Re-scope tests:meaningfulness-review to assertion-quality only (coverage is now deterministic)

docs/quality/audit.md

@@ -393,7 +393,7 @@ CodeyBox ships these audit-type presets as YAML resources (see `docs/quality/pre
 | `quality`      | LLM review focus for dead code, magic numbers, naming, error handling.       |
 | `completeness` | LLM review focus for TODOs, missing tests, half-finished impls.              |
 | `cheating`     | Deterministic diff-patterns + LLM review focus for agent shortcuts. |
-| `tests`        | Deterministic diff-patterns for no-op assertions + LLM review focus for test meaningfulness. |
+| `tests`        | Deterministic diff-patterns for no-op assertions + LLM review focus for test assertion quality (anti-gaming). Test existence/completeness is owned by the deterministic `tests:coverage` gate below. |
 
 A project enables a preset by listing its name in
 `Audit.AuditTypes` (see `docs/concepts/projects.md`).
@@ -467,6 +467,23 @@ tool auditor (`Required = None`), auto-included by the composer like
 diff. A project opts out via `ExcludedAuditors`. See
 [`coverage.md`](coverage.md) for the full configuration.
 
+### Meaningfulness review vs coverage gate
+
+Test existence and test quality are owned by different auditors by design, so the
+audit converges instead of re-litigating the same gap on every iteration:
+
+* `tests:coverage` (deterministic) owns **existence / completeness**: every executable
+  line changed in the item's diff must be exercised by a test. It is stateless per
+  iteration and never judges whether an assertion is any good.
+* `tests:meaningfulness-review` (LLM) owns **assertion quality / anti-gaming only**,
+  bounded strictly to tests added or modified in the diff: tests that execute code but
+  assert nothing, tests that assert on a mock/stub instead of the result under test,
+  missing error/edge-path assertions inside those tests, and coverage-padding tests
+  written only to satisfy the gate. It must never enumerate untested internal methods,
+  demand tests for code outside the diff, or report the mere absence of a test — that
+  is the coverage gate's job. Like the gate, it is stateless / isolated per audit
+  iteration, with no cross-iteration memory.
+
 ## Rework prompt
 
 When an audit iteration fails, `ReworkPromptBuilder` assembles a prompt

src/CodeyBox.Audit.Llm/LlmReviewAuditor.cs

@@ -115,9 +115,14 @@ public string? SelfReviewGuidance
 """;
 
     private const string TestsGuidance = """
-- **Adequacy**: Ensure each new public class, function, endpoint, and error path has at least one test.
-- **Meaningfulness**: Avoid implementation-mirroring, pure-mock tests, no-assertion tests, and trivially-true assertions.
-- **Edge cases & failures**: Cover boundaries, empty, null, unicode, timeouts, network errors, and resource exhaustion.
+- **Assertion quality, not existence**: test existence and line coverage belong to the
+  deterministic tests:coverage gate — never ask for a test that does not exist and never
+  enumerate untested methods or branches.
+- **Gaming tests**: flag added/modified tests that execute code but assert nothing, assert
+  on a mock/stub instead of the SUT-produced value, or pad coverage without verifying
+  behavior.
+- **Edge assertions within the test**: the added test should assert the error/edge paths
+  it executes, not just the happy path.
 - **Heuristic**: Ask yourself: "if I introduced a plausible bug (off-by-one, inverted condition, forgotten null check), would this test catch it?"
 """;