feat(web): add Subject creation to Memory index

web/workspace/src/lib/generated/memory-api.ts

@@ -35,6 +35,8 @@ export type MemoryStagingListResponse = { limit: number, returned_count: number,
 
 export type SubjektivSubjectState = "active" | "retired";
 
+export type SubjektivSubjectCreateRequest = { role: string, };
+
 export type SubjektivSubjectResponse = { id: string, role: string, state: SubjektivSubjectState, store_revision: number, created_at: string, updated_at: string, current_worker?: | import("./worker-launch-api").WorkerLaunchWorkerSummary | null, };
 
 export type SubjektivSubjectListResponse = { limit: number, items: Array<SubjektivSubjectResponse>, next_cursor?: string | null, has_more: boolean, };

web/workspace/src/lib/workspace/memory/api.ts

@@ -1,4 +1,5 @@
 import { MEMORY_API_LIMITS } from "#lib/generated/memory-api.ts";
+import { readBoundedJson, workspaceApiPath } from "#lib/workspace/api/http.ts";
 import type {
   Diagnostic,
   DiagnosticSeverity,
@@ -25,6 +26,7 @@ import type {
   SubjektivResidentSurfaceAvailability,
   SubjektivResidentSurfaceResponse,
   SubjektivResidentSurfaceSnapshot,
+  SubjektivSubjectCreateRequest,
   SubjektivSubjectListResponse,
   SubjektivSubjectResponse,
   SubjektivSubjectState,
@@ -81,6 +83,128 @@ export const MEMORY_API_LOAD_POLICY = {
   maxResponseBytes: MEMORY_API_LIMITS.maxResponseBytes,
 } as const;
 
+const MAX_SUBJECT_ROLE_BYTES = 256;
+const MAX_SUBJECT_CREATE_ERROR_BYTES = 1024 * 1024;
+
+export type SubjektivSubjectCreateErrorKind =
+  | "validation"
+  | "rejected"
+  | "unknown_outcome";
+
+export class SubjektivSubjectCreateError extends Error {
+  readonly kind: SubjektivSubjectCreateErrorKind;
+  readonly status: number | null;
+
+  constructor(
+    kind: SubjektivSubjectCreateErrorKind,
+    message: string,
+    status: number | null = null,
+  ) {
+    super(message);
+    this.name = "SubjektivSubjectCreateError";
+    this.kind = kind;
+    this.status = status;
+  }
+}
+
+export function validateSubjektivSubjectCreateRequest(
+  request: SubjektivSubjectCreateRequest,
+): SubjektivSubjectCreateRequest {
+  if (request.role.trim().length === 0) {
+    throw new SubjektivSubjectCreateError(
+      "validation",
+      "Subject role must not be empty.",
+    );
+  }
+  if (
+    new TextEncoder().encode(request.role).byteLength >
+      MAX_SUBJECT_ROLE_BYTES ||
+    /\p{Cc}/u.test(request.role)
+  ) {
+    throw new SubjektivSubjectCreateError(
+      "validation",
+      "Subject role must be at most 256 bytes and contain no control characters.",
+    );
+  }
+  return { role: request.role };
+}
+
+export async function createSubjektivSubject(
+  fetchFn: typeof fetch,
+  workspaceId: string,
+  request: SubjektivSubjectCreateRequest,
+): Promise<SubjektivSubjectResponse> {
+  const validated = validateSubjektivSubjectCreateRequest(request);
+  const path = workspaceApiPath(workspaceId, "/subjektiv/subjects");
+  let response: Response;
+  try {
+    response = await fetchFn(path, {
+      method: "POST",
+      headers: { "content-type": "application/json" },
+      body: JSON.stringify(validated),
+    });
+  } catch {
+    throw new SubjektivSubjectCreateError(
+      "unknown_outcome",
+      "The request outcome is unknown. A Subject may have been created.",
+    );
+  }
+
+  if (!response.ok) {
+    const message = await subjektivSubjectCreateErrorMessage(response);
+    if (response.status >= 400 && response.status < 500) {
+      throw new SubjektivSubjectCreateError(
+        "rejected",
+        message,
+        response.status,
+      );
+    }
+    throw new SubjektivSubjectCreateError(
+      "unknown_outcome",
+      "The request outcome is unknown. A Subject may have been created.",
+      response.status,
+    );
+  }
+
+  try {
+    const subject = parseSubjektivSubjectResponse(
+      await readBoundedJson(response, MEMORY_API_LIMITS.maxResponseBytes),
+    );
+    if (subject.role !== validated.role) {
+      throw new Error("created Subject role does not match the request");
+    }
+    return subject;
+  } catch {
+    throw new SubjektivSubjectCreateError(
+      "unknown_outcome",
+      "The Subject may have been created, but the response could not be confirmed.",
+    );
+  }
+}
+
+async function subjektivSubjectCreateErrorMessage(
+  response: Response,
+): Promise<string> {
+  try {
+    const payload = await readBoundedJson(
+      response,
+      MAX_SUBJECT_CREATE_ERROR_BYTES,
+    );
+    if (typeof payload === "object" && payload !== null) {
+      const record = payload as Record<string, unknown>;
+      if (typeof record.message === "string" && record.message.length > 0) {
+        return record.message;
+      }
+      if (typeof record.error === "string" && record.error.length > 0) {
+        return record.error;
+      }
+    }
+  } catch {
+    // A rejected request still has a known outcome even when its body is invalid.
+  }
+  return `Subject creation failed with HTTP ${response.status}.`;
+}
+
 export function parseMemoryDocumentResponse(
   value: unknown,
 ): MemoryDocumentResponse {

web/workspace/src/routes/w/[workspaceId]/memory/+page.svelte

@@ -1,10 +1,26 @@
 <script lang="ts">
+  import { goto } from '$app/navigation';
+  import { tick } from 'svelte';
   import { formatDate, workspaceRoute } from '#lib/workspace/api/http.ts';
+  import {
+    createSubjektivSubject,
+    SubjektivSubjectCreateError,
+  } from '#lib/workspace/memory/api.ts';
+  import type { SubjektivSubjectResponse } from '#lib/generated/memory-api.ts';
   import type { PageProps } from './$types';
 
   let { data }: PageProps = $props();
 
   const subjects = $derived(data.subjects.data?.items ?? []);
+  let createExpanded = $state(false);
+  let role = $state('');
+  let submitting = $state(false);
+  let createError = $state<string | null>(null);
+  let roleInvalid = $state(false);
+  let createOutcomeUnknown = $state(false);
+  let createdSubject = $state<SubjektivSubjectResponse | null>(null);
+  let createButton = $state<HTMLButtonElement>();
+  let roleInput = $state<HTMLInputElement>();
 
   function subjectHref(subjectId: string): string {
     return workspaceRoute(data.workspaceId, `/memory/${encodeURIComponent(subjectId)}`);
@@ -14,6 +30,69 @@
     const path = workspaceRoute(data.workspaceId, '/memory');
     return cursor ? `${path}?cursor=${encodeURIComponent(cursor)}` : path;
   }
+
+  async function openCreateForm(): Promise<void> {
+    createExpanded = true;
+    createError = null;
+    roleInvalid = false;
+    createOutcomeUnknown = false;
+    createdSubject = null;
+    await tick();
+    roleInput?.focus();
+  }
+
+  async function cancelCreate(): Promise<void> {
+    if (submitting) return;
+    createExpanded = false;
+    role = '';
+    createError = null;
+    roleInvalid = false;
+    createOutcomeUnknown = false;
+    createdSubject = null;
+    await tick();
+    createButton?.focus();
+  }
+
+  async function submitCreate(): Promise<void> {
+    if (submitting || createdSubject) return;
+    submitting = true;
+    createError = null;
+    roleInvalid = false;
+    createOutcomeUnknown = false;
+    try {
+      const subject = await createSubjektivSubject(fetch, data.workspaceId, { role });
+      createdSubject = subject;
+      try {
+        await goto(subjectHref(subject.id));
+      } catch {
+        createError = 'Subject created, but navigation failed. Open the created Subject below.';
+      }
+    } catch (error) {
+      if (error instanceof SubjektivSubjectCreateError) {
+        roleInvalid = error.kind === 'validation';
+        createOutcomeUnknown = error.kind === 'unknown_outcome';
+        createError = error.status === 401 || error.status === 403
+          ? 'You do not have permission to create Subjects in this Workspace.'
+          : error.message;
+        if (roleInvalid) {
+          await tick();
+          roleInput?.focus();
+        }
+      } else {
+        createOutcomeUnknown = true;
+        createError = 'The request outcome is unknown. A Subject may have been created.';
+      }
+    } finally {
+      submitting = false;
+    }
+  }
+
+  function createFormKeydown(event: KeyboardEvent): void {
+    if (event.key === 'Escape' && !submitting) {
+      event.preventDefault();
+      void cancelCreate();
+    }
+  }
 </script>
 
 <svelte:head>
@@ -26,13 +105,73 @@
     <div>
       <p class="memory-eyebrow">Memory</p>
       <h1 id="memory-subjects-heading">Subjects</h1>
-      <p>Read-only durable context, organized by explicit subject.</p>
+      <p>Durable context, organized by explicit subject.</p>
+    </div>
+    <div class="memory-header-actions">
+      {#if data.subjects.data}
+        <span class="memory-count">{subjects.length}{data.subjects.data.has_more ? '+' : ''} subject{subjects.length === 1 ? '' : 's'}</span>
+      {/if}
+      <button
+        bind:this={createButton}
+        type="button"
+        class="subject-create-trigger"
+        aria-expanded={createExpanded}
+        aria-controls="subject-create-panel"
+        onclick={() => void openCreateForm()}
+      >New Subject</button>
     </div>
-    {#if data.subjects.data}
-      <span class="memory-count">{subjects.length}{data.subjects.data.has_more ? '+' : ''} subject{subjects.length === 1 ? '' : 's'}</span>
-    {/if}
   </header>
 
+  {#if createExpanded}
+    <form
+      id="subject-create-panel"
+      class="subject-create-panel"
+      aria-labelledby="subject-create-heading"
+      aria-busy={submitting}
+      onsubmit={(event) => { event.preventDefault(); void submitCreate(); }}
+    >
+      <div class="subject-create-copy">
+        <h2 id="subject-create-heading">Create Subject</h2>
+        <p id="subject-role-help">Role describes the Subject’s durable identity. The service assigns its ID; creating it does not start or attach a Worker.</p>
+      </div>
+      <label class="subject-role-field">
+        <span>Role</span>
+        <input
+          bind:this={roleInput}
+          bind:value={role}
+          type="text"
+          autocomplete="off"
+          required
+          disabled={submitting || createdSubject !== null}
+          onkeydown={createFormKeydown}
+          aria-invalid={roleInvalid ? 'true' : undefined}
+          aria-describedby={createError ? 'subject-role-help subject-create-error' : 'subject-role-help'}
+        />
+      </label>
+      {#if createError}
+        <div
+          id="subject-create-error"
+          class:unknown-outcome={createOutcomeUnknown}
+          class="subject-create-error"
+          role="alert"
+        >
+          <p>{createError}</p>
+          {#if createOutcomeUnknown}
+            <p><a href={pageHref()}>Check the first Subjects page before retrying.</a></p>
+          {:else if createdSubject}
+            <p><a href={subjectHref(createdSubject.id)}>Open {createdSubject.id}</a></p>
+          {/if}
+        </div>
+      {/if}
+      <div class="subject-create-actions">
+        <button type="submit" disabled={submitting || createdSubject !== null}>
+          {submitting ? 'Creating…' : 'Create Subject'}
+        </button>
+        <button type="button" class="subject-create-cancel" disabled={submitting} onclick={() => void cancelCreate()}>Cancel</button>
+      </div>
+    </form>
+  {/if}
+
   {#if data.subjects.data}
     {#if subjects.length === 0}
       <div class="memory-state" role="status" data-memory-state="empty">
@@ -127,6 +266,111 @@
     font-size: var(--font-size-compact);
   }
 
+  .memory-header-actions,
+  .subject-create-actions {
+    display: flex;
+    align-items: center;
+    flex-wrap: wrap;
+    gap: var(--space-3);
+  }
+
+  .memory-header-actions {
+    justify-content: flex-end;
+  }
+
+  .subject-create-trigger,
+  .subject-create-actions button {
+    min-height: 2.25rem;
+    border: 0;
+    border-radius: var(--radius-soft);
+    padding: var(--space-2) var(--space-4);
+    background: var(--accent);
+    color: var(--bg);
+    font-weight: 700;
+    cursor: pointer;
+  }
+
+  .subject-create-trigger:hover,
+  .subject-create-trigger:focus-visible,
+  .subject-create-actions button:hover:not(:disabled),
+  .subject-create-actions button:focus-visible:not(:disabled) {
+    filter: brightness(1.08);
+  }
+
+  .subject-create-actions button:disabled {
+    cursor: not-allowed;
+    opacity: 0.55;
+  }
+
+  .subject-create-actions .subject-create-cancel {
+    border: 1px solid var(--line);
+    background: transparent;
+    color: var(--text-strong);
+  }
+
+  .subject-create-actions {
+    grid-column: 3;
+    grid-row: 1;
+  }
+
+  .subject-create-panel {
+    display: grid;
+    grid-template-columns: minmax(14rem, 0.8fr) minmax(18rem, 1fr) auto;
+    align-items: end;
+    gap: var(--space-4);
+    padding: var(--space-4);
+    background: var(--bg-raised);
+    border-radius: var(--radius-soft);
+  }
+
+  .subject-create-copy h2,
+  .subject-create-copy p,
+  .subject-create-error p {
+    margin: 0;
+  }
+
+  .subject-create-copy p,
+  .subject-create-error {
+    margin-top: var(--space-1);
+    color: var(--text-muted);
+    font-size: var(--font-size-compact);
+  }
+
+  .subject-role-field {
+    display: grid;
+    gap: var(--space-1);
+    color: var(--text-muted);
+    font-size: var(--font-size-compact);
+    font-weight: 700;
+  }
+
+  .subject-role-field input {
+    width: 100%;
+    min-width: 0;
+    border: 1px solid var(--line);
+    border-radius: var(--radius-soft);
+    padding: var(--space-2) var(--space-3);
+    background: var(--bg);
+    color: var(--text-strong);
+  }
+
+  .subject-role-field input[aria-invalid='true'] {
+    border-color: var(--danger);
+  }
+
+  .subject-create-error {
+    grid-column: 2 / -1;
+    color: var(--danger);
+  }
+
+  .subject-create-error a {
+    color: inherit;
+  }
+
+  .subject-create-error.unknown-outcome {
+    color: var(--warning);
+  }
+
   .subject-list {
     display: grid;
     border-top: 1px solid var(--line);
@@ -231,6 +475,17 @@
   }
 
   @media (max-width: 900px) {
+    .subject-create-panel {
+      grid-template-columns: minmax(0, 1fr);
+      align-items: stretch;
+    }
+
+    .subject-create-error,
+    .subject-create-actions {
+      grid-column: 1;
+      grid-row: auto;
+    }
+
     .subject-row {
       grid-template-columns: minmax(0, 1fr);
       gap: var(--space-3);
@@ -243,6 +498,14 @@
       gap: var(--space-2);
     }
 
+    .memory-header-actions {
+      justify-content: flex-start;
+    }
+
+    .subject-create-panel {
+      padding: var(--space-3);
+    }
+
     .subject-row {
       padding-inline: 0;
     }

web/workspace/src/routes/w/[workspaceId]/memory/memory-page.browser.spec.ts

@@ -1,12 +1,29 @@
 // @vitest-environment happy-dom
 
-import { cleanup, render, screen, waitFor } from "@testing-library/svelte";
-import { afterEach, expect, test } from "vitest";
+import {
+  cleanup,
+  fireEvent,
+  render,
+  screen,
+  waitFor,
+} from "@testing-library/svelte";
+import { afterEach, expect, test, vi } from "vitest";
+
+const { gotoMock } = vi.hoisted(() => ({
+  gotoMock: vi.fn(async () => {}),
+}));
+
+vi.mock("$app/navigation", () => ({ goto: gotoMock }));
+
 import SubjectIndexPage from "./+page.svelte";
 import SubjectPage from "./[subjectId]/+page.svelte";
 import MemoryDetailPage from "./[subjectId]/[memoryId]/+page.svelte";
 
-afterEach(cleanup);
+afterEach(() => {
+  cleanup();
+  vi.unstubAllGlobals();
+  vi.clearAllMocks();
+});
 
 const result = <T>(data: T | null, error: string | null = null) => ({
   data,
@@ -24,6 +41,18 @@ function subject() {
   };
 }
 
+function subjectIndexData(items = [subject()]) {
+  return {
+    workspaceId: "workspace-1",
+    cursor: null,
+    subjects: result({
+      limit: 100,
+      items,
+      has_more: false,
+    }),
+  };
+}
+
 test("renders the subject index as the Memory product entry", () => {
   render(SubjectIndexPage, {
     data: {
@@ -40,6 +69,7 @@ test("renders the subject index as the Memory product entry", () => {
 
   expect(screen.getByRole("heading", { name: "Subjects", level: 1 })).not
     .toBeNull();
+  expect(screen.getByRole("button", { name: "New Subject" })).not.toBeNull();
   expect(screen.getByRole("link", { name: /Release coordinator/ })).not
     .toBeNull();
   expect(screen.getByText("subject-1")).not.toBeNull();
@@ -50,6 +80,134 @@ test("renders the subject index as the Memory product entry", () => {
   expect(screen.queryByText("Staging")).toBeNull();
 });
 
+test("creates one Subject with the exact role and navigates to its generated detail", async () => {
+  let resolveRequest!: (response: Response) => void;
+  const response = new Promise<Response>((resolve) => {
+    resolveRequest = resolve;
+  });
+  const fetchMock = vi.fn(() => response);
+  vi.stubGlobal("fetch", fetchMock);
+  render(SubjectIndexPage, { data: subjectIndexData() } as never);
+
+  const trigger = screen.getByRole("button", { name: "New Subject" });
+  await fireEvent.click(trigger);
+  const roleInput = screen.getByRole("textbox", {
+    name: "Role",
+  }) as HTMLInputElement;
+  await waitFor(() => expect(document.activeElement).toBe(roleInput));
+  await fireEvent.input(roleInput, { target: { value: "  Review lead  " } });
+
+  const submit = screen.getByRole("button", { name: "Create Subject" });
+  await fireEvent.click(submit);
+  await waitFor(() => expect(fetchMock).toHaveBeenCalledTimes(1));
+  expect(
+    screen.getByRole("button", { name: "Creating…" }).hasAttribute("disabled"),
+  )
+    .toBe(true);
+  await fireEvent.click(screen.getByRole("button", { name: "Creating…" }));
+  expect(fetchMock).toHaveBeenCalledTimes(1);
+
+  resolveRequest(Response.json({
+    id: "generated-subject-1",
+    role: "  Review lead  ",
+    state: "active",
+    store_revision: 0,
+    created_at: "2026-01-03T00:00:00Z",
+    updated_at: "2026-01-03T00:00:00Z",
+  }, { status: 201 }));
+  await waitFor(() => {
+    expect(gotoMock).toHaveBeenCalledWith(
+      "/w/workspace-1/memory/generated-subject-1",
+    );
+  });
+
+  const [path, init] = fetchMock.mock.calls[0] as unknown as [
+    string,
+    RequestInit,
+  ];
+  expect(path).toBe("/api/w/workspace-1/subjektiv/subjects");
+  expect(init.method).toBe("POST");
+  expect(init.body).toBe('{"role":"  Review lead  "}');
+});
+
+test("keeps creation available for an empty list and restores focus on cancel", async () => {
+  vi.stubGlobal("fetch", vi.fn());
+  render(SubjectIndexPage, { data: subjectIndexData([]) } as never);
+
+  expect(screen.getByText("No Memory subjects.")).not.toBeNull();
+  const trigger = screen.getByRole("button", { name: "New Subject" });
+  await fireEvent.click(trigger);
+  const input = screen.getByRole("textbox", {
+    name: "Role",
+  }) as HTMLInputElement;
+  await fireEvent.input(input, { target: { value: "Draft role" } });
+  await fireEvent.keyDown(input, { key: "Escape" });
+  await waitFor(() => expect(document.activeElement).toBe(trigger));
+  expect(screen.queryByRole("textbox", { name: "Role" })).toBeNull();
+});
+
+test("preserves invalid and rejected role drafts with accessible errors", async () => {
+  const fetchMock = vi.fn(() =>
+    Promise.resolve(Response.json(
+      {
+        error: "Forbidden",
+        message: "workspace permission denied",
+        diagnostics: [],
+      },
+      { status: 403 },
+    ))
+  );
+  vi.stubGlobal("fetch", fetchMock);
+  render(SubjectIndexPage, { data: subjectIndexData() } as never);
+
+  await fireEvent.click(screen.getByRole("button", { name: "New Subject" }));
+  const input = screen.getByRole("textbox", {
+    name: "Role",
+  }) as HTMLInputElement;
+  await fireEvent.input(input, { target: { value: "   " } });
+  await fireEvent.click(screen.getByRole("button", { name: "Create Subject" }));
+  expect(screen.getByRole("alert").textContent).toContain("must not be empty");
+  expect(input.getAttribute("aria-invalid")).toBe("true");
+  expect(input.value).toBe("   ");
+  expect(fetchMock).not.toHaveBeenCalled();
+
+  await fireEvent.input(input, { target: { value: "Release reviewer" } });
+  await fireEvent.click(screen.getByRole("button", { name: "Create Subject" }));
+  await waitFor(() => {
+    expect(screen.getByRole("alert").textContent).toContain(
+      "do not have permission",
+    );
+  });
+  expect(input.value).toBe("Release reviewer");
+  expect(input.getAttribute("aria-invalid")).toBeNull();
+  expect(fetchMock).toHaveBeenCalledTimes(1);
+});
+
+test("warns about an unknown create outcome without replaying the POST", async () => {
+  const fetchMock = vi.fn(() =>
+    Promise.reject(new TypeError("connection reset"))
+  );
+  vi.stubGlobal("fetch", fetchMock);
+  render(SubjectIndexPage, { data: subjectIndexData() } as never);
+
+  await fireEvent.click(screen.getByRole("button", { name: "New Subject" }));
+  const input = screen.getByRole("textbox", {
+    name: "Role",
+  }) as HTMLInputElement;
+  await fireEvent.input(input, { target: { value: "Incident coordinator" } });
+  await fireEvent.click(screen.getByRole("button", { name: "Create Subject" }));
+  await waitFor(() => {
+    expect(screen.getByRole("alert").textContent).toContain(
+      "may have been created",
+    );
+  });
+  expect(screen.getByRole("link", { name: /Check the first Subjects page/ }))
+    .not.toBeNull();
+  expect(input.value).toBe("Incident coordinator");
+  expect(fetchMock).toHaveBeenCalledTimes(1);
+  expect(gotoMock).not.toHaveBeenCalled();
+});
+
 test("renders a ready resident surface and committed Memory lifecycle states", async () => {
   render(SubjectPage, {
     data: {
@@ -62,7 +220,8 @@ test("renders a ready resident surface and committed Memory lifecycle states", a
         availability: "ready" as const,
         snapshot: {
           snapshot_id: "snapshot-1",
-          body_md: "# Resident context\n\nUse the **current** committed record.",
+          body_md:
+            "# Resident context\n\nUse the **current** committed record.",
           memory_refs: [{ memory_id: "memory-1", revision: 3 }],
           built_from_store_revision: 9,
           created_at: "2026-01-02T03:04:05Z",

web/workspace/tests/memory-api.test.ts

@@ -3,6 +3,7 @@ declare const Deno: {
 };
 
 import {
+  createSubjektivSubject,
   parseMemoryStagingListResponse,
   parseSubjektivMemoryListRevisionsResponse,
   parseSubjektivMemoryQueryResponse,
@@ -10,6 +11,8 @@ import {
   parseSubjektivResidentSurfaceResponse,
   parseSubjektivSubjectListResponse,
   parseSubjektivSubjectResponse,
+  SubjektivSubjectCreateError,
+  validateSubjektivSubjectCreateRequest,
 } from "../src/lib/workspace/memory/api.ts";
 
 function stable(value: unknown): unknown {
@@ -44,6 +47,30 @@ function assertThrows(fn: () => void, expectedMessage: string): void {
   throw new Error(`expected function to throw ${expectedMessage}`);
 }
 
+async function assertSubjectCreateRejects(
+  fn: () => Promise<unknown>,
+  expectedKind: SubjektivSubjectCreateError["kind"],
+  expectedMessage: string,
+  expectedStatus: number | null = null,
+): Promise<void> {
+  try {
+    await fn();
+  } catch (error) {
+    if (!(error instanceof SubjektivSubjectCreateError)) throw error;
+    assertEquals(error.kind, expectedKind);
+    assertEquals(error.status, expectedStatus);
+    if (!error.message.includes(expectedMessage)) {
+      throw new Error(
+        `expected ${JSON.stringify(error.message)} to include ${
+          JSON.stringify(expectedMessage)
+        }`,
+      );
+    }
+    return;
+  }
+  throw new Error(`expected Subject creation to reject with ${expectedKind}`);
+}
+
 function subject(id = "subject-1") {
   return {
     id,
@@ -198,6 +225,117 @@ Deno.test("Subject list parser preserves the exact bounded response", () => {
   );
 });
 
+Deno.test("Subject create request mirrors Backend role validation without rewriting input", () => {
+  assertEquals(
+    validateSubjektivSubjectCreateRequest({ role: "  Release coordinator  " }),
+    { role: "  Release coordinator  " },
+  );
+  assertThrows(
+    () => validateSubjektivSubjectCreateRequest({ role: "   " }),
+    "must not be empty",
+  );
+  assertThrows(
+    () => validateSubjektivSubjectCreateRequest({ role: "line\nbreak" }),
+    "control characters",
+  );
+  assertThrows(
+    () => validateSubjektivSubjectCreateRequest({ role: "界".repeat(86) }),
+    "at most 256 bytes",
+  );
+});
+
+Deno.test("Subject create client sends the exact typed body once and parses the created Subject", async () => {
+  const requests: Array<{ path: string; init?: RequestInit }> = [];
+  const fetchFn = (async (path: string | URL | Request, init?: RequestInit) => {
+    requests.push({ path: String(path), init });
+    return Response.json({
+      ...subject("subject-created"),
+      role: "  Release coordinator  ",
+    }, { status: 201 });
+  }) as typeof fetch;
+
+  const created = await createSubjektivSubject(fetchFn, "workspace one", {
+    role: "  Release coordinator  ",
+  });
+  assertEquals(created, {
+    ...subject("subject-created"),
+    role: "  Release coordinator  ",
+  });
+  assertEquals(requests.length, 1);
+  assertEquals(requests[0].path, "/api/w/workspace%20one/subjektiv/subjects");
+  assertEquals(requests[0].init?.method, "POST");
+  assertEquals(requests[0].init?.body, '{"role":"  Release coordinator  "}');
+});
+
+Deno.test("Subject create client distinguishes rejected and unknown outcomes without retrying", async () => {
+  let rejectedCalls = 0;
+  const rejectedFetch = (async () => {
+    rejectedCalls += 1;
+    return Response.json(
+      {
+        error: "Forbidden",
+        message: "workspace permission denied",
+        diagnostics: [],
+      },
+      { status: 403 },
+    );
+  }) as typeof fetch;
+  await assertSubjectCreateRejects(
+    () =>
+      createSubjektivSubject(rejectedFetch, "workspace-1", {
+        role: "Reviewer",
+      }),
+    "rejected",
+    "workspace permission denied",
+    403,
+  );
+  assertEquals(rejectedCalls, 1);
+
+  let serverErrorCalls = 0;
+  const serverErrorFetch = (async () => {
+    serverErrorCalls += 1;
+    return Response.json({ error: "Internal Server Error" }, { status: 500 });
+  }) as typeof fetch;
+  await assertSubjectCreateRejects(
+    () =>
+      createSubjektivSubject(serverErrorFetch, "workspace-1", {
+        role: "Reviewer",
+      }),
+    "unknown_outcome",
+    "may have been created",
+    500,
+  );
+  assertEquals(serverErrorCalls, 1);
+
+  let mismatchCalls = 0;
+  const mismatchFetch = (async () => {
+    mismatchCalls += 1;
+    return Response.json(subject("subject-created"), { status: 201 });
+  }) as typeof fetch;
+  await assertSubjectCreateRejects(
+    () =>
+      createSubjektivSubject(mismatchFetch, "workspace-1", {
+        role: "Reviewer",
+      }),
+    "unknown_outcome",
+    "could not be confirmed",
+  );
+  assertEquals(mismatchCalls, 1);
+
+  let unknownCalls = 0;
+  const unknownFetch = (async () => {
+    unknownCalls += 1;
+    throw new TypeError("connection reset");
+  }) as typeof fetch;
+  await assertSubjectCreateRejects(
+    () =>
+      createSubjektivSubject(unknownFetch, "workspace-1", { role: "Reviewer" }),
+    "unknown_outcome",
+    "may have been created",
+  );
+  assertEquals(unknownCalls, 1);
+});
+
 Deno.test("Resident surface parser accepts ready-empty and enforces snapshot invariants", () => {
   const readyEmpty = {
     subject_id: "subject-1",