fix(ci): drop persisted checkout credentials and pass matrix.tool through env (#658)

* fix(ci): drop persisted checkout credentials and pass matrix.tool through env

All nine actions/checkout steps left the job token in .git/config for
every later step, including bun install and bun test in CLI code a pull
request brings (zizmor artipacked). Each now sets
persist-credentials: false; no step needed the stored credential.

cli-checks expanded ${{ matrix.tool }} - a directory name discover-clis
reads from the PR's tree - into its shell script (zizmor
template-injection). It now arrives through env.

upstream-watch.yml grants issues: write to its one job rather than the
whole workflow.

The new stdlib-only test reproduces zizmor's findings on master exactly
(9 artipacked, 1 template-injection at ci.yml:227) and passes here.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* changelog: place the #658 entry under [Unreleased]

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
Co-authored-by: Mads Lorentzen <madslorentzen_17@hotmail.com>

.github/workflows/ci.yml

@@ -21,7 +21,8 @@
 # edit this workflow itself, so these guards catch accidents and casual
 # attempts, not a determined author - branch protection with required checks
 # and human review of workflow/settings diffs remain the real backstop.
-# Actions are pinned to commit SHAs; the token is read-only.
+# Actions are pinned to commit SHAs; the token is read-only, and no checkout
+# leaves it in .git/config (persist-credentials: false) for later steps to read.
 
 name: CI
 
@@ -41,6 +42,7 @@ jobs:
     steps:
       - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
         with:
+          persist-credentials: false
           fetch-depth: 0
       - uses: actions/setup-python@a26af69be951a213d495a4c3e4e4022e16d87065 # v5
         with:
@@ -56,6 +58,8 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
+        with:
+          persist-credentials: false
       - uses: actions/setup-python@a26af69be951a213d495a4c3e4e4022e16d87065 # v5
         with:
           python-version: "3.12"
@@ -70,6 +74,8 @@ jobs:
         python-version: ["3.10", "3.11", "3.12", "3.13", "3.14"]
     steps:
       - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
+        with:
+          persist-credentials: false
       - uses: actions/setup-python@a26af69be951a213d495a4c3e4e4022e16d87065 # v5
         with:
           python-version: ${{ matrix.python-version }}
@@ -89,6 +95,8 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
+        with:
+          persist-credentials: false
       - name: Probe Dependency graph availability
         id: graph
         run: |
@@ -128,6 +136,8 @@ jobs:
             container: debian:bookworm
     steps:
       - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
+        with:
+          persist-credentials: false
       - name: Install apt-packaged TeX Live (bookworm leg)
         if: matrix.leg.name == 'debian-bookworm'
         # --no-install-recommends keeps the leg lean, so the two font packages
@@ -196,6 +206,8 @@ jobs:
       tools: ${{ steps.list.outputs.tools }}
     steps:
       - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
+        with:
+          persist-credentials: false
       - id: list
         run: |
           tools=$(find .agents/skills -mindepth 3 -maxdepth 3 -path '*/cli/package.json' \
@@ -214,17 +226,23 @@ jobs:
         tool: ${{ fromJSON(needs.discover-clis.outputs.tools) }}
     steps:
       - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
+        with:
+          persist-credentials: false
       - uses: oven-sh/setup-bun@0c5077e51419868618aeaa5fe8019c62421857d6 # v2
       - run: bun install
         working-directory: .agents/skills/${{ matrix.tool }}/cli
       - run: bun run typecheck
         working-directory: .agents/skills/${{ matrix.tool }}/cli
       - name: Run fixture/mock tests when present
+        # The tool name is a directory name a pull request controls, so it
+        # reaches the shell as data through env, never as expanded script text.
+        env:
+          TOOL: ${{ matrix.tool }}
         run: |
           if find tests -type f -name '*.test.ts' | grep -q .; then
             bun test
           else
-            echo "No Bun tests found for ${{ matrix.tool }}; skipping"
+            echo "No Bun tests found for $TOOL; skipping"
           fi
         working-directory: .agents/skills/${{ matrix.tool }}/cli
 
@@ -234,6 +252,8 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
+        with:
+          persist-credentials: false
       - name: Tracked template files must keep their placeholder tokens
         run: |
           fail=0

.github/workflows/upstream-watch.yml

@@ -32,7 +32,6 @@ on:
 
 permissions:
   contents: read
-  issues: write
 
 jobs:
   triage:
@@ -41,10 +40,17 @@ jobs:
     # tests/test_upstream_triage.py so a template clone never runs it by surprise.
     if: github.repository != 'MadsLorentzen/ai-job-search'
     runs-on: ubuntu-latest
+    # Issue write is granted to this one job, not the workflow, so a job added
+    # later starts read-only.
+    permissions:
+      contents: read
+      issues: write
     steps:
       - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
         with:
           fetch-depth: 0
+          # The fetch below reads a public remote; nothing here pushes.
+          persist-credentials: false
       - uses: actions/setup-python@a26af69be951a213d495a4c3e4e4022e16d87065 # v5
         with:
           python-version: "3.12"

CHANGELOG.md

@@ -193,6 +193,21 @@ per-file diff commands.
   web search only for that last escalation step, finding the employer's own copy of the posting; company research and salary
   lookups stay out of `/rank`.
 
+### Security
+
+- **CI no longer leaves the job token in `.git/config` or expands a PR-controlled name into a
+  script** (#658, `.github/workflows/ci.yml`, `.github/workflows/upstream-watch.yml`,
+  `tests/test_workflow_hardening.py`) - all nine `actions/checkout` steps persisted the job token
+  for every later step, including `bun install` and `bun test` in CLI code a pull request brings
+  (zizmor `artipacked`); each now sets `persist-credentials: false`, which nothing needed. The
+  `cli-checks` test step expanded `${{ matrix.tool }}` - a directory name `discover-clis` reads
+  from the PR's tree - straight into its shell script (zizmor `template-injection`); it now
+  arrives through `env`. `upstream-watch.yml` grants `issues: write` to its one job instead of
+  the whole workflow, so a job added later starts read-only. The container images stay on tags:
+  the `texlive/texlive:latest` leg exists to track current TeX Live, and a digest pin without
+  automated updates would freeze both legs. The test reads the workflow text with the stdlib, so
+  it needs neither zizmor nor PyYAML.
+
 ## [1.7.3] - 2026-10-19
 
 ### Added

tests/test_workflow_hardening.py

@@ -0,0 +1,61 @@
+"""Pin the workflow settings zizmor checks, without needing zizmor or PyYAML.
+
+- Every `actions/checkout` sets `persist-credentials: false`. Otherwise the job
+  token stays in `.git/config` for every later step, including the CLI code a
+  pull request brings (`artipacked`).
+- A matrix value that comes from repository content - `cli-checks` discovers
+  `matrix.tool` from directory names, which a pull request controls - never
+  appears expanded inside a `run:` script (`template-injection`).
+"""
+import unittest
+from pathlib import Path
+
+WORKFLOWS = sorted((Path(__file__).resolve().parent.parent / ".github" / "workflows").glob("*.yml"))
+
+
+def indent(line: str) -> int:
+    return len(line) - len(line.lstrip())
+
+
+def key_indent(line: str) -> int:
+    """Column of a step's keys: two past the dash on a `- key:` line."""
+    return indent(line) + (2 if line.lstrip().startswith("- ") else 0)
+
+
+class WorkflowHardeningTests(unittest.TestCase):
+    def test_workflows_found(self):
+        self.assertTrue(WORKFLOWS)
+
+    def test_every_checkout_drops_its_credentials(self):
+        for path in WORKFLOWS:
+            lines = path.read_text(encoding="utf-8").splitlines()
+            for i, line in enumerate(lines):
+                if "uses: actions/checkout@" not in line:
+                    continue
+                keys = key_indent(line)
+                block = []
+                for following in lines[i + 1 :]:
+                    if following.strip() and indent(following) < keys:
+                        break
+                    block.append(following.strip())
+                with self.subTest(workflow=path.name, line=i + 1):
+                    self.assertIn("persist-credentials: false", block)
+
+    def test_discovered_matrix_values_stay_out_of_run_scripts(self):
+        for path in WORKFLOWS:
+            lines = path.read_text(encoding="utf-8").splitlines()
+            run_keys = None  # indent of the active `run:` key, None outside one
+            for i, line in enumerate(lines, 1):
+                if run_keys is not None and line.strip() and indent(line) <= run_keys:
+                    run_keys = None
+                stripped = line.strip()
+                if run_keys is None and stripped.startswith(("run:", "- run:")):
+                    run_keys = key_indent(line)
+                    script = stripped.split("run:", 1)[1]
+                else:
+                    script = line if run_keys is not None else ""
+                with self.subTest(workflow=path.name, line=i):
+                    self.assertNotIn("${{ matrix.tool }}", script)
+
+if __name__ == "__main__":
+    unittest.main()