socket) => None,
     };
@@ -466,9 +401,7 @@ fn read_http_request(
 
     let parsed = parse_request_head(&received[..header_end])?;
     if parsed.content_length > maximum_body {
-        return Err(IntakeError::PayloadTooLarge {
-            target: parsed.target,
-        });
+        return Err(IntakeError::PayloadTooLarge);
     }
     let mut body = Vec::with_capacity(parsed.content_length);
     let buffered = &received[header_end..];
@@ -567,27 +500,6 @@ fn read_with_deadline(
     })
 }
 
-fn payload_too_large_response(service: &WipFsServer, target: &str) -> Response<Vec<u8>> {
-    let route = service.route(target.split('?').next().unwrap_or_default());
-    route.map_or_else(
-        || empty_response(StatusCode::PAYLOAD_TOO_LARGE),
-        |route| {
-            if route == Route::Batch {
-                service.batch_top_error(
-                    &resource_error(),
-                    Some(ResourceLimitKind::RepresentationBytes),
-                )
-            } else {
-                service.protocol_error(
-                    interaction(route),
-                    &resource_error(),
-                    Some(ResourceLimitKind::RepresentationBytes),
-                )
-            }
-        },
-    )
-}
-
 fn write_http_response(
     stream: &mut TcpStream,
     response: &Response<Vec<u8>>,
@@ -648,20 +560,11 @@ fn write_all_with_deadline(
     stream.flush()
 }
 
-fn interaction(route: Route) -> ProtocolInteraction {
-    match route {
-        Route::Observe => ProtocolInteraction::Observe,
-        Route::FetchInterface => ProtocolInteraction::FetchInterface,
-        Route::CallOperation => ProtocolInteraction::CallOperation,
-        Route::Batch => ProtocolInteraction::Observe,
-    }
-}
-
-fn resource_error() -> ProtocolError {
-    ProtocolError {
-        code: ProtocolErrorCode::ResourceLimitExceeded,
-        message: "configured resource limit exceeded".into(),
-    }
+fn is_transport_limit(error: &CodecError) -> bool {
+    matches!(
+        error,
+        CodecError::BodyTooLarge { .. } | CodecError::NestingTooDeep { .. }
+    )
 }
 
 fn internal_error() -> ProtocolError {

crates/wip-fs-server/tests/end_to_end.rs

@@ -9,10 +9,9 @@ use std::time::{Duration, Instant};
 use tempfile::tempdir;
 use wip_fs_server::{AccessMode, ServerConfig, WipFsServer};
 use wip_http::{
-    BatchRequest, BatchRequestItem, BatchRequestKind, BatchResponse, BatchSuccess, DecodedResponse,
-    Endpoint, JSON_CONTENT_TYPE, Limits, Route, decode_batch_request, decode_batch_response,
-    decode_call_operation_response, decode_fetch_interface_response, decode_observe_response,
-    encode_batch_request, encode_call_operation_request, encode_fetch_interface_request,
+    ClientResponseError, DecodedResponse, Endpoint, JSON_CONTENT_TYPE, Limits, Route,
+    TransportFailureKind, decode_call_operation_response, decode_fetch_interface_response,
+    decode_observe_response, encode_call_operation_request, encode_fetch_interface_request,
     encode_observe_request,
 };
 use wip_protocol::{
@@ -21,7 +20,7 @@ use wip_protocol::{
 };
 
 #[test]
-fn real_listener_serves_three_core_interactions_batch_and_write() {
+fn real_listener_serves_three_core_interactions_and_write() {
     let temporary = tempdir().expect("temporary root");
     std::fs::write(temporary.path().join("hello.txt"), b"hello world").expect("write file");
     std::fs::create_dir(temporary.path().join("nested")).expect("create directory");
@@ -124,36 +123,6 @@ fn real_listener_serves_three_core_interactions_batch_and_write() {
     );
     assert_eq!(read.result, Value::Bytes(b"world".to_vec()));
 
-    let batch_request = BatchRequest {
-        requests: vec![
-            BatchRequestItem {
-                id: "root".into(),
-                request: BatchRequestKind::Observe(ObserveRequest {
-                    path: "/".into(),
-                    depth: 0,
-                }),
-            },
-            BatchRequestItem {
-                id: "tree".into(),
-                request: BatchRequestKind::Observe(ObserveRequest {
-                    path: "/nested".into(),
-                    depth: 1,
-                }),
-            },
-            BatchRequestItem {
-                id: "interface".into(),
-                request: BatchRequestKind::FetchInterface(read_interface_request.clone()),
-            },
-        ],
-    };
-    let response = exchange(
-        address,
-        encode_batch_request(&endpoint, &batch_request, limits).expect("encode batch"),
-    );
-    let batch =
-        success(decode_batch_response(&batch_request, &response, limits).expect("decode batch"));
-    assert_batch_successes(&batch);
-
     let write_interface_request = FetchInterfaceRequest {
         interface: file.interfaces[1].clone(),
     };
@@ -210,6 +179,162 @@ fn real_listener_serves_three_core_interactions_batch_and_write() {
         .expect("listener exits cleanly");
 }
 
+#[test]
+fn real_listener_keeps_route_method_and_malformed_body_boundaries_distinct() {
+    let temporary = tempdir().expect("temporary root");
+    let mut config = ServerConfig::for_root(temporary.path());
+    config.limits.wire = Limits::new(64, 4_096, 64).expect("wire limits");
+    let bound = Arc::new(
+        WipFsServer::new(config)
+            .expect("build server")
+            .bind()
+            .expect("bind"),
+    );
+    let address = bound.local_addr();
+    let shutdown = Arc::new(AtomicBool::new(false));
+    let worker = {
+        let bound = Arc::clone(&bound);
+        let shutdown = Arc::clone(&shutdown);
+        thread::spawn(move || bound.serve_until(shutdown))
+    };
+
+    for uri in [
+        "/wip/v1/unknown",
+        "/wip/v1/batch",
+        "/wip/v1/observe?unexpected=true",
+        "/wip/v1/observe/extra",
+    ] {
+        let response = exchange(address, json_request(http::Method::POST, uri, b"{}"));
+        assert_eq!(response.status(), http::StatusCode::NOT_FOUND);
+        assert!(response.body().is_empty());
+        assert!(!response.headers().contains_key(http::header::CONTENT_TYPE));
+        assert!(!response.headers().contains_key(http::header::ALLOW));
+    }
+
+    let wrong_method = exchange(
+        address,
+        json_request(http::Method::GET, "/wip/v1/observe", b""),
+    );
+    assert_eq!(wrong_method.status(), http::StatusCode::METHOD_NOT_ALLOWED);
+    assert_eq!(wrong_method.headers()[http::header::ALLOW], "POST");
+    assert!(wrong_method.body().is_empty());
+    assert!(
+        !wrong_method
+            .headers()
+            .contains_key(http::header::CONTENT_TYPE)
+    );
+
+    let mut unsupported_coding = json_request(
+        http::Method::POST,
+        "/wip/v1/observe",
+        br#"{"path":"/","depth":0}"#,
+    );
+    unsupported_coding
+        .headers_mut()
+        .insert(http::header::CONTENT_ENCODING, "gzip".parse().unwrap());
+    let unsupported_coding = exchange(address, unsupported_coding);
+    assert_eq!(
+        unsupported_coding.status(),
+        http::StatusCode::UNSUPPORTED_MEDIA_TYPE
+    );
+    assert!(unsupported_coding.body().is_empty());
+    assert!(
+        !unsupported_coding
+            .headers()
+            .contains_key(http::header::CONTENT_TYPE)
+    );
+
+    let malformed = exchange(
+        address,
+        json_request(http::Method::POST, "/wip/v1/observe", b"{"),
+    );
+    assert_eq!(malformed.status(), http::StatusCode::BAD_REQUEST);
+    assert_eq!(
+        malformed.headers()[http::header::CONTENT_TYPE],
+        JSON_CONTENT_TYPE
+    );
+    assert!(
+        std::str::from_utf8(malformed.body())
+            .expect("UTF-8 error envelope")
+            .contains("\"invalid_request\"")
+    );
+
+    let oversized = exchange(
+        address,
+        json_request(http::Method::POST, "/wip/v1/observe", &[b'x'; 65]),
+    );
+    assert_eq!(oversized.status(), http::StatusCode::PAYLOAD_TOO_LARGE);
+    assert!(oversized.body().is_empty());
+    assert!(!oversized.headers().contains_key(http::header::CONTENT_TYPE));
+
+    let mut header_only = TcpStream::connect(address).expect("connect header-only client");
+    header_only
+        .set_read_timeout(Some(Duration::from_secs(1)))
+        .expect("set header-only timeout");
+    write!(
+        header_only,
+        "POST /wip/v1/observe HTTP/1.1\r\nHost: localhost\r\nContent-Type: application/json\r\nContent-Length: 65\r\n\r\n"
+    )
+    .expect("write oversized request head");
+    header_only.flush().expect("flush oversized request head");
+    let mut raw = Vec::new();
+    header_only
+        .read_to_end(&mut raw)
+        .expect("read immediate limit response");
+    assert!(raw.starts_with(b"HTTP/1.1 413 "));
+    assert!(raw.ends_with(b"\r\n\r\n"));
+    assert!(
+        !raw.windows(b"resource_limit_exceeded".len())
+            .any(|window| { window == b"resource_limit_exceeded" })
+    );
+
+    shutdown.store(true, Ordering::Release);
+    worker
+        .join()
+        .expect("join listener")
+        .expect("listener exits cleanly");
+}
+
+#[test]
+fn raw_decoder_limits_are_transport_failures() {
+    let temporary = tempdir().expect("temporary root");
+    let mut config = ServerConfig::for_root(temporary.path());
+    config.limits.wire = Limits::new(4_096, 4_096, 8).expect("wire limits");
+    let server = WipFsServer::new(config).expect("build server");
+
+    let nested = br#"{"path":[[[[[[[[["/"]]]]]]]]],"depth":0}"#;
+    let response = server.handle_http(json_request(http::Method::POST, "/wip/v1/observe", nested));
+    assert_eq!(response.status(), http::StatusCode::PAYLOAD_TOO_LARGE);
+    assert!(response.body().is_empty());
+    assert!(!response.headers().contains_key(http::header::CONTENT_TYPE));
+}
+
+#[test]
+fn logical_observation_limit_remains_protocol_resource_failure() {
+    let temporary = tempdir().expect("temporary root");
+    let mut config = ServerConfig::for_root(temporary.path());
+    config.limits.max_observation_depth = 0;
+    let limits = config.limits.wire;
+    let server = WipFsServer::new(config).expect("build server");
+    let endpoint = Endpoint::parse("http://localhost/wip").expect("endpoint");
+    let request = ObserveRequest {
+        path: "/".into(),
+        depth: 1,
+    };
+
+    let response = server.handle_http(
+        encode_observe_request(&endpoint, &request, limits).expect("encode observation"),
+    );
+    assert_eq!(response.status(), http::StatusCode::UNPROCESSABLE_ENTITY);
+    assert!(matches!(
+        decode_observe_response(&request, &response, limits).expect("decode logical limit"),
+        DecodedResponse::ProtocolFailure {
+            error,
+            status_mismatch: None,
+        } if error.code == ProtocolErrorCode::ResourceLimitExceeded
+    ));
+}
+
 #[test]
 fn stalled_request_body_times_out_and_releases_the_only_worker() {
     let temporary = tempdir().expect("temporary root");
@@ -281,37 +406,6 @@ fn stalled_request_body_times_out_and_releases_the_only_worker() {
         .expect("listener exits cleanly");
 }
 
-#[test]
-fn batch_keeps_known_malformed_arguments_item_local() {
-    let temporary = tempdir().expect("temporary root");
-    let config = ServerConfig::for_root(temporary.path());
-    let limits = config.limits.wire;
-    let server = WipFsServer::new(config).expect("build server");
-    let endpoint = Endpoint::parse("http://localhost/wip").expect("endpoint");
-    let body = br#"{"requests":[{"id":"ok","method":"observe","arguments":{"path":"/","depth":0}},{"id":"bad","method":"observe","arguments":{"path":"/","depth":"bad"}}]}"#;
-    let logical = decode_batch_request(body, limits).expect("decode item-local invalid request");
-    assert!(matches!(
-        logical.requests[1].request,
-        BatchRequestKind::Invalid { .. }
-    ));
-    let request = http::Request::builder()
-        .method(http::Method::POST)
-        .uri(endpoint.route(Route::Batch).as_str())
-        .header(http::header::CONTENT_TYPE, JSON_CONTENT_TYPE)
-        .header(http::header::ACCEPT, "application/json")
-        .body(body.to_vec())
-        .expect("build request");
-    let response = server.handle_http(request);
-    let batch = success(
-        decode_batch_response(&logical, &response, limits).expect("decode mixed batch response"),
-    );
-    assert!(matches!(
-        batch.responses[0].outcome,
-        Ok(BatchSuccess::Observe(_))
-    ));
-    assert!(batch.responses[1].outcome.is_err());
-}
-
 #[test]
 fn call_argument_decoding_does_not_mask_missing_target() {
     let temporary = tempdir().expect("temporary root");
@@ -359,11 +453,11 @@ fn backend_invalid_unicode_path_is_not_found_not_internal() {
 }
 
 #[test]
-fn read_response_size_failure_preserves_non_commit_guarantee() {
+fn read_response_size_failure_is_transport_local() {
     let temporary = tempdir().expect("temporary root");
     std::fs::write(temporary.path().join("large"), vec![b'x'; 2_000]).expect("write file");
     let mut config = ServerConfig::for_root(temporary.path());
-    config.limits.wire = Limits::new(4_096, 1_024, 64, 64).expect("wire limits");
+    config.limits.wire = Limits::new(4_096, 1_024, 64).expect("wire limits");
     let limits = config.limits.wire;
     let server = WipFsServer::new(config).expect("build server");
     let endpoint = Endpoint::parse("http://localhost/wip").expect("endpoint");
@@ -406,30 +500,15 @@ fn read_response_size_failure_preserves_non_commit_guarantee() {
         encode_call_operation_request(&endpoint, &call, &interface.descriptor, limits)
             .expect("encode read call"),
     );
-    assert_eq!(response.status(), http::StatusCode::PAYLOAD_TOO_LARGE);
-    match decode_call_operation_response(&call, &interface.descriptor, &response, limits)
-        .expect("decode resource failure")
-    {
-        DecodedResponse::ProtocolFailure { error, .. } => {
-            assert_eq!(error.code, ProtocolErrorCode::ResourceLimitExceeded);
-        }
-        DecodedResponse::Success(_) => panic!("oversized read response must fail"),
-    }
-}
-
-fn assert_batch_successes(batch: &BatchResponse) {
-    assert_eq!(batch.responses.len(), 3);
+    assert_eq!(response.status(), http::StatusCode::INTERNAL_SERVER_ERROR);
+    assert!(response.body().is_empty());
+    assert!(!response.headers().contains_key(http::header::CONTENT_TYPE));
     assert!(matches!(
-        batch.responses[0].outcome,
-        Ok(BatchSuccess::Observe(_))
-    ));
-    assert!(matches!(
-        batch.responses[1].outcome,
-        Ok(BatchSuccess::Observe(_))
-    ));
-    assert!(matches!(
-        batch.responses[2].outcome,
-        Ok(BatchSuccess::FetchInterface(_))
+        decode_call_operation_response(&call, &interface.descriptor, &response, limits)
+            .expect_err("oversized representation is not a protocol failure"),
+        ClientResponseError::TransportBinding(failure)
+            if failure.status == http::StatusCode::INTERNAL_SERVER_ERROR
+                && failure.kind == TransportFailureKind::HttpStatus
     ));
 }
 
@@ -440,6 +519,16 @@ fn success<T>(response: DecodedResponse<T>) -> T {
     }
 }
 
+fn json_request(method: http::Method, uri: &str, body: &[u8]) -> http::Request<Vec<u8>> {
+    http::Request::builder()
+        .method(method)
+        .uri(uri)
+        .header(http::header::CONTENT_TYPE, JSON_CONTENT_TYPE)
+        .header(http::header::ACCEPT, "application/json")
+        .body(body.to_vec())
+        .expect("build JSON request")
+}
+
 fn exchange(address: SocketAddr, request: http::Request<Vec<u8>>) -> http::Response<Vec<u8>> {
     let mut stream = TcpStream::connect(address).expect("connect listener");
     stream

crates/wip-http/src/batch.rs

@@ -1,570 +0,0 @@
-use std::collections::{BTreeMap, BTreeSet};
-
-use http::header::{ACCEPT, CONTENT_TYPE};
-use http::{Method, Request, Response, StatusCode};
-use serde_json::{Map, Value as Json};
-use wip_protocol::{
-    FetchInterfaceRequest, FetchInterfaceResponse, INTERFACE_FORMAT_V1, ObserveRequest,
-    ObserveResponse, ProtocolError, ProtocolErrorCode, ProtocolInteraction,
-};
-
-use crate::response::{self, DecodedResponse};
-use crate::{
-    BodyKind, ClientResponseError, CodecError, EncodeHttpError, Endpoint, InvalidResponseKind,
-    JSON_CONTENT_TYPE, Limits, ResourceLimitKind, Route, is_json_content_type, json,
-};
-
-/// A retrieval method accepted by the standard v1 batch endpoint.
-#[derive(Debug, Clone, Copy, PartialEq, Eq)]
-pub enum BatchMethod {
-    /// Observe one object and its indexable descendants.
-    Observe,
-    /// Fetch one interface descriptor.
-    FetchInterface,
-}
-
-impl BatchMethod {
-    fn name(self) -> &'static str {
-        match self {
-            Self::Observe => "observe",
-            Self::FetchInterface => "fetch_interface",
-        }
-    }
-
-    fn interaction(self) -> ProtocolInteraction {
-        match self {
-            Self::Observe => ProtocolInteraction::Observe,
-            Self::FetchInterface => ProtocolInteraction::FetchInterface,
-        }
-    }
-}
-
-/// One retrieval interaction accepted by the standard v1 batch endpoint.
-#[derive(Debug, Clone, PartialEq, Eq)]
-pub enum BatchRequestKind {
-    /// Observe one object and its indexable descendants.
-    Observe(ObserveRequest),
-    /// Fetch one interface descriptor.
-    FetchInterface(FetchInterfaceRequest),
-    /// A known method whose `arguments` are not a valid logical request.
-    Invalid {
-        /// Method that was successfully identified from the item envelope.
-        method: BatchMethod,
-        /// Item-local `invalid_request` to return without rejecting other items.
-        error: ProtocolError,
-    },
-}
-
-impl BatchRequestKind {
-    fn interaction(&self) -> ProtocolInteraction {
-        match self {
-            Self::Observe(_) => ProtocolInteraction::Observe,
-            Self::FetchInterface(_) => ProtocolInteraction::FetchInterface,
-            Self::Invalid { method, .. } => method.interaction(),
-        }
-    }
-}
-
-/// One uniquely identified batch subrequest.
-#[derive(Debug, Clone, PartialEq, Eq)]
-pub struct BatchRequestItem {
-    /// Identifier used only to correlate the corresponding subresponse.
-    pub id: String,
-    /// Retrieval interaction and arguments.
-    pub request: BatchRequestKind,
-}
-
-/// A standard v1 batch request.
-#[derive(Debug, Clone, PartialEq, Eq)]
-pub struct BatchRequest {
-    /// Independent subrequests. Identifiers must be unique.
-    pub requests: Vec<BatchRequestItem>,
-}
-
-/// Successful result of one batch item.
-#[derive(Debug, Clone, PartialEq)]
-pub enum BatchSuccess {
-    /// Successful `observe` result.
-    Observe(ObserveResponse),
-    /// Successful `fetch_interface` result.
-    FetchInterface(FetchInterfaceResponse),
-}
-
-/// One batch subresponse, correlated by `id` rather than array position.
-#[derive(Debug, Clone, PartialEq)]
-pub struct BatchResponseItem {
-    /// Identifier copied from its subrequest.
-    pub id: String,
-    /// Direct interaction result or canonical item-local protocol failure.
-    pub outcome: Result<BatchSuccess, ProtocolError>,
-}
-
-/// A valid standard v1 batch response.
-#[derive(Debug, Clone, PartialEq)]
-pub struct BatchResponse {
-    /// Exactly one response for each requested identifier, in any order.
-    pub responses: Vec<BatchResponseItem>,
-}
-
-fn validate_ids<'a>(ids: impl Iterator<Item = &'a str>, maximum: usize) -> Result<(), CodecError> {
-    let mut seen = BTreeSet::new();
-    let mut count = 0;
-    for id in ids {
-        count += 1;
-        if !seen.insert(id) {
-            return Err(CodecError::DuplicateBatchId { id: id.into() });
-        }
-    }
-    if count > maximum {
-        return Err(CodecError::TooManyBatchItems {
-            actual: count,
-            maximum,
-        });
-    }
-    Ok(())
-}
-
-fn request_item_to_json(item: &BatchRequestItem) -> Result<Json, CodecError> {
-    let (method, arguments) = match &item.request {
-        BatchRequestKind::Observe(value) => ("observe", json::observe_request_to_json(value)),
-        BatchRequestKind::FetchInterface(value) => (
-            "fetch_interface",
-            json::fetch_interface_request_to_json(value),
-        ),
-        BatchRequestKind::Invalid { .. } => {
-            return Err(CodecError::InvalidField {
-                field: "requests".into(),
-                reason: "item-local invalid requests cannot be encoded as client requests".into(),
-            });
-        }
-    };
-    Ok(serde_json::json!({"id": item.id, "method": method, "arguments": arguments}))
-}
-
-fn request_to_json(request: &BatchRequest, limits: Limits) -> Result<Json, CodecError> {
-    validate_ids(
-        request.requests.iter().map(|item| item.id.as_str()),
-        limits.max_batch_items,
-    )?;
-    for item in &request.requests {
-        match &item.request {
-            BatchRequestKind::Observe(value) => value.validate()?,
-            BatchRequestKind::FetchInterface(_) | BatchRequestKind::Invalid { .. } => {}
-        }
-    }
-    let requests = request
-        .requests
-        .iter()
-        .map(request_item_to_json)
-        .collect::<Result<Vec<_>, _>>()?;
-    Ok(serde_json::json!({"requests": requests}))
-}
-
-fn request_from_json(value: &Json, limits: Limits) -> Result<BatchRequest, CodecError> {
-    let fields = exact_object(value, "batch", &["requests"])?;
-    let values = array(required(fields, "requests")?, "requests")?;
-    if values.len() > limits.max_batch_items {
-        return Err(CodecError::TooManyBatchItems {
-            actual: values.len(),
-            maximum: limits.max_batch_items,
-        });
-    }
-    let mut requests = Vec::with_capacity(values.len());
-    for (index, value) in values.iter().enumerate() {
-        let field = format!("requests[{index}]");
-        let fields = exact_object(value, &field, &["id", "method", "arguments"])?;
-        let id = string(required(fields, "id")?, &format!("{field}.id"))?;
-        let method_name = string(required(fields, "method")?, &format!("{field}.method"))?;
-        let arguments = required(fields, "arguments")?;
-        let method = match method_name.as_str() {
-            "observe" => BatchMethod::Observe,
-            "fetch_interface" => BatchMethod::FetchInterface,
-            _ => {
-                return Err(CodecError::InvalidField {
-                    field: format!("{field}.method"),
-                    reason: "batch supports only observe and fetch_interface".into(),
-                });
-            }
-        };
-        let decoded = match method {
-            BatchMethod::Observe => {
-                json::observe_request_from_json(arguments).map(BatchRequestKind::Observe)
-            }
-            BatchMethod::FetchInterface => json::fetch_interface_request_from_json(arguments)
-                .map(BatchRequestKind::FetchInterface),
-        };
-        let request = decoded.unwrap_or_else(|error| BatchRequestKind::Invalid {
-            method,
-            error: ProtocolError {
-                code: ProtocolErrorCode::InvalidRequest,
-                message: format!("invalid {} arguments: {error}", method.name()),
-            },
-        });
-        requests.push(BatchRequestItem { id, request });
-    }
-    validate_ids(
-        requests.iter().map(|item| item.id.as_str()),
-        limits.max_batch_items,
-    )?;
-    Ok(BatchRequest { requests })
-}
-
-/// Encodes a batch request using `POST v1/batch`.
-pub fn encode_batch_request(
-    endpoint: &Endpoint,
-    value: &BatchRequest,
-    limits: Limits,
-) -> Result<Request<Vec<u8>>, EncodeHttpError> {
-    let body = json::serialize(&request_to_json(value, limits)?, BodyKind::Request, limits)?;
-    Ok(Request::builder()
-        .method(Method::POST)
-        .uri(endpoint.route(Route::Batch).as_str())
-        .header(CONTENT_TYPE, JSON_CONTENT_TYPE)
-        .header(ACCEPT, "application/json")
-        .body(body)?)
-}
-
-/// Decodes and validates a batch request body.
-pub fn decode_batch_request(body: &[u8], limits: Limits) -> Result<BatchRequest, CodecError> {
-    let value = json::parse(body, BodyKind::Request, limits)?;
-    request_from_json(&value, limits)
-}
-
-fn success_to_json(success: &BatchSuccess) -> Json {
-    match success {
-        BatchSuccess::Observe(value) => json::observe_response_to_json(value),
-        BatchSuccess::FetchInterface(value) => json::fetch_interface_response_to_json(value),
-    }
-}
-
-fn response_to_json(
-    request: &BatchRequest,
-    response: &BatchResponse,
-    limits: Limits,
-) -> Result<Json, CodecError> {
-    correlate(request, response, limits)?;
-    Ok(serde_json::json!({
-        "responses": response.responses.iter().map(|item| {
-            let mut fields = Map::new();
-            fields.insert("id".into(), Json::String(item.id.clone()));
-            match &item.outcome {
-                Ok(success) => { fields.insert("result".into(), success_to_json(success)); }
-                Err(error) => { fields.insert("error".into(), response::item_error_to_json(error)); }
-            }
-            Json::Object(fields)
-        }).collect::<Vec<_>>()
-    }))
-}
-
-fn correlate(
-    request: &BatchRequest,
-    response: &BatchResponse,
-    limits: Limits,
-) -> Result<(), CodecError> {
-    validate_ids(
-        request.requests.iter().map(|item| item.id.as_str()),
-        limits.max_batch_items,
-    )?;
-    validate_ids(
-        response.responses.iter().map(|item| item.id.as_str()),
-        limits.max_batch_items,
-    )?;
-    let requested: BTreeMap<&str, &BatchRequestKind> = request
-        .requests
-        .iter()
-        .map(|item| (item.id.as_str(), &item.request))
-        .collect();
-    for item in &response.responses {
-        let Some(kind) = requested.get(item.id.as_str()) else {
-            return Err(CodecError::UnexpectedBatchId {
-                id: item.id.clone(),
-            });
-        };
-        match (&item.outcome, *kind) {
-            (Ok(BatchSuccess::Observe(value)), BatchRequestKind::Observe(request)) => {
-                request.validate_response(value)?;
-            }
-            (
-                Ok(BatchSuccess::FetchInterface(value)),
-                BatchRequestKind::FetchInterface(request),
-            ) => {
-                value.validate_for(request)?;
-            }
-            (
-                Err(error),
-                BatchRequestKind::Invalid {
-                    error: expected, ..
-                },
-            ) if error == expected => {}
-            (Err(error), kind)
-                if !matches!(kind, BatchRequestKind::Invalid { .. })
-                    && error.code.is_allowed_for(kind.interaction()) => {}
-            _ => {
-                return Err(CodecError::BatchInteractionMismatch {
-                    id: item.id.clone(),
-                });
-            }
-        }
-    }
-    for item in &request.requests {
-        if !response.responses.iter().any(|other| other.id == item.id) {
-            return Err(CodecError::MissingBatchId {
-                id: item.id.clone(),
-            });
-        }
-    }
-    Ok(())
-}
-
-/// Encodes a valid batch response. Item failures remain inside HTTP 200.
-pub fn encode_batch_response(
-    request: &BatchRequest,
-    value: &BatchResponse,
-    limits: Limits,
-) -> Result<Response<Vec<u8>>, EncodeHttpError> {
-    let body = json::serialize(
-        &response_to_json(request, value, limits)?,
-        BodyKind::Response,
-        limits,
-    )?;
-    Ok(Response::builder()
-        .status(StatusCode::OK)
-        .header(CONTENT_TYPE, JSON_CONTENT_TYPE)
-        .body(body)?)
-}
-
-/// Encodes a top-level batch-envelope failure.
-///
-/// Item-local failures belong in [`BatchResponseItem`]. Only failures that can
-/// reject the batch envelope before item execution are accepted here. A
-/// resource-limit failure defaults to the logical-limit status; use
-/// [`encode_batch_resource_limit_error_response`] when the concrete class is
-/// known.
-pub fn encode_batch_error_response(
-    error: &ProtocolError,
-    limits: Limits,
-) -> Result<Response<Vec<u8>>, EncodeHttpError> {
-    if !matches!(
-        error.code,
-        ProtocolErrorCode::InvalidRequest
-            | ProtocolErrorCode::ResourceLimitExceeded
-            | ProtocolErrorCode::Internal
-    ) {
-        return Err(CodecError::InvalidField {
-            field: "error.code".into(),
-            reason: "code is not valid for a top-level batch failure".into(),
-        }
-        .into());
-    }
-    let body = json::serialize(&response::error_to_json(error), BodyKind::Response, limits)?;
-    Ok(Response::builder()
-        .status(response::status_for_error(error.code))
-        .header(CONTENT_TYPE, JSON_CONTENT_TYPE)
-        .body(body)?)
-}
-
-/// Encodes a class-specific top-level batch `resource_limit_exceeded` failure.
-pub fn encode_batch_resource_limit_error_response(
-    error: &ProtocolError,
-    kind: ResourceLimitKind,
-    limits: Limits,
-) -> Result<Response<Vec<u8>>, EncodeHttpError> {
-    if error.code != ProtocolErrorCode::ResourceLimitExceeded {
-        return Err(CodecError::InvalidField {
-            field: "error.code".into(),
-            reason: "resource-limit encoder requires resource_limit_exceeded".into(),
-        }
-        .into());
-    }
-    let body = json::serialize(&response::error_to_json(error), BodyKind::Response, limits)?;
-    Ok(Response::builder()
-        .status(response::status_for_resource_limit(kind))
-        .header(CONTENT_TYPE, JSON_CONTENT_TYPE)
-        .body(body)?)
-}
-
-fn response_from_json(
-    value: &Json,
-    request: &BatchRequest,
-    limits: Limits,
-) -> Result<BatchResponse, CodecError> {
-    let fields = exact_object(value, "batch", &["responses"])?;
-    let values = array(required(fields, "responses")?, "responses")?;
-    if values.len() > limits.max_batch_items {
-        return Err(CodecError::TooManyBatchItems {
-            actual: values.len(),
-            maximum: limits.max_batch_items,
-        });
-    }
-    let requested: BTreeMap<&str, &BatchRequestKind> = request
-        .requests
-        .iter()
-        .map(|item| (item.id.as_str(), &item.request))
-        .collect();
-    let mut responses = Vec::with_capacity(values.len());
-    for (index, value) in values.iter().enumerate() {
-        let field = format!("responses[{index}]");
-        let fields = object(value, &field)?;
-        for name in fields.keys() {
-            if !["id", "result", "error"].contains(&name.as_str()) {
-                return Err(CodecError::UnknownField {
-                    field: format!("{field}.{name}"),
-                });
-            }
-        }
-        let id = string(required(fields, "id")?, &format!("{field}.id"))?;
-        let Some(kind) = requested.get(id.as_str()) else {
-            return Err(CodecError::UnexpectedBatchId { id });
-        };
-        let outcome = match (fields.get("result"), fields.get("error")) {
-            (Some(_), Some(_)) | (None, None) => {
-                return Err(CodecError::InvalidField {
-                    field,
-                    reason: "batch item must contain exactly one of result or error".into(),
-                });
-            }
-            (None, Some(error)) => {
-                let error = response::item_error_from_json(error)?;
-                match kind {
-                    BatchRequestKind::Invalid {
-                        error: expected, ..
-                    } if error == *expected => {}
-                    BatchRequestKind::Invalid { .. } => {
-                        return Err(CodecError::BatchInteractionMismatch { id });
-                    }
-                    kind if error.code.is_allowed_for(kind.interaction()) => {}
-                    _ => return Err(CodecError::BatchInteractionMismatch { id }),
-                }
-                Err(error)
-            }
-            (Some(result), None) => Ok(match kind {
-                BatchRequestKind::Observe(request) => {
-                    let value = json::observe_response_from_json(result)?;
-                    request.validate_response(&value)?;
-                    BatchSuccess::Observe(value)
-                }
-                BatchRequestKind::FetchInterface(request) => {
-                    let value = json::fetch_interface_response_from_json(result)?;
-                    value.validate_for(request)?;
-                    BatchSuccess::FetchInterface(value)
-                }
-                BatchRequestKind::Invalid { .. } => {
-                    return Err(CodecError::BatchInteractionMismatch { id });
-                }
-            }),
-        };
-        responses.push(BatchResponseItem { id, outcome });
-    }
-    let response = BatchResponse { responses };
-    correlate(request, &response, limits)?;
-    Ok(response)
-}
-
-/// Decodes a batch response, including item-local failures within HTTP 200.
-pub fn decode_batch_response<B: AsRef<[u8]>>(
-    request: &BatchRequest,
-    value: &Response<B>,
-    limits: Limits,
-) -> Result<DecodedResponse<BatchResponse>, ClientResponseError> {
-    let valid_content_type = value
-        .headers()
-        .get(CONTENT_TYPE)
-        .and_then(|value| value.to_str().ok())
-        .is_some_and(is_json_content_type);
-    if !valid_content_type {
-        if value.status().is_success() {
-            return Err(ClientResponseError::invalid(
-                InvalidResponseKind::InvalidBatch,
-                "missing or non-UTF-8 application/json Content-Type",
-            ));
-        }
-        return Err(response::transport_failure(value.status()));
-    }
-    let decoded = response::decode(
-        value.status(),
-        value.body().as_ref(),
-        ProtocolInteraction::Observe,
-        limits,
-        |json| response_from_json(json, request, limits),
-    )
-    .map_err(|error| match error {
-        ClientResponseError::InvalidResponse { detail, .. } => {
-            ClientResponseError::invalid(InvalidResponseKind::InvalidBatch, detail)
-        }
-        other => other,
-    })?;
-    if let DecodedResponse::ProtocolFailure { error, .. } = &decoded
-        && !matches!(
-            error.code,
-            ProtocolErrorCode::InvalidRequest
-                | ProtocolErrorCode::ResourceLimitExceeded
-                | ProtocolErrorCode::Internal
-        )
-    {
-        return Err(ClientResponseError::invalid(
-            InvalidResponseKind::InvalidBatch,
-            "protocol code is not valid for a top-level batch failure",
-        ));
-    }
-    if let DecodedResponse::Success(success) = &decoded {
-        for item in &success.responses {
-            if let Ok(BatchSuccess::FetchInterface(interface)) = &item.outcome
-                && interface.descriptor.format != INTERFACE_FORMAT_V1
-            {
-                return Err(ClientResponseError::UnsupportedDescriptorFormat {
-                    format: interface.descriptor.format.clone(),
-                });
-            }
-        }
-    }
-    Ok(decoded)
-}
-
-fn object<'a>(value: &'a Json, field: &str) -> Result<&'a Map<String, Json>, CodecError> {
-    value.as_object().ok_or_else(|| CodecError::InvalidField {
-        field: field.into(),
-        reason: "expected object".into(),
-    })
-}
-
-fn exact_object<'a>(
-    value: &'a Json,
-    field: &str,
-    allowed: &[&str],
-) -> Result<&'a Map<String, Json>, CodecError> {
-    let fields = object(value, field)?;
-    for name in fields.keys() {
-        if !allowed.contains(&name.as_str()) {
-            return Err(CodecError::UnknownField {
-                field: format!("{field}.{name}"),
-            });
-        }
-    }
-    Ok(fields)
-}
-
-fn required<'a>(fields: &'a Map<String, Json>, name: &str) -> Result<&'a Json, CodecError> {
-    fields
-        .get(name)
-        .ok_or_else(|| CodecError::MissingField { field: name.into() })
-}
-
-fn string(value: &Json, field: &str) -> Result<String, CodecError> {
-    value
-        .as_str()
-        .map(str::to_owned)
-        .ok_or_else(|| CodecError::InvalidField {
-            field: field.into(),
-            reason: "expected string".into(),
-        })
-}
-
-fn array<'a>(value: &'a Json, field: &str) -> Result<&'a [Json], CodecError> {
-    value
-        .as_array()
-        .map(Vec::as_slice)
-        .ok_or_else(|| CodecError::InvalidField {
-            field: field.into(),
-            reason: "expected array".into(),
-        })
-}

crates/wip-http/src/codec.rs

@@ -1,7 +1,7 @@
 use std::error::Error;
 use std::fmt::{self, Display, Formatter};
 
-use http::header::{ACCEPT, CONTENT_TYPE};
+use http::header::{ACCEPT, CONTENT_ENCODING, CONTENT_TYPE};
 use http::{HeaderMap, Method, Request, Response, StatusCode};
 use wip_protocol::{
     CallOperationRequest, CallOperationResponse, FetchInterfaceRequest, FetchInterfaceResponse,
@@ -12,7 +12,7 @@ use wip_protocol::{
 use crate::response::{self, DecodedResponse};
 use crate::{
     BodyKind, ClientResponseError, CodecError, Endpoint, InvalidResponseKind, JSON_CONTENT_TYPE,
-    Limits, ResourceLimitKind, Route, json,
+    Limits, Route, json,
 };
 
 fn request(
@@ -36,6 +36,9 @@ fn response(status: StatusCode, body: Vec<u8>) -> Result<Response<Vec<u8>>, http
 }
 
 fn require_response_content_type<B>(response: &Response<B>) -> Result<(), ClientResponseError> {
+    if !has_supported_content_coding(response.headers()) {
+        return Err(response::unsupported_content_coding(response.status()));
+    }
     let valid = response
         .headers()
         .get(CONTENT_TYPE)
@@ -181,9 +184,11 @@ fn accepts_json(headers: &HeaderMap) -> bool {
 /// A failure while validating inbound HTTP request metadata.
 #[derive(Debug)]
 pub enum RequestMetadataError {
-    /// The method or route does not match the selected WIP interaction.
-    InvalidRequest(CodecError),
-    /// The request body does not use UTF-8 `application/json`.
+    /// The request URI does not exactly identify the selected standard route.
+    NotFound,
+    /// A known standard route was requested with a method other than `POST`.
+    MethodNotAllowed,
+    /// The request body does not use UTF-8 `application/json` or identity coding.
     UnsupportedMediaType,
     /// The request's `Accept` metadata excludes `application/json`.
     NotAcceptable,
@@ -194,32 +199,47 @@ impl RequestMetadataError {
     #[must_use]
     pub const fn status(&self) -> StatusCode {
         match self {
-            Self::InvalidRequest(_) => StatusCode::BAD_REQUEST,
+            Self::NotFound => StatusCode::NOT_FOUND,
+            Self::MethodNotAllowed => StatusCode::METHOD_NOT_ALLOWED,
             Self::UnsupportedMediaType => StatusCode::UNSUPPORTED_MEDIA_TYPE,
             Self::NotAcceptable => StatusCode::NOT_ACCEPTABLE,
         }
     }
+
+    /// Returns the value for an `Allow` response header, when required.
+    #[must_use]
+    pub const fn allow(&self) -> Option<&'static str> {
+        match self {
+            Self::MethodNotAllowed => Some("POST"),
+            Self::NotFound | Self::UnsupportedMediaType | Self::NotAcceptable => None,
+        }
+    }
 }
 
 impl Display for RequestMetadataError {
     fn fmt(&self, formatter: &mut Formatter<'_>) -> fmt::Result {
         match self {
-            Self::InvalidRequest(error) => error.fmt(formatter),
+            Self::NotFound => formatter.write_str("request URI is not a standard WIP route"),
+            Self::MethodNotAllowed => formatter.write_str("standard WIP routes require POST"),
             Self::UnsupportedMediaType => {
-                formatter.write_str("expected UTF-8 application/json Content-Type")
+                formatter.write_str("expected identity-coded UTF-8 application/json Content-Type")
             }
             Self::NotAcceptable => formatter.write_str("request does not accept application/json"),
         }
     }
 }
 
-impl Error for RequestMetadataError {
-    fn source(&self) -> Option<&(dyn Error + 'static)> {
-        match self {
-            Self::InvalidRequest(error) => Some(error),
-            Self::UnsupportedMediaType | Self::NotAcceptable => None,
-        }
-    }
+impl Error for RequestMetadataError {}
+
+pub(crate) fn has_supported_content_coding(headers: &HeaderMap) -> bool {
+    headers.get_all(CONTENT_ENCODING).iter().all(|value| {
+        value.to_str().is_ok_and(|value| {
+            let mut codings = value.split(',').map(str::trim);
+            let first = codings.next();
+            first.is_some_and(|coding| coding.eq_ignore_ascii_case("identity"))
+                && codings.all(|coding| coding.eq_ignore_ascii_case("identity"))
+        })
+    })
 }
 
 /// Validates mandatory HTTP metadata for an inbound WIP request.
@@ -233,29 +253,19 @@ pub fn validate_http_request<B>(
     route: Route,
     value: &Request<B>,
 ) -> Result<(), RequestMetadataError> {
-    if value.method() != Method::POST {
-        return Err(RequestMetadataError::InvalidRequest(
-            CodecError::InvalidField {
-                field: "method".into(),
-                reason: "standard WIP routes require POST".into(),
-            },
-        ));
-    }
     let expected = endpoint.route(route);
     if value.uri().path() != expected.path() || value.uri().query().is_some() {
-        return Err(RequestMetadataError::InvalidRequest(
-            CodecError::InvalidField {
-                field: "route".into(),
-                reason: "request URI does not match the selected standard route".into(),
-            },
-        ));
+        return Err(RequestMetadataError::NotFound);
+    }
+    if value.method() != Method::POST {
+        return Err(RequestMetadataError::MethodNotAllowed);
     }
     let valid_content_type = value
         .headers()
         .get(CONTENT_TYPE)
         .and_then(|value| value.to_str().ok())
         .is_some_and(is_json_content_type);
-    if !valid_content_type {
+    if !valid_content_type || !has_supported_content_coding(value.headers()) {
         return Err(RequestMetadataError::UnsupportedMediaType);
     }
     if !accepts_json(value.headers()) {
@@ -526,9 +536,8 @@ fn encode_protocol_error_with_status(
 /// The code must be allowed for `interaction`. This API accepts only
 /// [`ProtocolError`], so client-local `InvalidResponse` and
 /// `UnsupportedDescriptorFormat` classifications cannot be emitted as Host
-/// error envelopes. Resource-limit errors use the logical-limit status; callers
-/// that know the concrete limit class should use
-/// [`encode_resource_limit_error_response`].
+/// error envelopes. Logical `resource_limit_exceeded` failures use HTTP 422;
+/// representation and deployment limits are not protocol errors.
 pub fn encode_protocol_error_response(
     interaction: ProtocolInteraction,
     error: &ProtocolError,
@@ -542,28 +551,6 @@ pub fn encode_protocol_error_response(
     )
 }
 
-/// Encodes a `resource_limit_exceeded` envelope with its class-specific status.
-pub fn encode_resource_limit_error_response(
-    interaction: ProtocolInteraction,
-    error: &ProtocolError,
-    kind: ResourceLimitKind,
-    limits: Limits,
-) -> Result<Response<Vec<u8>>, EncodeHttpError> {
-    if error.code != wip_protocol::ProtocolErrorCode::ResourceLimitExceeded {
-        return Err(CodecError::InvalidField {
-            field: "error.code".into(),
-            reason: "resource-limit encoder requires resource_limit_exceeded".into(),
-        }
-        .into());
-    }
-    encode_protocol_error_with_status(
-        interaction,
-        error,
-        response::status_for_resource_limit(kind),
-        limits,
-    )
-}
-
 /// Failure while building an outbound framework-neutral HTTP message.
 #[derive(Debug)]
 pub enum EncodeHttpError {

crates/wip-http/src/endpoint.rs

@@ -15,8 +15,6 @@ pub enum Route {
     FetchInterface,
     /// Call one operation.
     CallOperation,
-    /// Package independent retrieval interactions.
-    Batch,
 }
 
 impl Route {
@@ -27,7 +25,6 @@ impl Route {
             Self::Observe => "v1/observe",
             Self::FetchInterface => "v1/fetch_interface",
             Self::CallOperation => "v1/call_operation",
-            Self::Batch => "v1/batch",
         }
     }
 }
@@ -82,12 +79,7 @@ impl Endpoint {
     /// are not route components and therefore never match.
     #[must_use]
     pub fn recognize(&self, candidate: &Url) -> Option<Route> {
-        const ROUTES: [Route; 4] = [
-            Route::Observe,
-            Route::FetchInterface,
-            Route::CallOperation,
-            Route::Batch,
-        ];
+        const ROUTES: [Route; 3] = [Route::Observe, Route::FetchInterface, Route::CallOperation];
         if candidate.query().is_some() || candidate.fragment().is_some() {
             return None;
         }

crates/wip-http/src/error.rs

@@ -10,8 +10,6 @@ pub struct Limits {
     pub(crate) max_response_bytes: usize,
     /// Largest accepted JSON container nesting depth.
     pub(crate) max_nesting: usize,
-    /// Largest accepted number of batch items.
-    pub(crate) max_batch_items: usize,
 }
 
 impl Limits {
@@ -20,7 +18,6 @@ impl Limits {
         max_request_bytes: usize,
         max_response_bytes: usize,
         max_nesting: usize,
-        max_batch_items: usize,
     ) -> Result<Self, LimitConfigurationError> {
         if max_request_bytes == 0 {
             return Err(LimitConfigurationError::ZeroRequestBytes);
@@ -31,14 +28,10 @@ impl Limits {
         if max_nesting == 0 {
             return Err(LimitConfigurationError::ZeroNesting);
         }
-        if max_batch_items == 0 {
-            return Err(LimitConfigurationError::ZeroBatchItems);
-        }
         Ok(Self {
             max_request_bytes,
             max_response_bytes,
             max_nesting,
-            max_batch_items,
         })
     }
 
@@ -59,12 +52,6 @@ impl Limits {
     pub const fn max_nesting(self) -> usize {
         self.max_nesting
     }
-
-    /// Returns the batch item count limit.
-    #[must_use]
-    pub const fn max_batch_items(self) -> usize {
-        self.max_batch_items
-    }
 }
 
 /// Why a [`Limits`] configuration is not bounded.
@@ -76,8 +63,6 @@ pub enum LimitConfigurationError {
     ZeroResponseBytes,
     /// Nesting limit was zero.
     ZeroNesting,
-    /// Batch-item limit was zero.
-    ZeroBatchItems,
 }
 
 impl Display for LimitConfigurationError {
@@ -86,7 +71,6 @@ impl Display for LimitConfigurationError {
             Self::ZeroRequestBytes => "request byte limit must be nonzero",
             Self::ZeroResponseBytes => "response byte limit must be nonzero",
             Self::ZeroNesting => "nesting limit must be nonzero",
-            Self::ZeroBatchItems => "batch item limit must be nonzero",
         })
     }
 }
@@ -102,15 +86,6 @@ pub enum BodyKind {
     Response,
 }
 
-/// The class of a resource limit exceeded by a wire representation.
-#[derive(Debug, Clone, Copy, PartialEq, Eq)]
-pub enum ResourceLimitKind {
-    /// A request or response representation exceeded its byte-size limit.
-    RepresentationBytes,
-    /// A logical limit such as nesting depth, batch count, or collection size was exceeded.
-    Logical,
-}
-
 /// A malformed or locally disallowed wire representation.
 #[derive(Debug)]
 pub enum CodecError {
@@ -157,47 +132,6 @@ pub enum CodecError {
     },
     /// Logical protocol validation rejected the decoded representation.
     ProtocolValidation(wip_protocol::ValidationError),
-    /// The batch exceeds its configured item count.
-    TooManyBatchItems {
-        /// Actual item count.
-        actual: usize,
-        /// Configured maximum.
-        maximum: usize,
-    },
-    /// Batch item identifiers are not unique.
-    DuplicateBatchId {
-        /// Repeated identifier.
-        id: String,
-    },
-    /// A response contains a batch identifier that was not requested.
-    UnexpectedBatchId {
-        /// Unexpected identifier.
-        id: String,
-    },
-    /// A response omitted a requested batch identifier.
-    MissingBatchId {
-        /// Missing identifier.
-        id: String,
-    },
-    /// A batch item result does not match its requested interaction.
-    BatchInteractionMismatch {
-        /// Item identifier.
-        id: String,
-    },
-}
-
-impl CodecError {
-    /// Classifies this failure when it represents a canonical resource limit.
-    #[must_use]
-    pub const fn resource_limit_kind(&self) -> Option<ResourceLimitKind> {
-        match self {
-            Self::BodyTooLarge { .. } => Some(ResourceLimitKind::RepresentationBytes),
-            Self::NestingTooDeep { .. } | Self::TooManyBatchItems { .. } => {
-                Some(ResourceLimitKind::Logical)
-            }
-            _ => None,
-        }
-    }
 }
 
 impl Display for CodecError {
@@ -225,15 +159,6 @@ impl Display for CodecError {
                 write!(formatter, "field `{field}` is not canonical base64")
             }
             Self::ProtocolValidation(error) => error.fmt(formatter),
-            Self::TooManyBatchItems { actual, maximum } => {
-                write!(formatter, "batch has {actual} items; maximum is {maximum}")
-            }
-            Self::DuplicateBatchId { id } => write!(formatter, "duplicate batch id `{id}`"),
-            Self::UnexpectedBatchId { id } => write!(formatter, "unexpected batch id `{id}`"),
-            Self::MissingBatchId { id } => write!(formatter, "missing batch id `{id}`"),
-            Self::BatchInteractionMismatch { id } => {
-                write!(formatter, "batch result does not match request `{id}`")
-            }
         }
     }
 }

crates/wip-http/src/lib.rs

@@ -2,11 +2,11 @@
 //!
 //! This crate owns endpoint and route derivation, UTF-8 JSON encoding, canonical
 //! success and error response handling, HTTP status mapping, descriptor-guided
-//! operation-value conversion, and retrieval batching. It deliberately performs
-//! no I/O and depends on no server framework, TLS implementation, filesystem
-//! projection, client cache, or presentation layer. URL schemes, TLS,
-//! certificates, authentication mechanisms, proxies, and caches are selected by
-//! the HTTP implementation and deployment rather than by WIP conformance.
+//! operation-value conversion. It deliberately performs no I/O and depends on no
+//! server framework, TLS implementation, filesystem projection, client cache, or
+//! presentation layer. URL schemes, TLS, certificates, authentication mechanisms,
+//! proxies, and caches are selected by the HTTP implementation and deployment
+//! rather than by WIP conformance.
 //!
 //! Logical values remain owned by [`wip_protocol`]. Validators and `Bytes` are
 //! encoded in JSON bodies using canonical RFC 4648 Section 4 base64; this crate
@@ -17,7 +17,7 @@
 //! use wip_protocol::ObserveRequest;
 //!
 //! let endpoint = Endpoint::parse("http://example.test/api/wip")?;
-//! let limits = Limits::new(64 * 1024, 1024 * 1024, 64, 100)?;
+//! let limits = Limits::new(64 * 1024, 1024 * 1024, 64)?;
 //! let request = encode_observe_request(
 //!     &endpoint,
 //!     &ObserveRequest { path: "/items/123".into(), depth: 0 },
@@ -30,34 +30,25 @@
 
 #![deny(missing_docs)]
 
-mod batch;
 mod codec;
 mod endpoint;
 mod error;
 mod json;
 mod response;
 
-pub use batch::{
-    BatchMethod, BatchRequest, BatchRequestItem, BatchRequestKind, BatchResponse,
-    BatchResponseItem, BatchSuccess, decode_batch_request, decode_batch_response,
-    encode_batch_error_response, encode_batch_request, encode_batch_resource_limit_error_response,
-    encode_batch_response,
-};
 pub use codec::{
     CallOperationMetadata, EncodeHttpError, RequestMetadataError, decode_call_operation_metadata,
     decode_call_operation_request, decode_call_operation_response, decode_fetch_interface_request,
     decode_fetch_interface_response, decode_observe_request, decode_observe_response,
     encode_call_operation_request, encode_call_operation_response, encode_fetch_interface_request,
     encode_fetch_interface_response, encode_observe_request, encode_observe_response,
-    encode_protocol_error_response, encode_resource_limit_error_response, is_json_content_type,
-    validate_http_request,
+    encode_protocol_error_response, is_json_content_type, validate_http_request,
 };
 pub use endpoint::{Endpoint, EndpointError, JSON_CONTENT_TYPE, Route};
-pub use error::{BodyKind, CodecError, LimitConfigurationError, Limits, ResourceLimitKind};
+pub use error::{BodyKind, CodecError, LimitConfigurationError, Limits};
 pub use response::{
     ClientResponseError, DecodedResponse, InvalidResponseKind, StatusMismatch,
     TransportBindingFailure, TransportFailureKind, error_code_name, status_for_error,
-    status_for_resource_limit,
 };
 
 /// Framework-neutral HTTP types used by this binding's public API.

crates/wip-http/src/response.rs

@@ -5,7 +5,7 @@ use http::StatusCode;
 use serde_json::{Map, Value as Json};
 use wip_protocol::{ProtocolError, ProtocolErrorCode, ProtocolInteraction};
 
-use crate::{BodyKind, CodecError, Limits, ResourceLimitKind, json};
+use crate::{BodyKind, CodecError, Limits, json};
 
 /// A successfully classified client response.
 #[derive(Debug, Clone, PartialEq, Eq)]
@@ -37,6 +37,8 @@ pub enum TransportFailureKind {
     AuthenticationRequired,
     /// HTTP 403, commonly emitted by endpoint policy or infrastructure.
     EndpointForbidden,
+    /// The response uses a content coding the client does not support.
+    UnsupportedContentCoding,
     /// Another non-success HTTP response without a WIP error envelope.
     HttpStatus,
 }
@@ -63,8 +65,6 @@ pub enum InvalidResponseKind {
     NonCanonicalSuccessStatus,
     /// A 2xx body was malformed or semantically invalid.
     InvalidSuccessBody,
-    /// A batch response did not correlate exactly with its request.
-    InvalidBatch,
 }
 
 /// A local failure while classifying or validating a peer response.
@@ -119,10 +119,6 @@ impl Display for ClientResponseError {
 impl Error for ClientResponseError {}
 
 /// Returns the canonical HTTP status for a wire-level protocol error.
-///
-/// [`ProtocolErrorCode::ResourceLimitExceeded`] defaults to the logical-limit
-/// status. Use [`status_for_resource_limit`] when the concrete limit class is
-/// known.
 #[must_use]
 pub const fn status_for_error(code: ProtocolErrorCode) -> StatusCode {
     match code {
@@ -145,22 +141,8 @@ pub const fn status_for_error(code: ProtocolErrorCode) -> StatusCode {
     }
 }
 
-/// Returns the canonical HTTP status for a concrete resource-limit class.
-#[must_use]
-pub const fn status_for_resource_limit(kind: ResourceLimitKind) -> StatusCode {
-    match kind {
-        ResourceLimitKind::RepresentationBytes => StatusCode::PAYLOAD_TOO_LARGE,
-        ResourceLimitKind::Logical => StatusCode::UNPROCESSABLE_ENTITY,
-    }
-}
-
 fn status_matches_error(status: StatusCode, code: ProtocolErrorCode) -> bool {
-    match code {
-        ProtocolErrorCode::ResourceLimitExceeded => {
-            status == StatusCode::PAYLOAD_TOO_LARGE || status == StatusCode::UNPROCESSABLE_ENTITY
-        }
-        _ => status == status_for_error(code),
-    }
+    status == status_for_error(code)
 }
 
 /// Returns the stable snake-case wire spelling of a protocol code.
@@ -213,14 +195,7 @@ pub(crate) fn error_to_json(error: &ProtocolError) -> Json {
     })
 }
 
-pub(crate) fn item_error_to_json(error: &ProtocolError) -> Json {
-    serde_json::json!({
-        "code": error_code_name(error.code),
-        "message": error.message,
-    })
-}
-
-pub(crate) fn item_error_from_json(value: &Json) -> Result<ProtocolError, CodecError> {
+fn protocol_error_from_json(value: &Json) -> Result<ProtocolError, CodecError> {
     let fields = value
         .as_object()
         .ok_or_else(|| invalid_field("error", "expected object"))?;
@@ -239,7 +214,7 @@ fn envelope_error_from_json(value: &Json) -> Result<Option<ProtocolError>, Codec
     if fields.len() != 1 || !fields.contains_key("error") {
         return Ok(None);
     }
-    item_error_from_json(&fields["error"]).map(Some)
+    protocol_error_from_json(&fields["error"]).map(Some)
 }
 
 fn exact(fields: &Map<String, Json>, allowed: &[&str], parent: &str) -> Result<(), CodecError> {
@@ -355,6 +330,13 @@ pub(crate) fn decode<T>(
     }
 }
 
+pub(crate) fn unsupported_content_coding(status: StatusCode) -> ClientResponseError {
+    ClientResponseError::TransportBinding(TransportBindingFailure {
+        status,
+        kind: TransportFailureKind::UnsupportedContentCoding,
+    })
+}
+
 pub(crate) fn transport_failure(status: StatusCode) -> ClientResponseError {
     let kind = match status {
         StatusCode::UNAUTHORIZED => TransportFailureKind::AuthenticationRequired,

crates/wip-http/tests/batch.rs

@@ -1,345 +0,0 @@
-use wip_http::http::StatusCode;
-use wip_http::wip_protocol::{
-    FetchInterfaceRequest, FetchInterfaceResponse, INTERFACE_FORMAT_V1, InterfaceDescriptor,
-    Object, ObjectObservation, ObserveRequest, ProtocolError, ProtocolErrorCode,
-};
-use wip_http::{
-    BatchMethod, BatchRequest, BatchRequestItem, BatchRequestKind, BatchResponse,
-    BatchResponseItem, BatchSuccess, ClientResponseError, DecodedResponse, Endpoint,
-    InvalidResponseKind, Limits, ResourceLimitKind, decode_batch_request, decode_batch_response,
-    encode_batch_error_response, encode_batch_request, encode_batch_resource_limit_error_response,
-    encode_batch_response,
-};
-
-fn limits() -> Limits {
-    Limits::new(100_000, 100_000, 64, 4).unwrap()
-}
-
-fn observed_item(validator: Option<Vec<u8>>) -> ObjectObservation {
-    ObjectObservation {
-        object: Object {
-            name: "item".into(),
-            description: None,
-            interfaces: vec![],
-            r#ref: None,
-            validator,
-        },
-        children: None,
-    }
-}
-
-fn request() -> BatchRequest {
-    BatchRequest {
-        requests: vec![
-            BatchRequestItem {
-                id: "object".into(),
-                request: BatchRequestKind::Observe(ObserveRequest {
-                    path: "/item".into(),
-                    depth: 0,
-                }),
-            },
-            BatchRequestItem {
-                id: "interface".into(),
-                request: BatchRequestKind::FetchInterface(FetchInterfaceRequest {
-                    interface: "interface-v1".into(),
-                }),
-            },
-        ],
-    }
-}
-
-#[test]
-fn batch_round_trips_by_unique_id_with_item_failures_and_validators() {
-    let request = request();
-    let endpoint = Endpoint::parse("https://example.test/wip").unwrap();
-    let encoded_request = encode_batch_request(&endpoint, &request, limits()).unwrap();
-    assert_eq!(encoded_request.uri().path(), "/wip/v1/batch");
-    assert_eq!(encoded_request.headers()["accept"], "application/json");
-    assert_eq!(
-        decode_batch_request(encoded_request.body(), limits()).unwrap(),
-        request
-    );
-
-    let response = BatchResponse {
-        responses: vec![
-            BatchResponseItem {
-                id: "interface".into(),
-                outcome: Err(ProtocolError {
-                    code: ProtocolErrorCode::InterfaceNotFound,
-                    message: "gone".into(),
-                }),
-            },
-            BatchResponseItem {
-                id: "object".into(),
-                outcome: Ok(BatchSuccess::Observe(observed_item(Some(vec![
-                    0, 1, 2, 255,
-                ])))),
-            },
-        ],
-    };
-    let encoded = encode_batch_response(&request, &response, limits()).unwrap();
-    assert_eq!(encoded.status(), StatusCode::OK);
-    assert!(
-        std::str::from_utf8(encoded.body())
-            .unwrap()
-            .contains("AAEC/w==")
-    );
-    assert_eq!(
-        decode_batch_response(&request, &encoded, limits()).unwrap(),
-        DecodedResponse::Success(response)
-    );
-}
-
-#[test]
-fn batch_interface_validator_round_trips_in_item_body() {
-    let request = BatchRequest {
-        requests: vec![BatchRequestItem {
-            id: "interface".into(),
-            request: BatchRequestKind::FetchInterface(FetchInterfaceRequest {
-                interface: "interface-v1".into(),
-            }),
-        }],
-    };
-    let response = BatchResponse {
-        responses: vec![BatchResponseItem {
-            id: "interface".into(),
-            outcome: Ok(BatchSuccess::FetchInterface(FetchInterfaceResponse {
-                interface: "interface-v1".into(),
-                descriptor: InterfaceDescriptor {
-                    format: INTERFACE_FORMAT_V1.into(),
-                    documentation: None,
-                    types: vec![],
-                    operations: vec![],
-                },
-                validator: Some(vec![255, 254, 253]),
-            })),
-        }],
-    };
-    let encoded = encode_batch_response(&request, &response, limits()).unwrap();
-    assert!(
-        std::str::from_utf8(encoded.body())
-            .unwrap()
-            .contains("//79")
-    );
-    assert_eq!(
-        decode_batch_response(&request, &encoded, limits()).unwrap(),
-        DecodedResponse::Success(response)
-    );
-}
-
-#[test]
-fn malformed_known_method_arguments_are_item_local() {
-    let body = br#"{
-        "requests": [
-            {"id":"valid","method":"observe","arguments":{"path":"/item","depth":0}},
-            {"id":"invalid","method":"observe","arguments":{"path":"/","depth":"deep"}}
-        ]
-    }"#;
-    let decoded = decode_batch_request(body, limits()).unwrap();
-    assert!(matches!(
-        decoded.requests[0].request,
-        BatchRequestKind::Observe(_)
-    ));
-    let invalid = match &decoded.requests[1].request {
-        BatchRequestKind::Invalid { method, error } => {
-            assert_eq!(*method, BatchMethod::Observe);
-            assert_eq!(error.code, ProtocolErrorCode::InvalidRequest);
-            error.clone()
-        }
-        other => panic!("expected item-local invalid request, got {other:?}"),
-    };
-
-    let response = BatchResponse {
-        responses: vec![
-            BatchResponseItem {
-                id: "valid".into(),
-                outcome: Ok(BatchSuccess::Observe(observed_item(None))),
-            },
-            BatchResponseItem {
-                id: "invalid".into(),
-                outcome: Err(invalid),
-            },
-        ],
-    };
-    let encoded = encode_batch_response(&decoded, &response, limits()).unwrap();
-    assert_eq!(encoded.status(), StatusCode::OK);
-    assert_eq!(
-        decode_batch_response(&decoded, &encoded, limits()).unwrap(),
-        DecodedResponse::Success(response)
-    );
-}
-
-#[test]
-fn invalid_batch_envelopes_are_rejected_at_top_level() {
-    assert!(decode_batch_request(br#"{}"#, limits()).is_err());
-
-    let malformed_item = br#"{
-        "requests": [
-            {"id":"item","method":"observe","arguments":{"path":"/","depth":0},"extra":true}
-        ]
-    }"#;
-    assert!(decode_batch_request(malformed_item, limits()).is_err());
-
-    let duplicate = br#"{
-        "requests": [
-            {"id":"same","method":"observe","arguments":{"path":"/a","depth":0}},
-            {"id":"same","method":"observe","arguments":{"path":"/b","depth":0}}
-        ]
-    }"#;
-    assert!(decode_batch_request(duplicate, limits()).is_err());
-
-    let operation = br#"{
-        "requests": [
-            {"id":"call","method":"call_operation","arguments":{}}
-        ]
-    }"#;
-    assert!(decode_batch_request(operation, limits()).is_err());
-
-    let too_many = Limits::new(100_000, 100_000, 64, 1).unwrap();
-    assert!(decode_batch_request(duplicate, too_many).is_err());
-}
-
-#[test]
-fn batch_resource_limits_use_413_or_422_and_never_429() {
-    let error = ProtocolError {
-        code: ProtocolErrorCode::ResourceLimitExceeded,
-        message: "bounded".into(),
-    };
-    for (kind, status) in [
-        (
-            ResourceLimitKind::RepresentationBytes,
-            StatusCode::PAYLOAD_TOO_LARGE,
-        ),
-        (ResourceLimitKind::Logical, StatusCode::UNPROCESSABLE_ENTITY),
-    ] {
-        let encoded = encode_batch_resource_limit_error_response(&error, kind, limits()).unwrap();
-        assert_eq!(encoded.status(), status);
-        assert_ne!(encoded.status(), StatusCode::TOO_MANY_REQUESTS);
-        assert_eq!(
-            decode_batch_response(&request(), &encoded, limits()).unwrap(),
-            DecodedResponse::ProtocolFailure {
-                error: error.clone(),
-                status_mismatch: None,
-            }
-        );
-    }
-}
-
-#[test]
-fn batch_success_body_requires_exactly_http_200() {
-    let request = request();
-    let response = BatchResponse {
-        responses: vec![
-            BatchResponseItem {
-                id: "object".into(),
-                outcome: Ok(BatchSuccess::Observe(observed_item(None))),
-            },
-            BatchResponseItem {
-                id: "interface".into(),
-                outcome: Err(ProtocolError {
-                    code: ProtocolErrorCode::InterfaceNotFound,
-                    message: "gone".into(),
-                }),
-            },
-        ],
-    };
-    let encoded = encode_batch_response(&request, &response, limits()).unwrap();
-    for status in [StatusCode::CREATED, StatusCode::ACCEPTED] {
-        let mut noncanonical = encoded.clone();
-        *noncanonical.status_mut() = status;
-        assert!(matches!(
-            decode_batch_response(&request, &noncanonical, limits()).unwrap_err(),
-            ClientResponseError::InvalidResponse { .. }
-        ));
-    }
-}
-
-#[test]
-fn top_level_batch_errors_use_the_batch_allowed_code_set() {
-    let invalid = ProtocolError {
-        code: ProtocolErrorCode::InvalidRequest,
-        message: "bad envelope".into(),
-    };
-    let encoded = encode_batch_error_response(&invalid, limits()).unwrap();
-    assert_eq!(
-        decode_batch_response(&request(), &encoded, limits()).unwrap(),
-        DecodedResponse::ProtocolFailure {
-            error: invalid,
-            status_mismatch: None,
-        }
-    );
-
-    let not_found = wip_http::http::Response::builder()
-        .status(StatusCode::NOT_FOUND)
-        .header("content-type", "application/json; charset=utf-8")
-        .body(br#"{"error":{"code":"not_found","message":"not a batch failure"}}"#.to_vec())
-        .unwrap();
-    assert!(matches!(
-        decode_batch_response(&request(), &not_found, limits()).unwrap_err(),
-        ClientResponseError::InvalidResponse {
-            kind: InvalidResponseKind::InvalidBatch,
-            ..
-        }
-    ));
-}
-
-#[test]
-fn unsupported_batch_descriptor_waits_for_envelope_correlation() {
-    let duplicate = wip_http::http::Response::builder()
-        .status(StatusCode::OK)
-        .header("content-type", "application/json; charset=utf-8")
-        .body(
-            br#"{"responses":[{"id":"interface","result":{"interface":"interface-v1","descriptor":{"format":"wip-interface/2","future":true}}},{"id":"interface","result":{"interface":"interface-v1","descriptor":{"format":"wip-interface/2"}}}]}"#
-                .to_vec(),
-        )
-        .unwrap();
-    assert!(matches!(
-        decode_batch_response(&request(), &duplicate, limits()).unwrap_err(),
-        ClientResponseError::InvalidResponse {
-            kind: InvalidResponseKind::InvalidBatch,
-            ..
-        }
-    ));
-
-    let missing = wip_http::http::Response::builder()
-        .status(StatusCode::OK)
-        .header("content-type", "application/json; charset=utf-8")
-        .body(
-            br#"{"responses":[{"id":"interface","result":{"interface":"interface-v1","descriptor":{"format":"wip-interface/2"}}}]}"#
-                .to_vec(),
-        )
-        .unwrap();
-    assert!(matches!(
-        decode_batch_response(&request(), &missing, limits()).unwrap_err(),
-        ClientResponseError::InvalidResponse {
-            kind: InvalidResponseKind::InvalidBatch,
-            ..
-        }
-    ));
-
-    let request = BatchRequest {
-        requests: vec![BatchRequestItem {
-            id: "interface".into(),
-            request: BatchRequestKind::FetchInterface(FetchInterfaceRequest {
-                interface: "interface-v1".into(),
-            }),
-        }],
-    };
-    assert!(matches!(
-        decode_batch_response(&request, &missing, limits()).unwrap_err(),
-        ClientResponseError::UnsupportedDescriptorFormat { format }
-            if format == "wip-interface/2"
-    ));
-}
-
-#[test]
-fn batch_response_must_have_exactly_the_requested_ids() {
-    let request = request();
-    let missing = BatchResponse {
-        responses: vec![BatchResponseItem {
-            id: "object".into(),
-            outcome: Ok(BatchSuccess::Observe(observed_item(None))),
-        }],
-    };
-    assert!(encode_batch_response(&request, &missing, limits()).is_err());
-}

crates/wip-http/tests/codecs.rs

@@ -10,15 +10,15 @@ use wip_http::wip_protocol::{
 };
 use wip_http::{
     ClientResponseError, CodecError, DecodedResponse, Endpoint, InvalidResponseKind, Limits,
-    ResourceLimitKind, decode_call_operation_metadata, decode_call_operation_request,
-    decode_call_operation_response, decode_fetch_interface_request,
-    decode_fetch_interface_response, decode_observe_request, decode_observe_response,
-    encode_call_operation_request, encode_call_operation_response, encode_fetch_interface_request,
-    encode_fetch_interface_response, encode_observe_request, encode_observe_response,
+    decode_call_operation_metadata, decode_call_operation_request, decode_call_operation_response,
+    decode_fetch_interface_request, decode_fetch_interface_response, decode_observe_request,
+    decode_observe_response, encode_call_operation_request, encode_call_operation_response,
+    encode_fetch_interface_request, encode_fetch_interface_response, encode_observe_request,
+    encode_observe_response,
 };
 
 fn limits() -> Limits {
-    Limits::new(1_000_000, 1_000_000, 100, 100).unwrap()
+    Limits::new(1_000_000, 1_000_000, 100).unwrap()
 }
 
 fn endpoint() -> Endpoint {
@@ -404,25 +404,17 @@ fn malformed_unknown_null_and_noncanonical_base64_are_rejected() {
 }
 
 #[test]
-fn caller_limits_bound_bytes_and_nesting() {
-    let tiny = Limits::new(8, 8, 2, 1).unwrap();
+fn caller_limits_remain_local_codec_failures() {
+    let tiny = Limits::new(8, 8, 2).unwrap();
     let too_large = decode_observe_request(br#"{"path":"/long","depth":0}"#, tiny).unwrap_err();
     assert!(matches!(&too_large, CodecError::BodyTooLarge { .. }));
-    assert_eq!(
-        too_large.resource_limit_kind(),
-        Some(ResourceLimitKind::RepresentationBytes)
-    );
 
     let nested = br#"{"path":[[["/"]]],"depth":0}"#;
-    let nesting_limited = Limits::new(1024, 1024, 2, 1).unwrap();
+    let nesting_limited = Limits::new(1024, 1024, 2).unwrap();
     let too_deep = decode_observe_request(nested, nesting_limited).unwrap_err();
     assert!(matches!(&too_deep, CodecError::NestingTooDeep { .. }));
-    assert_eq!(
-        too_deep.resource_limit_kind(),
-        Some(ResourceLimitKind::Logical)
-    );
 
-    let outbound_limited = Limits::new(1_000_000, 1_000_000, 1, 10).unwrap();
+    let outbound_limited = Limits::new(1_000_000, 1_000_000, 1).unwrap();
     assert!(
         encode_call_operation_request(
             &endpoint(),

crates/wip-http/tests/responses.rs

@@ -3,14 +3,13 @@ use wip_http::wip_protocol::{
     ObserveRequest, ProtocolError, ProtocolErrorCode, ProtocolInteraction,
 };
 use wip_http::{
-    ClientResponseError, DecodedResponse, InvalidResponseKind, Limits, ResourceLimitKind,
-    TransportFailureKind, decode_observe_response, encode_protocol_error_response,
-    encode_resource_limit_error_response, error_code_name, is_json_content_type, status_for_error,
-    status_for_resource_limit,
+    ClientResponseError, DecodedResponse, InvalidResponseKind, Limits, TransportFailureKind,
+    decode_observe_response, encode_protocol_error_response, error_code_name, is_json_content_type,
+    status_for_error,
 };
 
 fn limits() -> Limits {
-    Limits::new(64 * 1024, 64 * 1024, 32, 16).unwrap()
+    Limits::new(64 * 1024, 64 * 1024, 32).unwrap()
 }
 
 fn request() -> ObserveRequest {
@@ -120,41 +119,45 @@ fn every_protocol_code_has_stable_name_and_status() {
 }
 
 #[test]
-fn resource_limit_statuses_encode_and_decode_by_concrete_limit_class() {
+fn logical_resource_limit_uses_only_422_and_bare_413_is_transport_failure() {
     let error = ProtocolError {
         code: ProtocolErrorCode::ResourceLimitExceeded,
-        message: "bounded".into(),
+        message: "logical observation limit exceeded".into(),
     };
-    let cases = [
-        (
-            ResourceLimitKind::RepresentationBytes,
-            StatusCode::PAYLOAD_TOO_LARGE,
-        ),
-        (ResourceLimitKind::Logical, StatusCode::UNPROCESSABLE_ENTITY),
-    ];
-    for (kind, status) in cases {
-        assert_eq!(status_for_resource_limit(kind), status);
-        let encoded = encode_resource_limit_error_response(
-            ProtocolInteraction::Observe,
-            &error,
-            kind,
-            limits(),
-        )
-        .unwrap();
-        assert_eq!(encoded.status(), status);
-        assert_eq!(
-            decode_observe_response(&request(), &encoded, limits()).unwrap(),
-            DecodedResponse::ProtocolFailure {
-                error: error.clone(),
-                status_mismatch: None,
-            }
-        );
-    }
-
-    let default =
+    let encoded =
         encode_protocol_error_response(ProtocolInteraction::Observe, &error, limits()).unwrap();
-    assert_eq!(default.status(), StatusCode::UNPROCESSABLE_ENTITY);
-    assert_ne!(default.status(), StatusCode::TOO_MANY_REQUESTS);
+    assert_eq!(encoded.status(), StatusCode::UNPROCESSABLE_ENTITY);
+    assert_eq!(
+        decode_observe_response(&request(), &encoded, limits()).unwrap(),
+        DecodedResponse::ProtocolFailure {
+            error: error.clone(),
+            status_mismatch: None,
+        }
+    );
+
+    let mut noncanonical = encoded;
+    *noncanonical.status_mut() = StatusCode::PAYLOAD_TOO_LARGE;
+    assert_eq!(
+        decode_observe_response(&request(), &noncanonical, limits()).unwrap(),
+        DecodedResponse::ProtocolFailure {
+            error,
+            status_mismatch: Some(wip_http::StatusMismatch {
+                actual: StatusCode::PAYLOAD_TOO_LARGE,
+                expected: StatusCode::UNPROCESSABLE_ENTITY,
+            }),
+        }
+    );
+
+    let bare_413 = Response::builder()
+        .status(StatusCode::PAYLOAD_TOO_LARGE)
+        .body(Vec::<u8>::new())
+        .unwrap();
+    assert!(matches!(
+        decode_observe_response(&request(), &bare_413, limits()).unwrap_err(),
+        ClientResponseError::TransportBinding(failure)
+            if failure.status == StatusCode::PAYLOAD_TOO_LARGE
+                && failure.kind == TransportFailureKind::HttpStatus
+    ));
 }
 
 #[test]
@@ -171,6 +174,49 @@ fn rate_limit_status_without_protocol_envelope_stays_transport_failure() {
     ));
 }
 
+#[test]
+fn unsupported_response_content_coding_is_transport_failure() {
+    let mut encoded = encode_protocol_error_response(
+        ProtocolInteraction::Observe,
+        &ProtocolError {
+            code: ProtocolErrorCode::NotFound,
+            message: "missing".into(),
+        },
+        limits(),
+    )
+    .unwrap();
+    encoded
+        .headers_mut()
+        .insert("content-encoding", "gzip".parse().unwrap());
+    assert!(matches!(
+        decode_observe_response(&request(), &encoded, limits()).unwrap_err(),
+        ClientResponseError::TransportBinding(failure)
+            if failure.status == StatusCode::NOT_FOUND
+                && failure.kind == TransportFailureKind::UnsupportedContentCoding
+    ));
+
+    let success = response(StatusCode::OK, br#"{"object":{"name":"","interfaces":[]}}"#);
+    let mut identity = success.clone();
+    identity
+        .headers_mut()
+        .insert("content-encoding", "identity".parse().unwrap());
+    assert!(matches!(
+        decode_observe_response(&request(), &identity, limits()).unwrap(),
+        DecodedResponse::Success(_)
+    ));
+
+    let mut unsupported = success;
+    unsupported
+        .headers_mut()
+        .insert("content-encoding", "br".parse().unwrap());
+    assert!(matches!(
+        decode_observe_response(&request(), &unsupported, limits()).unwrap_err(),
+        ClientResponseError::TransportBinding(failure)
+            if failure.status == StatusCode::OK
+                && failure.kind == TransportFailureKind::UnsupportedContentCoding
+    ));
+}
+
 #[test]
 fn valid_success_body_requires_exactly_http_200() {
     let success_body = br#"{"object":{"name":"","interfaces":[]}}"#;

crates/wip-http/tests/routes.rs

@@ -14,7 +14,6 @@ fn endpoint_preserves_http_and_https_when_resolving_canonical_routes() {
             (Route::Observe, "v1/observe"),
             (Route::FetchInterface, "v1/fetch_interface"),
             (Route::CallOperation, "v1/call_operation"),
-            (Route::Batch, "v1/batch"),
         ];
         for (route, suffix) in expected {
             let url = format!("{scheme}://example.test/root/prefix/{suffix}");
@@ -61,7 +60,10 @@ fn inbound_http_metadata_enforces_post_route_and_json() {
         .header("content-type", "application/json")
         .body(Vec::<u8>::new())
         .unwrap();
-    assert!(validate_http_request(&endpoint, Route::Observe, &wrong_method).is_err());
+    let error = validate_http_request(&endpoint, Route::Observe, &wrong_method).unwrap_err();
+    assert!(matches!(&error, RequestMetadataError::MethodNotAllowed));
+    assert_eq!(error.status(), StatusCode::METHOD_NOT_ALLOWED);
+    assert_eq!(error.allow(), Some("POST"));
 
     let wrong_route = Request::builder()
         .method(Method::POST)
@@ -69,7 +71,21 @@ fn inbound_http_metadata_enforces_post_route_and_json() {
         .header("content-type", "application/json")
         .body(Vec::<u8>::new())
         .unwrap();
-    assert!(validate_http_request(&endpoint, Route::Observe, &wrong_route).is_err());
+    let error = validate_http_request(&endpoint, Route::Observe, &wrong_route).unwrap_err();
+    assert!(matches!(&error, RequestMetadataError::NotFound));
+    assert_eq!(error.status(), StatusCode::NOT_FOUND);
+    assert_eq!(error.allow(), None);
+
+    let query_and_wrong_method = Request::builder()
+        .method(Method::GET)
+        .uri("/wip/v1/observe?unexpected=true")
+        .header("content-type", "application/json")
+        .body(Vec::<u8>::new())
+        .unwrap();
+    assert!(matches!(
+        validate_http_request(&endpoint, Route::Observe, &query_and_wrong_method).unwrap_err(),
+        RequestMetadataError::NotFound
+    ));
 
     for accept in [
         "text/plain, */*;q=1, application/json;q=0",
@@ -114,6 +130,29 @@ fn inbound_http_metadata_enforces_post_route_and_json() {
         validate_http_request(&endpoint, Route::Observe, &unsupported_media_type).unwrap_err();
     assert!(matches!(&error, RequestMetadataError::UnsupportedMediaType));
     assert_eq!(error.status(), StatusCode::UNSUPPORTED_MEDIA_TYPE);
+
+    for coding in ["gzip", "identity, gzip"] {
+        let unsupported_coding = Request::builder()
+            .method(Method::POST)
+            .uri("/wip/v1/observe")
+            .header("content-type", "application/json")
+            .header("content-encoding", coding)
+            .body(Vec::<u8>::new())
+            .unwrap();
+        let error =
+            validate_http_request(&endpoint, Route::Observe, &unsupported_coding).unwrap_err();
+        assert!(matches!(&error, RequestMetadataError::UnsupportedMediaType));
+        assert_eq!(error.status(), StatusCode::UNSUPPORTED_MEDIA_TYPE);
+    }
+
+    let identity_coding = Request::builder()
+        .method(Method::POST)
+        .uri("/wip/v1/observe")
+        .header("content-type", "application/json")
+        .header("content-encoding", "identity")
+        .body(Vec::<u8>::new())
+        .unwrap();
+    assert!(validate_http_request(&endpoint, Route::Observe, &identity_coding).is_ok());
 }
 
 #[test]
@@ -130,6 +169,7 @@ fn invalid_endpoint_components_and_non_routes_are_rejected() {
     let endpoint = Endpoint::parse("http://example.test/wip").unwrap();
     for outside in [
         "http://example.test/wip/v1/unknown",
+        "http://example.test/wip/v1/batch",
         "http://example.test/wip/v1/observe/extra",
         "https://example.test/wip/v1/observe",
         "http://other.test/wip/v1/observe",

crates/wip-tui/src/app.rs

@@ -939,7 +939,7 @@ mod tests {
         // A request identity has no public constructor; derive one through the runtime.
         let mut client = wip_client::Client::new(
             wip_client::ClientLimits::new(1, 4, 4, 4, 4).unwrap(),
-            wip_http::Limits::new(1024, 1024, 8, 8).unwrap(),
+            wip_http::Limits::new(1024, 1024, 8).unwrap(),
         );
         let session = client
             .open_session(

crates/wip-tui/src/runtime.rs

@@ -862,8 +862,7 @@ fn collect_entries_at(
 /// Standard bounded wire policy used by the executable and integration tests.
 #[must_use]
 pub fn default_wire_limits() -> Limits {
-    Limits::new(256 * 1024, 2 * 1024 * 1024, 64, 64)
-        .expect("static runtime wire limits are nonzero")
+    Limits::new(256 * 1024, 2 * 1024 * 1024, 64).expect("static runtime wire limits are nonzero")
 }
 
 /// Runs the interactive executable using process configuration.