diff --git a/CHANGELOG.md b/CHANGELOG.md
index 961ca7b58..4748204d8 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -111,6 +111,12 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Fixed
 
+- Attachment reads after checkpoint and Git GC recover from a stale mktree
+  process with one fresh-process retry. Broken-pipe and closed-input errors are
+  classified at the dependency protocol boundary; unrelated errors still fail.
+  This now uses published git-cas 6.5.11 and Plumbing 3.3.2; the temporary
+  source-checkout Plumbing patch is removed.
+
 - Staged-file and committed-tree path guards now reject machine-local temporary
   worktree paths as well as personal home paths. A real pre-commit regression
   verifies that cleaning the working copy cannot conceal unsafe staged content.
diff --git a/package-lock.json b/package-lock.json
index e4782dbe6..1558d997d 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -16,8 +16,8 @@
         "@flyingrobots/bijou-node": "^7.2.0",
         "@flyingrobots/bijou-tui": "^7.2.0",
         "@git-stunts/alfred": "^0.10.4",
-        "@git-stunts/git-cas": "^6.5.10",
-        "@git-stunts/plumbing": "^3.3.1",
+        "@git-stunts/git-cas": "^6.5.11",
+        "@git-stunts/plumbing": "^3.3.2",
         "@git-stunts/trailer-codec": "^2.1.1",
         "@noble/hashes": "^2.2.0",
         "cbor-x": "^1.6.0",
@@ -541,9 +541,9 @@
       "license": "Apache-2.0"
     },
     "node_modules/@git-stunts/git-cas": {
-      "version": "6.5.10",
-      "resolved": "https://registry.npmjs.org/@git-stunts/git-cas/-/git-cas-6.5.10.tgz",
-      "integrity": "sha512-JemWVMtuzqArMyxnIMBBQFMOIQ3CsvhXKfza9aIjNPxQ3MBt7J/Hm2ePr3k7Z+wtM+MO38BTGA7gzCZ/Hpld4w==",
+      "version": "6.5.11",
+      "resolved": "https://registry.npmjs.org/@git-stunts/git-cas/-/git-cas-6.5.11.tgz",
+      "integrity": "sha512-C6coWmKmOeRZ+X5nP5Ek7spwYpA5q6mgif09u9dDO0ISQQ+Hz4KVxAXrOPRRhNJzLEP74Ndbra55fxX5Cms5gw==",
       "license": "Apache-2.0",
       "dependencies": {
         "@flyingrobots/bijou": "^7.2.0",
@@ -551,7 +551,7 @@
         "@flyingrobots/bijou-tui": "^7.2.0",
         "@flyingrobots/bijou-tui-app": "^7.2.0",
         "@git-stunts/alfred": "^0.10.0",
-        "@git-stunts/plumbing": "^3.3.0",
+        "@git-stunts/plumbing": "^3.3.2",
         "@git-stunts/vault": "^1.0.1",
         "cbor-x": "^1.6.0",
         "commander": "14.0.3",
@@ -565,9 +565,9 @@
       }
     },
     "node_modules/@git-stunts/plumbing": {
-      "version": "3.3.1",
-      "resolved": "https://registry.npmjs.org/@git-stunts/plumbing/-/plumbing-3.3.1.tgz",
-      "integrity": "sha512-/pUSgdv4wE0czYywnCMJy4n4XoJud9B9gBpFcbfNQz/ZOF9WHvGuM/9T6KELcIiy2mWBNMUS+syRyLfYzL1Vmw==",
+      "version": "3.3.2",
+      "resolved": "https://registry.npmjs.org/@git-stunts/plumbing/-/plumbing-3.3.2.tgz",
+      "integrity": "sha512-yGhABF9e+o+Gc2b8L8LkXJgE0ACrJI0MbytxRyhZcHKLJfZFv9LAs8RNxv4KtIXLxQHj2StlW7T14wDk0bXWPw==",
       "license": "Apache-2.0",
       "dependencies": {
         "zod": "^3.24.1"
diff --git a/package.json b/package.json
index f891b9d8f..72cfc39e1 100644
--- a/package.json
+++ b/package.json
@@ -163,8 +163,8 @@
     "@flyingrobots/bijou-node": "^7.2.0",
     "@flyingrobots/bijou-tui": "^7.2.0",
     "@git-stunts/alfred": "^0.10.4",
-    "@git-stunts/git-cas": "^6.5.10",
-    "@git-stunts/plumbing": "^3.3.1",
+    "@git-stunts/git-cas": "^6.5.11",
+    "@git-stunts/plumbing": "^3.3.2",
     "@git-stunts/trailer-codec": "^2.1.1",
     "@noble/hashes": "^2.2.0",
     "cbor-x": "^1.6.0",
diff --git a/test/runtime/deno/deno.json b/test/runtime/deno/deno.json
index fcecdd5d0..f04ff5a42 100644
--- a/test/runtime/deno/deno.json
+++ b/test/runtime/deno/deno.json
@@ -1,8 +1,8 @@
 {
   "imports": {
     "@git-stunts/alfred": "npm:@git-stunts/alfred@^0.10.3",
-    "@git-stunts/git-cas": "npm:@git-stunts/git-cas@^6.5.10",
-    "@git-stunts/plumbing": "npm:@git-stunts/plumbing@^3.3.1",
+    "@git-stunts/git-cas": "npm:@git-stunts/git-cas@^6.5.11",
+    "@git-stunts/plumbing": "npm:@git-stunts/plumbing@^3.3.2",
     "@git-stunts/trailer-codec": "npm:@git-stunts/trailer-codec@^2.1.1",
     "@noble/hashes/blake3.js": "npm:@noble/hashes@^2.2.0/blake3.js",
     "cbor-x": "npm:cbor-x@^1.6.0",
diff --git a/test/unit/infrastructure/adapters/mktree-session-recovery.test.mjs b/test/unit/infrastructure/adapters/mktree-session-recovery.test.mjs
new file mode 100644
index 000000000..429b2b2bb
--- /dev/null
+++ b/test/unit/infrastructure/adapters/mktree-session-recovery.test.mjs
@@ -0,0 +1,104 @@
+import { describe, expect, it } from 'vitest';
+import { GitPersistenceAdapter } from '@git-stunts/git-cas';
+import { CommandSession, GitMktreeSession, GitPlumbingError, GitProtocolError } from '@git-stunts/plumbing';
+import { Readable } from 'node:stream';
+import { TextEncoder } from 'node:util';
+
+const OID = 'a'.repeat(40);
+const TREE = [`100644 blob ${'b'.repeat(40)}\tcontent`];
+
+function command(failure) {
+  let finish;
+  const finished = new Promise((resolve) => { finish = resolve; });
+  function settle({ code, terminated }) {
+    finish({ code, error: null, signal: null, stderr: '', terminated, timedOut: false });
+  }
+  return new CommandSession({
+    stdoutStream: Readable.from([new TextEncoder().encode(`${OID}\n`)]),
+    finished,
+    write: async () => { if (failure !== null) { throw failure; } },
+    closeInput: async () => { settle({ code: 0, terminated: false }); },
+    terminate: () => { settle({ code: 1, terminated: true }); },
+  });
+}
+
+function fixture(failures) {
+  let openings = 0;
+  const persistence = new GitPersistenceAdapter({
+    plumbing: {
+      openMktreeSession: async () => {
+        const failure = failures[openings] ?? null;
+        openings += 1;
+        return new GitMktreeSession(command(failure));
+      },
+    },
+    policy: { execute: (operation) => operation() },
+    sessionIdleTimeoutMs: 60_000,
+  });
+  return { persistence, openings: () => openings };
+}
+
+function brokenPipe() {
+  return Object.assign(new Error('broken pipe'), { code: 'EPIPE' });
+}
+
+describe('mktree transport recovery', () => {
+  it.each(['one tree', 'tree batch'])('reopens the process once for a broken pipe writing %s', async (mode) => {
+    const { persistence, openings } = fixture([brokenPipe()]);
+    try {
+      const result = mode === 'one tree'
+        ? await persistence.writeTree(TREE)
+        : await persistence.writeTrees([TREE]);
+      expect(result).toEqual(mode === 'one tree' ? OID : [OID]);
+      expect(openings()).toBe(2);
+    } finally {
+      await persistence.close();
+    }
+  });
+
+  it('also recovers when process completion wins the race with the next write', async () => {
+    const failure = new GitPlumbingError('input closed', 'write', { code: 'SESSION_INPUT_CLOSED' });
+    const { persistence, openings } = fixture([failure]);
+    try {
+      await expect(persistence.writeTree(TREE)).resolves.toBe(OID);
+      expect(openings()).toBe(2);
+    } finally {
+      await persistence.close();
+    }
+  });
+
+  it('reports a typed failure after two broken processes, without an unbounded retry', async () => {
+    const { persistence, openings } = fixture([brokenPipe(), brokenPipe()]);
+    try {
+      await expect(persistence.writeTree(TREE)).rejects.toBeInstanceOf(GitProtocolError);
+      expect(openings()).toBe(2);
+    } finally {
+      await persistence.close();
+    }
+  });
+
+  it('preserves other write failures and does not retry them', async () => {
+    const failure = Object.assign(new Error('permission denied'), { code: 'EACCES' });
+    const { persistence, openings } = fixture([failure]);
+    try {
+      await expect(persistence.writeTree(TREE)).rejects.toBe(failure);
+      expect(openings()).toBe(1);
+    } finally {
+      await persistence.close();
+    }
+  });
+
+  it('preserves a producer failure even when it has the same error code', async () => {
+    const failure = brokenPipe();
+    const session = new GitMktreeSession(command(null));
+    async function* entries() {
+      yield { mode: '100644', type: 'blob', oid: 'b'.repeat(40), name: 'content' };
+      throw failure;
+    }
+    try {
+      await expect(session.write(entries())).rejects.toBe(failure);
+    } finally {
+      await session.terminate();
+    }
+  });
+});
diff --git a/test/unit/scripts/dependency-hygiene.test.ts b/test/unit/scripts/dependency-hygiene.test.ts
index a26a47adc..2c9227600 100644
--- a/test/unit/scripts/dependency-hygiene.test.ts
+++ b/test/unit/scripts/dependency-hygiene.test.ts
@@ -7,9 +7,13 @@ import { z } from 'zod';
 
 const REPO_ROOT = new URL('../../../', import.meta.url);
 
-const PATCH_PACKAGE_FILES: readonly string[] = ['@git-stunts+trailer-codec+2.1.1.patch'];
+const PATCH_PACKAGE_FILES: readonly string[] = [
+  '@git-stunts+trailer-codec+2.1.1.patch',
+];
 
-const PATCH_PACKAGE_README_HEADINGS: readonly string[] = ['### `@git-stunts/trailer-codec@2.1.1`'];
+const PATCH_PACKAGE_README_HEADINGS: readonly string[] = [
+  '### `@git-stunts/trailer-codec@2.1.1`',
+];
 
 const PACKAGE_FILE_SCHEMA = z.object({
   dependencies: z.record(z.string()),
diff --git a/test/unit/scripts/v18-v17-public-read-legacy-reading-builder.test.ts b/test/unit/scripts/v18-v17-public-read-legacy-reading-builder.test.ts
index 863ba7004..83c927a95 100644
--- a/test/unit/scripts/v18-v17-public-read-legacy-reading-builder.test.ts
+++ b/test/unit/scripts/v18-v17-public-read-legacy-reading-builder.test.ts
@@ -47,9 +47,10 @@ describe('v18 v17 public-read legacy reading builder', () => {
       'alice',
     ]);
     // git-cas stamps its package version into the manifest formatVersion, so dependency
-    // bumps intentionally advance this migration-reading golden handle.
+    // bumps intentionally advance this migration-reading golden handle and manifestHash.
+    // Verified against published git-cas 6.5.11 with unchanged payload bytes.
     expect(reading.facts.find((fact) => fact.factKey === 'node:alpha:_content')?.value)
-      .toBe('git-cas:1:asset:manifest-tree:cbor:sha1:09e785fbd98adf5c00f250598d3a92b0e3e75a33');
+      .toBe('git-cas:1:asset:manifest-tree:cbor:sha1:2b67e47826ccb797a7441019756abc3e697792d3');
   });
 
   it('fails closed when a restored v17 writer ref drifts after restore', async () => {