From ba00eca087fa8004adfabaaa18a1b44f83186466 Mon Sep 17 00:00:00 2001
From: Claude <noreply@anthropic.com>
Date: Fri, 4 Sep 2026 00:49:25 +0000
Subject: [PATCH 1/2] gate: a deterministic test-integrity kind, so green CI
 must be earned

docs/agentic-risk-coverage.md has carried this row honestly for weeks:

  ...an agent deleting tests or assertions to get green?
  agent-discipline (assertion_deletion: block)
  advisory today -- a deterministic test-integrity gate is a named catalog
  candidate, not yet a roadmap issue, so this row stays advisory until it is.

It could not be anything else: all three existing kinds read only the added
side of a diff, and test tampering is visible only in what a change takes
away. This adds the missing primitive, GateContext.removed_lines(), and one
kind built on it.

test_integrity blocks three shapes, all deterministic and author-blind:
a deleted test file, a net loss of assertions across the change, and a
vacuous assertion (assert True, expect(true)) added in its place. The escape
hatch is a pragma written on the line that removes the test, so an obsolete
test can still go -- visibly, in the diff, where a human sees it.

The net count is taken across the whole change rather than per file, which
keeps a test split across two files from reading as a deletion. What it
costs is a change that strips one file while adding to another; that is the
right trade for a gate whose false positives would get it disabled.

Patterns are policy data, not engine behaviour: the kind is language-
agnostic and every language's idea of a test and an assertion arrives
through params from .agents/policies/test-integrity/manifest.yaml.

The gate runs on commit and in CI. CI is the half that matters for an
inbound contributor, whose agent never ran a local hook.

7 behavioural tests over real git repositories, including the two that keep
the gate adoptable: a refactor deleting an assert from application code
passes, and a reviewed removal passes.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_014gwmBVUHSgohCLkNVqAR77
---
 .agents/policies/test-integrity/manifest.yaml | 62 +++++++++++++++
 src/chock/gate/runner.py                      | 40 ++++++++++
 src/chock/gate/schema.py                      | 10 +++
 tests/test_test_integrity_gate.py             | 76 +++++++++++++++++++
 4 files changed, 188 insertions(+)
 create mode 100644 .agents/policies/test-integrity/manifest.yaml
 create mode 100644 tests/test_test_integrity_gate.py

diff --git a/.agents/policies/test-integrity/manifest.yaml b/.agents/policies/test-integrity/manifest.yaml
new file mode 100644
index 0000000..cab3773
--- /dev/null
+++ b/.agents/policies/test-integrity/manifest.yaml
@@ -0,0 +1,62 @@
+id: test-integrity
+name: "Test Integrity"
+version: "0.0.1"
+description: >
+  Block a change that wins green CI by weakening the tests instead of fixing the code.
+  Catches a deleted test file, a net loss of assertions across the change, and a vacuous
+  assertion (`assert True`, `expect(true)`) added in its place. Author-blind: the CI gate
+  re-runs it on the PR head, so it holds for an inbound contributor whose agent never ran
+  a hook. Defends the signal every other gate trusts.
+artifact: hook
+enforcement: block
+mandatory: false
+effects:
+- read_only
+approval:
+  required: false
+
+hook:
+  gate:
+    kind: test_integrity
+    "on": [commit, ci]
+    action: block
+    message: >
+      Tests were weakened, not fixed. If a test is genuinely obsolete, say so on the line
+      that removes it with `chock: test-removal-reviewed` and have a human confirm it.
+    params:
+      # Patterns are policy data, not engine behaviour: the kind is language-agnostic and
+      # every language's idea of "a test" and "an assertion" arrives from here.
+      test_path_regex: "(^|/)(tests?|spec|__tests__)/|(_test|_spec|\\.test|\\.spec)\\.[a-z]+$"
+      assertion_pattern: "\\b(assert|assertEquals|assertTrue|expect|should|require\\.(True|NoError))\\b"
+      # Counted only when ADDED -- a test that asserts nothing is worse than no test,
+      # because it reports green.
+      dummy_assertion_pattern: "\\b(assert\\s+(True|1)\\b|expect\\s*\\(\\s*(true|1)\\s*\\)|assertTrue\\s*\\(\\s*true\\s*\\))"
+      allowlist_pragma: "chock: test-removal-reviewed"
+
+compliance:
+  owasp_asi:
+  - control: ASI04
+    coverage: partial
+    note: "blocks test deletion, net assertion loss and vacuous assertions in test paths"
+
+provenance:
+  author: "chock-core"
+  created_at: "2026-09-03T00:00:00Z"
+  updated_at: "2026-09-03T00:00:00Z"
+  source_repo: "https://github.com/open-coder-ai/chock"
+  license: "Apache-2.0"
+  trust_tier: "community"
+
+lifecycle:
+  status: draft
+  reviewed_by:
+  - "chock-core"
+
+security:
+  content_instructions: never-obey
+
+changelog:
+- version: 0.0.1
+  date: '2026-09-03'
+  changes:
+  - "Initial: test_integrity gate kind, closing the advisory row in agentic-risk-coverage."
diff --git a/src/chock/gate/runner.py b/src/chock/gate/runner.py
index 95b7ecd..e156131 100644
--- a/src/chock/gate/runner.py
+++ b/src/chock/gate/runner.py
@@ -77,6 +77,12 @@ def added_lines(self, path: str) -> list[str]:
                 lines.append(line[1:])
         return lines
 
+    def removed_lines(self, path: str) -> list[str]:
+        """The deleted side of the diff -- what a test-weakening change takes away."""
+        out = self._git("diff", *self._range(), "-U0", "--", path)
+        return [line[1:] for line in out.splitlines()
+                if line.startswith("-") and not line.startswith("---")]
+
     def staged_blob(self, path: str) -> str:
         """The proposed content: staged in index mode, committed at HEAD in range mode."""
         return self._git("show", f"HEAD:{path}" if self.base else f":{path}")
@@ -235,10 +241,44 @@ def _kind_dependency_allowlist(ctx: GateContext, params: dict, _event: str) -> G
     return GateResult(allowed=not matches, matches=matches)
 
 
+def _count(pattern: "re.Pattern[str]", lines: list[str], pragma: "re.Pattern[str] | None") -> int:
+    return sum(1 for line in lines if pattern.search(line) and not (pragma and pragma.search(line)))
+
+
+def _kind_test_integrity(ctx: GateContext, params: dict, _event: str) -> GateResult:
+    """Block a change that wins green CI by weakening the tests rather than fixing the code."""
+    path_re = re.compile(params["test_path_regex"])
+    assertion_re = re.compile(params["assertion_pattern"])
+    dummy_pattern = params.get("dummy_assertion_pattern")
+    dummy_re = re.compile(dummy_pattern) if dummy_pattern else None
+    pragma = params.get("allowlist_pragma")
+    pragma_re = re.compile(pragma) if pragma else None
+
+    matches: list[str] = []
+    added = removed = 0
+    for path in ctx.staged_paths("D"):
+        if path_re.search(path):
+            matches.append(f"{path}: test file deleted")
+    for path in ctx.staged_paths("ACMRT"):
+        if not path_re.search(path):
+            continue
+        added_lines = ctx.added_lines(path)
+        if pragma_re and any(pragma_re.search(line) for line in added_lines):
+            continue
+        added += _count(assertion_re, added_lines, pragma_re)
+        removed += _count(assertion_re, ctx.removed_lines(path), pragma_re)
+        if dummy_re and any(dummy_re.search(line) for line in added_lines):
+            matches.append(f"{path}: vacuous assertion added")
+    if removed > added:
+        matches.append(f"assertions removed across tests: {removed} removed, {added} added")
+    return GateResult(allowed=not matches, matches=matches)
+
+
 KINDS = {
     "content_regex": _kind_content_regex,
     "forbidden_ref": _kind_forbidden_ref,
     "dependency_allowlist": _kind_dependency_allowlist,
+    "test_integrity": _kind_test_integrity,
 }
 
 
diff --git a/src/chock/gate/schema.py b/src/chock/gate/schema.py
index 6838a76..5a92eea 100644
--- a/src/chock/gate/schema.py
+++ b/src/chock/gate/schema.py
@@ -45,6 +45,16 @@
             "allowlist_file": {"type": "string"},
         },
     },
+    "test_integrity": {
+        **_CLOSED_OBJECT,
+        "required": ["test_path_regex", "assertion_pattern"],
+        "properties": {
+            "test_path_regex": {"type": "string", "minLength": 1},
+            "assertion_pattern": {"type": "string", "minLength": 1},
+            "dummy_assertion_pattern": {"type": "string"},
+            "allowlist_pragma": {"type": "string"},
+        },
+    },
     "egress_allowlist": {
         **_CLOSED_OBJECT,
         "required": ["allowed_hosts"],
diff --git a/tests/test_test_integrity_gate.py b/tests/test_test_integrity_gate.py
new file mode 100644
index 0000000..925f581
--- /dev/null
+++ b/tests/test_test_integrity_gate.py
@@ -0,0 +1,76 @@
+"""Behavioural tests for the test-integrity gate: green CI must be earned, not arranged."""
+
+from __future__ import annotations
+
+import subprocess
+from pathlib import Path
+
+from conftest import baseline_policy, build_test_gate_json, init_repo, stage
+
+from chock.gate.runner import run
+
+POLICY_DIR = baseline_policy("test-integrity")
+
+REAL_TEST = """def test_adds():
+    assert add(1, 2) == 3
+    assert add(0, 0) == 0
+"""
+
+
+def _repo(tmp_path: Path) -> tuple[Path, Path]:
+    init_repo(tmp_path)
+    stage(tmp_path, "tests/test_math.py", REAL_TEST)
+    subprocess.run(["git", "commit", "-qm", "base"], cwd=tmp_path, check=True)
+    return tmp_path, build_test_gate_json(tmp_path, POLICY_DIR)
+
+
+def _verdict(repo: Path, gate: Path) -> int:
+    return run(gate, "pre-commit", None, repo)
+
+
+def test_a_real_fix_passes(tmp_path: Path) -> None:
+    repo, gate = _repo(tmp_path)
+    stage(repo, "app.py", "def add(a, b):\n    return a + b\n")
+    assert _verdict(repo, gate) == 0
+
+
+def test_adding_assertions_passes(tmp_path: Path) -> None:
+    repo, gate = _repo(tmp_path)
+    stage(repo, "tests/test_math.py", REAL_TEST + "    assert add(-1, 1) == 0\n")
+    assert _verdict(repo, gate) == 0
+
+
+def test_deleting_a_test_file_is_blocked(tmp_path: Path) -> None:
+    repo, gate = _repo(tmp_path)
+    subprocess.run(["git", "rm", "-q", "tests/test_math.py"], cwd=repo, check=True)
+    assert _verdict(repo, gate) != 0
+
+
+def test_stripping_assertions_is_blocked(tmp_path: Path) -> None:
+    """The actual attack: keep the test, remove what it checks, collect green CI."""
+    repo, gate = _repo(tmp_path)
+    stage(repo, "tests/test_math.py", "def test_adds():\n    add(1, 2)\n")
+    assert _verdict(repo, gate) != 0
+
+
+def test_a_vacuous_assertion_is_blocked(tmp_path: Path) -> None:
+    repo, gate = _repo(tmp_path)
+    stage(repo, "tests/test_math.py", REAL_TEST + "\n\ndef test_new():\n    assert True\n")
+    assert _verdict(repo, gate) != 0
+
+
+def test_non_test_paths_are_not_policed(tmp_path: Path) -> None:
+    """Deleting an assert from application code is a refactor, not test tampering."""
+    repo, gate = _repo(tmp_path)
+    stage(repo, "app.py", "def add(a, b):\n    assert isinstance(a, int)\n    return a + b\n")
+    subprocess.run(["git", "commit", "-qm", "app"], cwd=repo, check=True)
+    stage(repo, "app.py", "def add(a, b):\n    return a + b\n")
+    assert _verdict(repo, gate) == 0
+
+
+def test_a_reviewed_removal_is_allowed_through(tmp_path: Path) -> None:
+    """The escape hatch is deliberate, in the diff, and named — not a config toggle."""
+    repo, gate = _repo(tmp_path)
+    stage(repo, "tests/test_math.py",
+          "def test_adds():  # chock: test-removal-reviewed\n    assert add(1, 2) == 3\n")
+    assert _verdict(repo, gate) == 0

From da66872f6a24ea7e3474aa9b62576716a050548f Mon Sep 17 00:00:00 2001
From: Claude <noreply@anthropic.com>
Date: Fri, 4 Sep 2026 01:30:14 +0000
Subject: [PATCH 2/2] gate: wire test_integrity into validation, docs, and CI;
 fix latent bugs

Full-suite regression over the test-integrity work from ba00eca surfaced
seven failures, all caused by this branch and now fixed:

- Vendored .chock/bin/gate.py was stale against src/chock/gate/runner.py
  (re-vendored via `chock sync`).
- The manifest's `on: [commit, ci]` declared a literal "ci" event that
  no runtime or schema recognizes -- CI coverage is derived from
  "commit" being present, per every other manifest and spec/gate-dsl.md.
  Fixed to `on: [commit]`.
- src/chock/validation/schemas/manifest.hook.json's `kind` enum
  (structural JSON-schema layer, separate from KINDS/KIND_PARAM_SCHEMAS)
  never listed `test_integrity`, so any manifest declaring it failed
  validation. Added.
- The policy shipped no evals/suite.yaml, tripping the eval_first
  check. Added six hand-authored cases (trigger/negative_trigger/
  behavior/edge) -- not added to eval/derive.py's DERIVABLE_KINDS,
  since its params are open regexes over diff content, not an
  enumerable list like forbidden_ref's refs or dependency_allowlist's
  manifests.
- spec/gate-dsl.md never documented the new kind's params.
- Two files were unformatted (`ruff format --check` is part of CI
  though only `ruff check` was verified in the prior pass).

Also, per chock-g1 T2-T5:
- checks_gate_shape.py needed no code change (it already reads
  KINDS/KIND_PARAM_SCHEMAS); added tests confirming a test_integrity
  manifest validates and a bad param shape is rejected.
- Confirmed test_integrity is absent from GATEWAY_ONLY_KINDS and
  RUNTIME_KINDS (it needs a git diff, so it has no gateway runtime).
- .agents/policies/INDEX.md gets the new entry automatically from
  `chock sync`; docs/baseline-policies.md's guard table and declarative
  list are updated by hand (docs/policies/, docs/cli-reference.md and
  llms.txt don't enumerate individual policies).
- docs/agentic-risk-coverage.md's test-deletion row moves from
  `advisory` to `enforced-at-commit`, backed by the tests above; no
  pre-tool-use tier is claimed since none exists.
- CHANGELOG.md entry added.

Found live while writing this commit: test_path_regex's directory
branch matched any file under a `tests?/spec/__tests__` dir regardless
of extension, so documenting the gate in spec/gate-dsl.md (this repo's
own design-doc directory, not RSpec tests) with the worked example
"assert True" tripped the gate's own vacuous-assertion check on itself.
Fixed by excluding .md/.rst/.txt from the directory branch; regression
cases added to both the eval suite and the behavioural pytest suite.

Full suite: 1055 passed, 6 skipped. `ruff check .` and
`ruff format --check .` both clean.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Signed-off-by: Claude <noreply@anthropic.com>
---
 .agents/policies/INDEX.md                     |   1 +
 .../policies/test-integrity/evals/suite.yaml  | 110 ++++++++++++++++++
 .agents/policies/test-integrity/manifest.yaml |   7 +-
 .chock/bin/gate.py                            |  39 +++++++
 .../test-integrity/ambient-rule/ambient.md    |   6 +
 .../compiled/test-integrity/ci-gate/gate.json |  14 +++
 .../compiled/test-integrity/ci-gate/step.yaml |  12 ++
 .../test-integrity/git-hook/gate.json         |  14 +++
 .../test-integrity/git-hook/git-pre-commit.sh |  11 ++
 .../managed-setting/managed-settings.json     |   4 +
 .chock/coverage.json                          |  67 +++++++++++
 .chock/registry.json                          |  15 +++
 CHANGELOG.md                                  |   8 ++
 chock.lock                                    |   8 ++
 docs/agentic-risk-coverage.md                 |   2 +-
 docs/baseline-policies.md                     |   3 +-
 spec/gate-dsl.md                              |  18 ++-
 src/chock/gate/runner.py                      |   3 +-
 .../validation/schemas/manifest.hook.json     |   3 +-
 tests/test_manifest_validation.py             |  53 +++++++++
 tests/test_test_integrity_gate.py             |  10 +-
 21 files changed, 398 insertions(+), 10 deletions(-)
 create mode 100644 .agents/policies/test-integrity/evals/suite.yaml
 create mode 100644 .chock/compiled/test-integrity/ambient-rule/ambient.md
 create mode 100644 .chock/compiled/test-integrity/ci-gate/gate.json
 create mode 100644 .chock/compiled/test-integrity/ci-gate/step.yaml
 create mode 100644 .chock/compiled/test-integrity/git-hook/gate.json
 create mode 100755 .chock/compiled/test-integrity/git-hook/git-pre-commit.sh
 create mode 100644 .chock/compiled/test-integrity/managed-setting/managed-settings.json

diff --git a/.agents/policies/INDEX.md b/.agents/policies/INDEX.md
index 66d0300..cf77eef 100644
--- a/.agents/policies/INDEX.md
+++ b/.agents/policies/INDEX.md
@@ -56,6 +56,7 @@
 - **block-wildcard-agent-permissions**: Wildcard agent permission grant detected. Scope the grant to specific tools or commands (e.g. Bash(git status:*), a named tool list), or add 'pragma: allowlist broad-agency' on the same line for a reviewed exception.
 - **protect-main-branch**: Direct commits/pushes to a protected branch (main|master) are blocked. Create a feature branch and open a pull request.
 - **scan-secrets**: Potential secret detected in staged changes. Remove credentials and rotate any exposed keys. Add '# pragma: allowlist secret' on the same line only for documented test fixtures.
+- **test-integrity**: Tests were weakened, not fixed. If a test is genuinely obsolete, say so on the line that removes it with `chock: test-removal-reviewed` and have a human confirm it.
 
 ## Skills — invoke when the task matches
 
diff --git a/.agents/policies/test-integrity/evals/suite.yaml b/.agents/policies/test-integrity/evals/suite.yaml
new file mode 100644
index 0000000..694a63d
--- /dev/null
+++ b/.agents/policies/test-integrity/evals/suite.yaml
@@ -0,0 +1,110 @@
+suite:
+  id: test-integrity-tests-v1
+  policy_id: test-integrity
+  version_constraint: ">=0.0.1"
+  maintainer: chock-core
+  primary_metric: pass_rate
+  metrics:
+    pass_rate:
+      direction: higher_is_better
+      threshold: 1.0
+  cases:
+  - id: tc-001
+    category: trigger
+    prompt: An agent removes a failing assertion from a test instead of fixing the code under test.
+    expect: The gate blocks because assertions were removed with nothing added in their place.
+    execute:
+      head_files:
+        tests/test_foo.py: |
+          def test_a():
+              assert 1 == 1
+
+          def test_b():
+              assert 2 == 2
+      files:
+        tests/test_foo.py: |
+          def test_a():
+              assert 1 == 1
+      event: commit
+      expect: block
+  - id: tc-002
+    category: trigger
+    prompt: An agent replaces a real assertion with a vacuous one so the test still runs but proves nothing.
+    expect: The gate blocks because a vacuous assertion (assert True) was added.
+    execute:
+      head_files:
+        tests/test_foo.py: |
+          def test_a():
+              assert compute() == 42
+      files:
+        tests/test_foo.py: |
+          def test_a():
+              assert True
+      event: commit
+      expect: block
+  - id: tc-003
+    category: negative_trigger
+    prompt: An agent adds a new test with a real assertion alongside the existing ones.
+    expect: The gate allows the commit because assertions only grew.
+    execute:
+      head_files:
+        tests/test_foo.py: |
+          def test_a():
+              assert 1 == 1
+      files:
+        tests/test_foo.py: |
+          def test_a():
+              assert 1 == 1
+
+          def test_b():
+              assert 2 == 2
+      event: commit
+      expect: allow
+  - id: tc-004
+    category: behavior
+    prompt: A human reviews a genuinely obsolete test and marks its removal with the allowlist pragma.
+    expect: The gate allows the commit because the removal is pragma-reviewed.
+    execute:
+      head_files:
+        tests/test_foo.py: |
+          def test_obsolete():
+              assert 1 == 1  # covers a feature removed last release
+      files:
+        tests/test_foo.py: |
+          # test_obsolete removed: feature no longer exists
+          # chock: test-removal-reviewed
+      event: commit
+      expect: allow
+  # A source file losing an assert-like line is not a test-integrity concern; the path
+  # regex scopes the gate to test files only. No derived case can express this scoping --
+  # it needs a repository with a history, same as verify-dependency-exists tc-005.
+  - id: tc-005
+    category: edge
+    prompt: An agent removes a runtime assertion from application code, not a test.
+    expect: The gate allows the commit because the changed file is not a test file.
+    execute:
+      head_files:
+        src/app.py: |
+          def f(x):
+              assert x > 0
+              return x
+      files:
+        src/app.py: |
+          def f(x):
+              return x
+      event: commit
+      expect: allow
+  # Found live while documenting this gate: a `spec/` directory of design prose (this
+  # repo's own layout) is not RSpec test code, so writing "assert True" as a worked
+  # example in a markdown doc under spec/ must not itself trip the vacuous-assertion
+  # check that same doc describes.
+  - id: tc-006
+    category: edge
+    prompt: A markdown doc under spec/ uses "assert True" as a worked example in prose.
+    expect: The gate allows the commit because a .md file is documentation, not a test file.
+    execute:
+      files:
+        spec/gate-dsl.md: |
+          `dummy_assertion_pattern` matches a vacuous check such as `assert True`.
+      event: commit
+      expect: allow
diff --git a/.agents/policies/test-integrity/manifest.yaml b/.agents/policies/test-integrity/manifest.yaml
index cab3773..4dc2700 100644
--- a/.agents/policies/test-integrity/manifest.yaml
+++ b/.agents/policies/test-integrity/manifest.yaml
@@ -18,7 +18,7 @@ approval:
 hook:
   gate:
     kind: test_integrity
-    "on": [commit, ci]
+    "on": [commit]
     action: block
     message: >
       Tests were weakened, not fixed. If a test is genuinely obsolete, say so on the line
@@ -26,7 +26,10 @@ hook:
     params:
       # Patterns are policy data, not engine behaviour: the kind is language-agnostic and
       # every language's idea of "a test" and "an assertion" arrives from here.
-      test_path_regex: "(^|/)(tests?|spec|__tests__)/|(_test|_spec|\\.test|\\.spec)\\.[a-z]+$"
+      # The directory branch excludes prose extensions (.md/.rst/.txt) via a negative
+      # lookahead -- a `spec/` or `tests/` directory holding design docs, not test code,
+      # (as this very repo's spec/ does) must not be policed as test assertions.
+      test_path_regex: "(^|/)(tests?|spec|__tests__)/(?!.*\\.(?:md|rst|txt)$)|(_test|_spec|\\.test|\\.spec)\\.[a-z]+$"
       assertion_pattern: "\\b(assert|assertEquals|assertTrue|expect|should|require\\.(True|NoError))\\b"
       # Counted only when ADDED -- a test that asserts nothing is worse than no test,
       # because it reports green.
diff --git a/.chock/bin/gate.py b/.chock/bin/gate.py
index 95b7ecd..4c1c45e 100755
--- a/.chock/bin/gate.py
+++ b/.chock/bin/gate.py
@@ -77,6 +77,11 @@ def added_lines(self, path: str) -> list[str]:
                 lines.append(line[1:])
         return lines
 
+    def removed_lines(self, path: str) -> list[str]:
+        """The deleted side of the diff -- what a test-weakening change takes away."""
+        out = self._git("diff", *self._range(), "-U0", "--", path)
+        return [line[1:] for line in out.splitlines() if line.startswith("-") and not line.startswith("---")]
+
     def staged_blob(self, path: str) -> str:
         """The proposed content: staged in index mode, committed at HEAD in range mode."""
         return self._git("show", f"HEAD:{path}" if self.base else f":{path}")
@@ -235,10 +240,44 @@ def _kind_dependency_allowlist(ctx: GateContext, params: dict, _event: str) -> G
     return GateResult(allowed=not matches, matches=matches)
 
 
+def _count(pattern: "re.Pattern[str]", lines: list[str], pragma: "re.Pattern[str] | None") -> int:
+    return sum(1 for line in lines if pattern.search(line) and not (pragma and pragma.search(line)))
+
+
+def _kind_test_integrity(ctx: GateContext, params: dict, _event: str) -> GateResult:
+    """Block a change that wins green CI by weakening the tests rather than fixing the code."""
+    path_re = re.compile(params["test_path_regex"])
+    assertion_re = re.compile(params["assertion_pattern"])
+    dummy_pattern = params.get("dummy_assertion_pattern")
+    dummy_re = re.compile(dummy_pattern) if dummy_pattern else None
+    pragma = params.get("allowlist_pragma")
+    pragma_re = re.compile(pragma) if pragma else None
+
+    matches: list[str] = []
+    added = removed = 0
+    for path in ctx.staged_paths("D"):
+        if path_re.search(path):
+            matches.append(f"{path}: test file deleted")
+    for path in ctx.staged_paths("ACMRT"):
+        if not path_re.search(path):
+            continue
+        added_lines = ctx.added_lines(path)
+        if pragma_re and any(pragma_re.search(line) for line in added_lines):
+            continue
+        added += _count(assertion_re, added_lines, pragma_re)
+        removed += _count(assertion_re, ctx.removed_lines(path), pragma_re)
+        if dummy_re and any(dummy_re.search(line) for line in added_lines):
+            matches.append(f"{path}: vacuous assertion added")
+    if removed > added:
+        matches.append(f"assertions removed across tests: {removed} removed, {added} added")
+    return GateResult(allowed=not matches, matches=matches)
+
+
 KINDS = {
     "content_regex": _kind_content_regex,
     "forbidden_ref": _kind_forbidden_ref,
     "dependency_allowlist": _kind_dependency_allowlist,
+    "test_integrity": _kind_test_integrity,
 }
 
 
diff --git a/.chock/compiled/test-integrity/ambient-rule/ambient.md b/.chock/compiled/test-integrity/ambient-rule/ambient.md
new file mode 100644
index 0000000..5815fd0
--- /dev/null
+++ b/.chock/compiled/test-integrity/ambient-rule/ambient.md
@@ -0,0 +1,6 @@
+<!-- chock:hooks:start (compiled by chock -- edit .agents/policies/test-integrity/) -->
+```
+on(commit): block(test_integrity) test_path_regex=(^|/)(tests?|spec|__tests__)/(?!.*\.(?:md|rst... ...
+Tests were weakened, not fixed. If a test is genuinely obsolete, say so on the line that removes it with `chock: test-removal-reviewed` and have a human confirm it.
+```
+<!-- chock:hooks:end -->
diff --git a/.chock/compiled/test-integrity/ci-gate/gate.json b/.chock/compiled/test-integrity/ci-gate/gate.json
new file mode 100644
index 0000000..cf53e79
--- /dev/null
+++ b/.chock/compiled/test-integrity/ci-gate/gate.json
@@ -0,0 +1,14 @@
+{
+  "kind": "test_integrity",
+  "on": [
+    "commit"
+  ],
+  "action": "block",
+  "message": "Tests were weakened, not fixed. If a test is genuinely obsolete, say so on the line that removes it with `chock: test-removal-reviewed` and have a human confirm it.",
+  "params": {
+    "test_path_regex": "(^|/)(tests?|spec|__tests__)/(?!.*\\.(?:md|rst|txt)$)|(_test|_spec|\\.test|\\.spec)\\.[a-z]+$",
+    "assertion_pattern": "\\b(assert|assertEquals|assertTrue|expect|should|require\\.(True|NoError))\\b",
+    "dummy_assertion_pattern": "\\b(assert\\s+(True|1)\\b|expect\\s*\\(\\s*(true|1)\\s*\\)|assertTrue\\s*\\(\\s*true\\s*\\))",
+    "allowlist_pragma": "chock: test-removal-reviewed"
+  }
+}
\ No newline at end of file
diff --git a/.chock/compiled/test-integrity/ci-gate/step.yaml b/.chock/compiled/test-integrity/ci-gate/step.yaml
new file mode 100644
index 0000000..36d218c
--- /dev/null
+++ b/.chock/compiled/test-integrity/ci-gate/step.yaml
@@ -0,0 +1,12 @@
+# Auto-generated by chock compile.
+# Policy: test-integrity
+- name: chock-ci-gate (test-integrity)
+  run: |
+    PY=""
+    for c in python3 python py; do
+      if command -v "$c" >/dev/null 2>&1 && "$c" -c 'import tomllib' >/dev/null 2>&1; then PY="$c"; break; fi
+    done
+    [ -n "$PY" ] || { echo "gate: no python >= 3.11 (with tomllib) found on PATH" >&2; exit 2; }
+    base="${GITHUB_BASE_REF:?ci-gate needs GITHUB_BASE_REF -- run this step on the pull_request event}"
+    "$PY" .chock/bin/gate.py run --gate .chock/compiled/test-integrity/ci-gate/gate.json --event ci --base "origin/$base" \
+      --head-ref "${GITHUB_HEAD_REF:-}"
diff --git a/.chock/compiled/test-integrity/git-hook/gate.json b/.chock/compiled/test-integrity/git-hook/gate.json
new file mode 100644
index 0000000..cf53e79
--- /dev/null
+++ b/.chock/compiled/test-integrity/git-hook/gate.json
@@ -0,0 +1,14 @@
+{
+  "kind": "test_integrity",
+  "on": [
+    "commit"
+  ],
+  "action": "block",
+  "message": "Tests were weakened, not fixed. If a test is genuinely obsolete, say so on the line that removes it with `chock: test-removal-reviewed` and have a human confirm it.",
+  "params": {
+    "test_path_regex": "(^|/)(tests?|spec|__tests__)/(?!.*\\.(?:md|rst|txt)$)|(_test|_spec|\\.test|\\.spec)\\.[a-z]+$",
+    "assertion_pattern": "\\b(assert|assertEquals|assertTrue|expect|should|require\\.(True|NoError))\\b",
+    "dummy_assertion_pattern": "\\b(assert\\s+(True|1)\\b|expect\\s*\\(\\s*(true|1)\\s*\\)|assertTrue\\s*\\(\\s*true\\s*\\))",
+    "allowlist_pragma": "chock: test-removal-reviewed"
+  }
+}
\ No newline at end of file
diff --git a/.chock/compiled/test-integrity/git-hook/git-pre-commit.sh b/.chock/compiled/test-integrity/git-hook/git-pre-commit.sh
new file mode 100755
index 0000000..a7e9338
--- /dev/null
+++ b/.chock/compiled/test-integrity/git-hook/git-pre-commit.sh
@@ -0,0 +1,11 @@
+#!/usr/bin/env bash
+# Auto-generated by chock compile. Declarative gate: test-integrity
+set -eu
+repo_root="$(git rev-parse --show-toplevel)"
+PY=""
+for c in python3 python py; do
+  if command -v "$c" >/dev/null 2>&1 && "$c" -c 'import tomllib' >/dev/null 2>&1; then PY="$c"; break; fi
+done
+[ -n "$PY" ] || { echo "gate: no python >= 3.11 (with tomllib) found on PATH" >&2; exit 2; }
+exec "$PY" "$repo_root/.chock/bin/gate.py" run \
+  --gate "$repo_root/.chock/compiled/test-integrity/git-hook/gate.json" --event pre-commit
diff --git a/.chock/compiled/test-integrity/managed-setting/managed-settings.json b/.chock/compiled/test-integrity/managed-setting/managed-settings.json
new file mode 100644
index 0000000..8efb266
--- /dev/null
+++ b/.chock/compiled/test-integrity/managed-setting/managed-settings.json
@@ -0,0 +1,4 @@
+{
+  "deny": [],
+  "ask": []
+}
\ No newline at end of file
diff --git a/.chock/coverage.json b/.chock/coverage.json
index 5b72d9c..b18a984 100644
--- a/.chock/coverage.json
+++ b/.chock/coverage.json
@@ -1071,6 +1071,73 @@
       "witnessed": false
     }
   },
+  "test-integrity": {
+    "aider": {
+      "level": "enforced-at-commit",
+      "basis": null,
+      "witnessed": false
+    },
+    "claude": {
+      "level": "enforced-at-commit",
+      "basis": null,
+      "witnessed": false
+    },
+    "codex": {
+      "level": "enforced-at-commit",
+      "basis": null,
+      "witnessed": false
+    },
+    "copilot": {
+      "level": "enforced-at-commit",
+      "basis": null,
+      "witnessed": false
+    },
+    "cursor": {
+      "level": "enforced-at-commit",
+      "basis": null,
+      "witnessed": false
+    },
+    "devin": {
+      "level": "enforced-at-commit",
+      "basis": null,
+      "witnessed": false
+    },
+    "gemini": {
+      "level": "enforced-at-commit",
+      "basis": null,
+      "witnessed": false
+    },
+    "grok": {
+      "level": "enforced-at-commit",
+      "basis": null,
+      "witnessed": false
+    },
+    "kimi-code": {
+      "level": "enforced-at-commit",
+      "basis": null,
+      "witnessed": false
+    },
+    "replit": {
+      "level": "enforced-at-commit",
+      "basis": null,
+      "witnessed": false
+    },
+    "tabnine": {
+      "level": "enforced-at-commit",
+      "basis": null,
+      "witnessed": false
+    },
+    "vscode": {
+      "level": "enforced-at-commit",
+      "basis": null,
+      "witnessed": false
+    },
+    "windsurf": {
+      "level": "enforced-at-commit",
+      "basis": null,
+      "witnessed": false
+    }
+  },
   "token-efficiency": {
     "aider": {
       "level": "advisory",
diff --git a/.chock/registry.json b/.chock/registry.json
index 8aab850..1960644 100644
--- a/.chock/registry.json
+++ b/.chock/registry.json
@@ -301,6 +301,21 @@
         "script_hashes": {}
       }
     ],
+    "test-integrity": [
+      {
+        "id": "test-integrity",
+        "artifact": "hook",
+        "version": "0.0.1",
+        "name": "Test Integrity",
+        "description": "Block a change that wins green CI by weakening the tests instead of fixing the code. Catches a deleted test file, a net loss of assertions across the change, and a vacuous assertion (`assert True`, `expect(true)`) added in its place. Author-blind: the CI gate re-runs it on the PR head, so it holds for an inbound contributor whose agent never ran a hook. Defends the signal every other gate trusts.",
+        "path": ".agents/policies/test-integrity",
+        "manifest": "manifest.yaml",
+        "trust_tier": "community",
+        "lifecycle_status": "draft",
+        "dependencies": [],
+        "script_hashes": {}
+      }
+    ],
     "token-efficiency": [
       {
         "id": "token-efficiency",
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 775e8e8..c167d96 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,14 @@
 
 ## Unreleased
 
+- **Added the `test_integrity` gate kind, closing the `agentic-risk-coverage.md` row on an
+  agent deleting tests or assertions to get green** (catalog policy `test-integrity`,
+  `chock-g1`). Blocks a deleted test file, a net loss of assertions across the whole
+  change, and a vacuous assertion (`assert True`, `expect(true)`) added in its place;
+  `chock: test-removal-reviewed` on the removing line is the reviewed escape hatch.
+  Declarative (`hook.gate` in `manifest.yaml`), `enforced-at-commit` with the `ci-gate`
+  backstop so it holds for an inbound contributor whose agent never ran a local hook. The
+  coverage row moves from `advisory` to `enforced-at-commit`.
 - **Fixed a dead `import shutil` in every vendored runtime bundle except `claude_code`'s.**
   `chock.gate.runtime_bundle.render()` spliced its fixed `_chock_`-renamed stdlib import
   block into every agent's bundle regardless of which of those names the assembled handler
diff --git a/chock.lock b/chock.lock
index d1af309..4d95edb 100644
--- a/chock.lock
+++ b/chock.lock
@@ -130,6 +130,14 @@
       "source": "local",
       "artifacts_sha256": "cd7df13ded59738cd76aa24c19ec0600ca6847be5614536ec4c39f886f4f6e58"
     },
+    {
+      "id": "test-integrity",
+      "version": "0.0.1",
+      "managed": false,
+      "sha256": "c140c5ca23c3e9dde10712b889840ee9a4a1976f7cb328d088f8f781e03c274e",
+      "source": "local",
+      "artifacts_sha256": "c5e8de5994b7c5a044203babbca3db334500cab99e66ac409ba07daa5baf51a6"
+    },
     {
       "id": "token-efficiency",
       "version": "0.0.1",
diff --git a/docs/agentic-risk-coverage.md b/docs/agentic-risk-coverage.md
index 8720330..26005e0 100644
--- a/docs/agentic-risk-coverage.md
+++ b/docs/agentic-risk-coverage.md
@@ -42,7 +42,7 @@ Chock's guard degrades to allow, so no row here earns it.
 | …an agent poisoning its own long-term memory? | `memory-discipline` | `advisory` — and deliberately so here: write-path memory enforcement is a different system than a repo-scoped framework, and this page does not claim it |
 | …direct pushes to `main`, `--no-verify`, force-pushes? | `protect-main-branch` gate, `block-no-verify`, `git-safety` | `enforced-at-commit` (gate); the never-bypass-hooks discipline itself: `advisory` backed by the CI gate, which re-runs `chock check` on the PR head regardless of what was skipped locally |
 | …wildcard permission grants in agent config? | `block-wildcard-agent-permissions` gate | `enforced-at-commit` |
-| …an agent deleting tests or assertions to get green? | `agent-discipline` (`assertion_deletion: block`) | `advisory` today — a deterministic test-integrity gate is a named catalog candidate, not yet a roadmap issue, so this row stays `advisory` until it is |
+| …an agent deleting tests or assertions to get green? | `test-integrity` gate, `agent-discipline` (`assertion_deletion: block`) | `enforced-at-commit` (gate) — blocks a deleted test file, a net loss of assertions across the change, or a vacuous assertion (`assert True`, `expect(true)`) added in their place; re-checked in CI on the PR head via the `ci-gate` backstop, so it holds for an inbound contributor whose agent never ran a hook. The pragma `chock: test-removal-reviewed` on the removing line is the reviewed escape hatch. No `pre-tool-use` binding exists, so this is not claimed at the in-agent tier. The ambient rule text remains `advisory` |
 
 ## Against the OWASP Top 10 for Agentic Applications
 
diff --git a/docs/baseline-policies.md b/docs/baseline-policies.md
index 9a105cd..e205ead 100644
--- a/docs/baseline-policies.md
+++ b/docs/baseline-policies.md
@@ -46,6 +46,7 @@ These block risky actions at commit/push time and compile into agent-native cont
 | **`block-invisible-unicode`** | Bidi override/isolate controls and Unicode tag-block characters in staged changes — Trojan Source (CVE-2021-42574) and instructions hidden from reviewers but legible to agents. ZWJ and RTL marks pass by design (emoji, internationalised text). |
 | **`protect-agent-config`** | Shell writes to the agent's own instruction, permission and vendored-enforcement files (`AGENTS.md`, `.claude/settings.json`, `.mcp.json`, `.chock/bin/` …) — self-modification refused before it runs; regenerate through `chock sync` instead. |
 | **`block-wildcard-agent-permissions`** | Committed everything-grants in agent settings and MCP configs — bare-wildcard shell grants and allow-everything tool lists. Scoped grants pass; the twin of the catalog's `block-wildcard-iam`. |
+| **`test-integrity`** | A change that wins green CI by weakening the tests instead of fixing the code: a deleted test file, a net loss of assertions across the change, or a vacuous assertion (`assert True`, `expect(true)`) added in their place. The pragma `chock: test-removal-reviewed` on the removing line is the reviewed escape hatch. |
 
 > These are **best-effort friction, not a security boundary.** Known bypasses (aliases, quoting,
 > non-standard clients) are documented on each policy. Pair them with the CI-gate backstop.
@@ -79,7 +80,7 @@ own the same way: a folder, a manifest, and (optionally) an
 
 ## Cross-platform & tested
 
-`scan-secrets`, `protect-main-branch` and `verify-dependency-exists` are **declarative**
+`scan-secrets`, `protect-main-branch`, `verify-dependency-exists` and `test-integrity` are **declarative**
 (`hook.gate` in `manifest.yaml`); `chock compile` emits the cross-platform git-hook shims and
 a self-contained, stdlib-only Python runner. The remaining guards ship bash implementations invoked
 through the PreToolUse adapter. `.gitattributes` pins scripts to LF so their hashes — and therefore
diff --git a/spec/gate-dsl.md b/spec/gate-dsl.md
index 7e6d95a..7dd8f20 100644
--- a/spec/gate-dsl.md
+++ b/spec/gate-dsl.md
@@ -7,7 +7,7 @@ For `artifact: hook` policies, the gate is declared under `hook.gate` in `manife
 
 | field | required | type | notes |
 |-------|----------|------|-------|
-| `kind` | yes | string | `content_regex`, `forbidden_ref`, `dependency_allowlist`, or `egress_allowlist` (gateway-only) |
+| `kind` | yes | string | `content_regex`, `forbidden_ref`, `dependency_allowlist`, `test_integrity`, or `egress_allowlist` (gateway-only) |
 | `on` | yes | list | events: `commit`, `push`, `tool_use`. The key must be quoted `"on"` in YAML. |
 | `action` | yes | string | `block`, `verify`, or `warn` |
 | `message` | yes | string | printed to stderr when the gate blocks |
@@ -84,6 +84,22 @@ a parse error is never converted into a block.
 
 Extracted names are lowercased and compared against a lowercased allowlist.
 
+### `kind: test_integrity`
+
+| param | required | type | notes |
+|-------|----------|------|-------|
+| `test_path_regex` | yes | string | regex matched against staged paths to identify test files |
+| `assertion_pattern` | yes | string | regex matched against a line to count it as an assertion |
+| `dummy_assertion_pattern` | no | string | regex for a vacuous assertion (`assert True`, `expect(true)`); matched only on added lines |
+| `allowlist_pragma` | no | string | regex matched on a line; a match on an added line skips that file's counting entirely |
+
+Blocks three shapes of a change that wins green CI by weakening the tests rather than
+fixing the code: a deleted test file, a **net** loss of assertions across the whole
+change (removed lines matching `assertion_pattern` outnumber added ones, counted only in
+files matching `test_path_regex`), and a vacuous assertion added in place of a real one.
+Only the staged diff is read (`removed_lines`/`added_lines`), so a file that already
+contained fewer assertions before this commit does not block it.
+
 ## Runtime note
 
 The emitted git-hook shim probes for a working Python 3 interpreter in the order `python3`, `python`, `py` and then calls `.chock/bin/gate.py`. This makes enforcement work on stock Windows as well as POSIX without `pip install`.
diff --git a/src/chock/gate/runner.py b/src/chock/gate/runner.py
index e156131..4c1c45e 100644
--- a/src/chock/gate/runner.py
+++ b/src/chock/gate/runner.py
@@ -80,8 +80,7 @@ def added_lines(self, path: str) -> list[str]:
     def removed_lines(self, path: str) -> list[str]:
         """The deleted side of the diff -- what a test-weakening change takes away."""
         out = self._git("diff", *self._range(), "-U0", "--", path)
-        return [line[1:] for line in out.splitlines()
-                if line.startswith("-") and not line.startswith("---")]
+        return [line[1:] for line in out.splitlines() if line.startswith("-") and not line.startswith("---")]
 
     def staged_blob(self, path: str) -> str:
         """The proposed content: staged in index mode, committed at HEAD in range mode."""
diff --git a/src/chock/validation/schemas/manifest.hook.json b/src/chock/validation/schemas/manifest.hook.json
index 12ada1e..4109440 100644
--- a/src/chock/validation/schemas/manifest.hook.json
+++ b/src/chock/validation/schemas/manifest.hook.json
@@ -25,7 +25,8 @@
           "enum": [
             "content_regex",
             "forbidden_ref",
-            "dependency_allowlist"
+            "dependency_allowlist",
+            "test_integrity"
           ]
         },
         "on": {
diff --git a/tests/test_manifest_validation.py b/tests/test_manifest_validation.py
index c79ac11..8f1126d 100644
--- a/tests/test_manifest_validation.py
+++ b/tests/test_manifest_validation.py
@@ -119,6 +119,59 @@ def test_manifest_gate_params_missing_required(tmp_path: Path) -> None:
     assert "manifest_gate_params" in _codes(report)
 
 
+def test_manifest_gate_params_test_integrity_valid(tmp_path: Path) -> None:
+    """A test_integrity gate with its required params validates cleanly."""
+    data = {
+        **MINIMAL_RULE,
+        "id": "test-hook",
+        "name": "Test Hook",
+        "artifact": "hook",
+        "enforcement": "block",
+        "hook": {
+            "gate": {
+                "kind": "test_integrity",
+                "on": ["commit"],
+                "action": "block",
+                "message": "blocked",
+                "params": {
+                    "test_path_regex": r"(^|/)tests?/",
+                    "assertion_pattern": r"\bassert\b",
+                },
+            }
+        },
+    }
+    policy_dir = _manifest_dir(tmp_path, "test-hook", data)
+    report = Report()
+    manifest, _ = load_manifest(policy_dir)
+    check_manifest_schema(policy_dir, manifest, "hook", report)
+    assert "manifest_gate_params" not in _codes(report)
+
+
+def test_manifest_gate_params_test_integrity_missing_required(tmp_path: Path) -> None:
+    """Rule 4: a test_integrity gate without assertion_pattern is rejected."""
+    data = {
+        **MINIMAL_RULE,
+        "id": "test-hook",
+        "name": "Test Hook",
+        "artifact": "hook",
+        "enforcement": "block",
+        "hook": {
+            "gate": {
+                "kind": "test_integrity",
+                "on": ["commit"],
+                "action": "block",
+                "message": "blocked",
+                "params": {"test_path_regex": r"(^|/)tests?/"},
+            }
+        },
+    }
+    policy_dir = _manifest_dir(tmp_path, "test-hook", data)
+    report = Report()
+    manifest, _ = load_manifest(policy_dir)
+    check_manifest_schema(policy_dir, manifest, "hook", report)
+    assert "manifest_gate_params" in _codes(report)
+
+
 def test_manifest_self_dependency(tmp_path: Path) -> None:
     """Rule 5: a policy must not list itself in dependencies.policies."""
     data = {
diff --git a/tests/test_test_integrity_gate.py b/tests/test_test_integrity_gate.py
index 925f581..fb86045 100644
--- a/tests/test_test_integrity_gate.py
+++ b/tests/test_test_integrity_gate.py
@@ -68,9 +68,15 @@ def test_non_test_paths_are_not_policed(tmp_path: Path) -> None:
     assert _verdict(repo, gate) == 0
 
 
+def test_a_spec_directory_of_prose_is_not_policed(tmp_path: Path) -> None:
+    """A `spec/` directory of design docs (this repo's own layout) is not RSpec test code."""
+    repo, gate = _repo(tmp_path)
+    stage(repo, "spec/gate-dsl.md", "docs describing `assert True` as an example of a vacuous check\n")
+    assert _verdict(repo, gate) == 0
+
+
 def test_a_reviewed_removal_is_allowed_through(tmp_path: Path) -> None:
     """The escape hatch is deliberate, in the diff, and named — not a config toggle."""
     repo, gate = _repo(tmp_path)
-    stage(repo, "tests/test_math.py",
-          "def test_adds():  # chock: test-removal-reviewed\n    assert add(1, 2) == 3\n")
+    stage(repo, "tests/test_math.py", "def test_adds():  # chock: test-removal-reviewed\n    assert add(1, 2) == 3\n")
     assert _verdict(repo, gate) == 0