@@ -584,14 +584,11 @@ describe("Tier CIV — an identity belongs to one answer of one import", () => {
 });
 
 /**
- * Tier PA10b — two sibling spawns resolving at the same time.
+ * Tier PA10b — serial component-answer capture.
  *
- * `<All>` lets two `<Spawn>` children have an import open together, so a
- * resolution is no longer the only one in flight. What makes an answer this
- * import's is the exact window it was asked in, and windows now belong to the
- * engine scope that opened them — so these rows are written with two real
- * scopes standing for two spawns, and never with one spawn's bookkeeping
- * standing in for the other's.
+ * Each request retains the window that was open when its handler began. A
+ * descendant scope preserves that correlation, and closing the window makes
+ * the retained request unable to record an answer’s identity in a later one.
  */
 describe("Tier PA10b — one serial resolution window", () => {
   /**
 
@@ -279,30 +279,65 @@ describe("protected generated component answers", () => {
   it("refuses copied, mutated, wrapped, unclaimed, misidentified and wrong-form answers", function* () {
     const source = `<Evaluate text={'<Syntax />'} />`;
     const ran: string[] = [];
-    const transforms: ((answer: FunctionComponentDefinition) => FunctionComponentDefinition)[] = [
-      (answer) => ({ ...answer }),
-      (answer) => ({
-        ...answer,
-        *fn(): Operation<string> {
-          ran.push("same name");
-          return "forged";
+    const variants: {
+      name: string;
+      options: Parameters<typeof syntaxProfile>[0];
+      reason: string;
+    }[] = [
+      {
+        name: "copied",
+        options: { transform: (answer) => ({ ...answer }) },
+        reason: "carries no identity",
+      },
+      {
+        name: "replaced body",
+        options: {
+          transform: (answer) => ({
+            ...answer,
+            *fn(): Operation<string> {
+              ran.push("same name");
+              return "forged";
+            },
+          }),
         },
-      }),
-      independentWrapper,
-      (answer) => {
-        answer.props = { type: "object" };
-        return answer;
+        reason: "carries no identity",
+      },
+      {
+        name: "wrapped",
+        options: { transform: independentWrapper },
+        reason: "carries no identity",
+      },
+      {
+        name: "mutated",
+        options: {
+          transform: (answer) => {
+            answer.props = { type: "object" };
+            return answer;
+          },
+        },
+        reason: "carries no identity",
+      },
+      { name: "unclaimed", options: { unclaimed: true }, reason: "carries no identity" },
+      {
+        name: "misidentified",
+        options: { revision: "2" },
+        reason: "chain answered with test://syntax-provider#Syntax@2",
       },
     ];
-    for (const transform of transforms) {
-      const stream = new InMemoryStream();
-      expect(yield* refusal(run(source, [syntaxProfile({ transform })], stream))).toBeTruthy();
-      expect(admissions(yield* stream.readAll())).toHaveLength(0);
-    }
-    for (const options of [{ unclaimed: true }, { revision: "2" }]) {
+    for (const { name, options, reason } of variants) {
       const stream = new InMemoryStream();
-      expect(yield* refusal(run(source, [syntaxProfile(options)], stream))).toBeTruthy();
-      expect(admissions(yield* stream.readAll())).toHaveLength(0);
+      expect({
+        variant: name,
+        refusal: yield* refusal(run(source, [syntaxProfile(options)], stream)),
+      }).toEqual({
+        variant: name,
+        refusal: expect.stringContaining(reason),
+      });
+      expect({ variant: name, admissions: admissions(yield* stream.readAll()) }).toEqual({
+        variant: name,
+        admissions: [],
+      });
+      expect({ variant: name, ran }).toEqual({ variant: name, ran: [] });
     }
     expect(
       yield* refusal(run(`<Evaluate text={'<Syntax></Syntax>'} />`, [syntaxProfile()])),
 
@@ -4,6 +4,8 @@ import { createContext, ensure, scoped, spawn, suspend, withResolvers } from "ef
 import type { Operation } from "effection";
 import { InMemoryStream } from "@executablemd/durable-streams";
 import { Execution } from "../api.ts";
+import { parseFilesFatal } from "@executablemd/runtime";
+import { fatalCause } from "../src/errors.ts";
 import { collect, execute, Execution as RootExecution, inlineSource } from "../mod.ts";
 import { executeInstalled, fileReadEntry, Markdown, sourceDigest } from "../host.ts";
 import type { JournalAdmission } from "../host.ts";
@@ -240,7 +242,10 @@ describe("Tier EI — execution-owned initialization", () => {
   });
 
   it("EI7: a no-op initializer invents no Files provider; explicit initialization supplies one", function* () {
-    expect(String(yield* failure(run('<File path="note.md" />')))).toContain("Files");
+    expect(parseFilesFatal(fatalCause(yield* failure(run('<File path="note.md" />'))))).toEqual({
+      type: "executablemd.runtime.files-fatal/v1",
+      kind: "provider-unavailable",
+    });
     const files = recordedFiles({ "note.md": "INSTALLED BY INIT" });
     const output = yield* scoped(function* () {
       yield* Execution.around({
@@ -253,6 +258,9 @@ describe("Tier EI — execution-owned initialization", () => {
     });
     expect(output).toContain("INSTALLED BY INIT");
     expect(files.performed).toEqual(["read note.md"]);
-    expect(String(yield* failure(run('<File path="note.md" />')))).toContain("Files");
+    expect(parseFilesFatal(fatalCause(yield* failure(run('<File path="note.md" />'))))).toEqual({
+      type: "executablemd.runtime.files-fatal/v1",
+      kind: "provider-unavailable",
+    });
   });
 });
@@ -1,6 +1,6 @@
 import { describe, it } from "@executablemd/test-support/bdd";
 import { expect } from "@executablemd/test-support/expect";
-import { ensure, scoped, sleep, spawn, withResolvers } from "effection";
+import { ensure, scoped, spawn, withResolvers } from "effection";
 import type { Subscription } from "effection";
 import { createBlockCounter, expandSegments } from "../src/expand.ts";
 import { regionStream } from "../src/expansion-region.ts";
@@ -1469,6 +1469,7 @@ describe("Tier SR — expanding installed structural syntax", () => {
   it("SR7: one demand permits one chunk, and later work waits for later demand", function* () {
     const order: string[] = [];
     const released = withResolvers<void>();
+    const firstDelivered = withResolvers<void>();
     const environment = yield* installedEnvironment(
       [structuralDeclaration(), regionDeclaration()],
       function* (request) {
@@ -1483,6 +1484,7 @@ describe("Tier SR — expanding installed structural syntax", () => {
         // element's text asks again — each ask is one more permission to work.
         const first = yield* readText(subscription);
         order.push(`first:${first}`);
+        firstDelivered.resolve();
         yield* released.operation;
         const second = yield* readText(subscription);
         order.push(`second:${second}`);
@@ -1505,9 +1507,7 @@ describe("Tier SR — expanding installed structural syntax", () => {
       yield* spawn(function* () {
         // Released only once the first chunk has been delivered, so the second
         // segment's authored work cannot have run before this point.
-        while (!order.some((entry) => entry.startsWith("first:"))) {
-          yield* sleep(0);
-        }
+        yield* firstDelivered.operation;
         expect(order).not.toContain("ran:2");
         released.resolve();
       });
 
@@ -181,11 +181,16 @@ describe("Tier SA — contextual Syntax", () => {
       .snapshot()
       .filter((event) => event.type === "yield" && event.description.type === "syntax_symbols");
     expect(records).toHaveLength(2);
-    for (const record of records) {
+    for (const [index, record] of records.entries()) {
       if (record.type !== "yield" || record.result.status !== "ok") {
-        throw new Error("no retained Syntax answer");
+        throw new Error(
+          `Syntax occurrence ${index + 1} retained an unexpected result: ${JSON.stringify(record)}`,
+        );
       }
-      expect(JSON.stringify(record.result.value)).toContain("FINAL NAMED");
+      expect({ occurrence: index + 1, retained: JSON.stringify(record.result.value) }).toEqual({
+        occurrence: index + 1,
+        retained: expect.stringContaining("FINAL NAMED"),
+      });
     }
   });
 
 
@@ -22,6 +22,11 @@
  * fails under Deno, one missing from `package.json` fails under Node and Bun,
  * and only running all three tells those apart.
  *
+ * Emitted Git API identity composition across physical package copies is
+ * exercised by "publishes contextual Git APIs that compose across copies and
+ * loads a named Plugin" in `scripts/tests/cli-npm-bin.test.ts`; this file holds
+ * the portable source export-map contract.
+ *
  * Read through `Reflect.get` rather than a cast: what a module exported is
  * whatever it exported, and the members below are proven present rather than
  * assumed.
 
@@ -3,9 +3,9 @@
  *
  * `GitQuery.resolve()` verifies and resolves one revision expression in the
  * contextual working directory. The default invokes the Git CLI; a host or a
- * test replaces it lexically. Nothing here shells out: every test either
- * replaces `GitQuery` or stubs the process boundary beneath it, so the suite
- * runs the same wherever it is checked out.
+ * test replaces it lexically. GT1–GT5 replace `GitQuery` or stub the process
+ * boundary. GT6–GT7 exercise the shipped default against temporary directories,
+ * including a real Git checkout.
  */
 
 import { describe, it } from "@executablemd/test-support/bdd";
 
@@ -119,7 +119,13 @@ describe("<AssertThrows>", () => {
       ),
     );
     expect(run.results[0]?.status).toBe("fail");
-    expect(run.results[0]?.error?.message ?? "").not.toContain("none was raised");
+    expect(run.results[0]?.error).toMatchObject({
+      kind: "assertion",
+      actual: "1",
+      expected: "2",
+    });
+    expect(run.output).toContain("**AssertEquals** failed");
+    expect(run.output).not.toContain("**AssertThrows** failed");
   });
 
   it("stops expanding body children after the first raised error, rendering nothing", function* () {
 
@@ -43,6 +43,7 @@ import {
   type WorkflowWorkspaceMutation,
   type WorkflowWorkspaceTransaction,
 } from "../src/deno/workspace/effect.ts";
+import { journalableWorkspaceCode } from "../src/deno/workspace/errors.ts";
 import { readWorkflowWorkspace } from "../src/deno/workspace/inspect.ts";
 import type { WorkflowWorkspaceSnapshot } from "../src/deno/workspace/inspect.ts";
 import type {
@@ -199,18 +200,24 @@ function retainedRepositoryNames(path: string): string[] {
   }
 }
 
+function* workspaceContent(read: Operation<string>): Operation<string | undefined> {
+  try {
+    return yield* read;
+  } catch (error) {
+    if (journalableWorkspaceCode(error) === "ENOENT") {
+      return undefined;
+    }
+    throw error;
+  }
+}
+
 function* inspectWorkspace(
   database: WorkflowRunDatabase,
   path: string,
 ): Operation<{ root: string; content: string | undefined }> {
   const inspected = yield* database.transact(function* (transaction) {
     return yield* withPrivateWorkspaceTransaction(database, transaction, function* (workspace) {
-      let content: string | undefined;
-      try {
-        content = yield* workspace.filesystem.readTextFile(path);
-      } catch {
-        content = undefined;
-      }
+      const content = yield* workspaceContent(workspace.filesystem.readTextFile(path));
       return {
         root: yield* workspace.currentRoot(),
         content,
@@ -316,6 +323,19 @@ function setSqliteAuthorizer(
 }
 
 describe("Tier WAC — atomic provider-level Workspace effects", () => {
+  it("Workspace observation preserves a read failure that is not genuine absence", function* () {
+    const failures = [
+      Object.assign(new Error("Workspace read denied"), { code: "EACCES" }),
+      Object.assign(new Error("Workspace absence impostor"), { code: "ENOENT" }),
+    ];
+    for (const failure of failures) {
+      const read = (function* (): Operation<string> {
+        throw failure;
+      })();
+      expect(yield* raised(workspaceContent(read))).toBe(failure);
+    }
+  });
+
   it("WAC1: mutation, root, filtered Yield and commit become visible together", function* () {
     const root = yield* useStorageRoot();
     const runId = "atomic-success";
@@ -1653,7 +1673,7 @@ describe("Tier WAC — atomic provider-level Workspace effects", () => {
     });
   });
 
-  it("WAC24: a row written through the storage view commits with the effect's bytes", function* () {
+  it("WAC27: a row written through the storage view commits with the effect's bytes", function* () {
     const root = yield* useStorageRoot();
     const runId = "atomic-storage-commit";
 
@@ -1697,7 +1717,7 @@ describe("Tier WAC — atomic provider-level Workspace effects", () => {
     });
   });
 
-  it("WAC25: a refused mutation takes its rows back with its bytes", function* () {
+  it("WAC28: a refused mutation takes its rows back with its bytes", function* () {
     const root = yield* useStorageRoot();
     const runId = "atomic-storage-rollback";
 
@@ -1753,7 +1773,7 @@ describe("Tier WAC — atomic provider-level Workspace effects", () => {
    * its root is still open, which is exactly where "for this callback" has to
    * be a fact rather than a convention.
    */
-  it("WAC26: every capability a mutation retained answers nothing once it returned", function* () {
+  it("WAC29: every capability a mutation retained answers nothing once it returned", function* () {
     const root = yield* useStorageRoot();
     const runId = "atomic-storage-retained";
     const path = join(root, `${runId}.sqlite`);
 
@@ -11777,7 +11777,7 @@ visible warning blocks, gather into a separate error report).
 | FL27 | Colocated document | `xmd test packages/core/src/components/File.test.md` covers both forms, `as` capture, nested parents, replacement, exact content for both authoring shapes, a leading-dots name, and isolation between temporary directories — with no search path and no JavaScript |
 | FL34–FL35 | The authored form decides the effect | A self-closing `<File />` reads and never writes, and a paired `<File>` writes and never reads, under a contextual `hasContent` handler installed outside the invocation that lies consistently *and* under one that answers `[false, true]` / `[true, false]`. A sibling reporting the contextual answer proves the handler live; the provider calls and the file bytes prove the element followed how it was written (§5.6) |
 | FL36 | An honest chain | With no handler interfering, both forms reach the same providers and produce the same bytes |
-| FL37 | A look-alike is not an invocation | The definition called with an object implementing `hasContent()` — the whole public shape, reporting the answer that would select the write branch — refuses before reaching a provider, leaving the file unchanged; there is no contextual fallback either |
+| FL37 | A replaced canonical answer is refused | The import wrapper preparing a look-alike invocation returns a definition canonical execution did not produce, so verification refuses before invoking it, reaches no provider and leaves the file unchanged ([file-component.test.ts](../packages/core/tests/file-component.test.ts)); FX4 in [fixed-filesystem-components.test.ts](../packages/core/tests/fixed-filesystem-components.test.ts) reaches the fixed dispatchers directly to prove invocation authentication |
 
 ### Tier FD — `<File.Delete>`
 
@@ -12659,6 +12659,9 @@ workspaces](./workflow-workspace-spec.md) §13.
 | WAC24 | Real host crash | A `SIGKILL` while the mutation, immutable root, current-root pointer and routed journal row are written and uncommitted leaves a second connection seeing only the baseline, and a fresh process recovers the baseline filesystem, root, retained counts and journal exactly |
 | WAC25 | Committed restart | A second process reopens a run whose Workspace effects committed in a process that has ended, observes the same filesystem, current root, ordered events, event identities and event-to-root associations, and performs no recorded effect again |
 | WAC26 | Historical reconstruction | A fresh process selects an older event's root through the adapter-private materializer, invalidates the authoritative negative resolution, rebuilds its exact topology, bytes, modes, hardlinks and symbolic links from that root's retained DOFS content, and resnapshots to the selected identity |
+| WAC27 | Storage-view commit | A row written through the mutation's storage view and its filesystem bytes commit together against the root its journal event names ([workspace-effect-transaction.test.ts](../packages/workflow/tests/workspace-effect-transaction.test.ts)) |
+| WAC28 | Storage-view rollback | A refused mutation rolls back its storage-view row and filesystem bytes, retains no new root and records its failed Yield against the baseline root ([workspace-effect-transaction.test.ts](../packages/workflow/tests/workspace-effect-transaction.test.ts)) |
+| WAC29 | Mutation capability lifetime | Storage, filesystem and savepoint capabilities retained by a completed mutation refuse even while its enclosing transaction remains open before commit ([workspace-effect-transaction.test.ts](../packages/workflow/tests/workspace-effect-transaction.test.ts)) |
 
 ### Tier WTX — WorkflowRun savepoints and transaction ownership