docs: say where tests and fixtures live and which rules hold it

AGENTS.md

@@ -91,6 +91,13 @@ under `contracts/fixtures/`.
 - Tests mirror source topology one-to-one. Split a source module and its test together; do not add to
   the legacy `interaction.test.ts` or platform `index.test.ts` aggregations. Pure moves carry their
   tests unchanged; rename-only hunks owe no new coverage.
+- A test sits beside the module it is named for: `<module>.test.ts` or `<module>-<aspect>.test.ts`
+  (R84). Cross-module package tests are `index-<aspect>.test.ts` beside `index.ts`; repo-level guards on
+  Swift sources, manifests, docs or scripts live in `test/repo-guards/`.
+- Add no package `exports` entry that points at test support; R83 only lets the legacy count fall. A
+  fixture one package uses stays inside it, imported relatively; helpers shared across packages live only in `@agent-device/test-kit`, a
+  `devDependency` production source never imports and that never depends on `platform-*`,
+  `provider-*`, the daemon or root.
 
 ## Toolchain and worktree traps
 

docs/agents/test-audit.md

@@ -24,7 +24,7 @@ Authoring rejects; audits hunt:
 - type pins posing as runtime assertions (`Equal<A,B> = true`, `X ? true : never`, `satisfies` after erasure, `toHaveLength(n)` over literals); if erasing leaves nothing executable, use `void [fixtures]`;
 - mocks asserting their own inputs; negative controls passing for the wrong reason;
 - names promising more than the input exercises;
-- dead code called only by tests; tests preserving test-only exports.
+- dead code called only by tests; tests preserving test-only exports; a production package `exports` entry only tests import.
 
 ## Retention criteria
 

docs/agents/testing.md

@@ -32,9 +32,8 @@ Two selection traps recur:
 - A workspace package manifest or TypeScript config can rewire all consumers, so the affected
   selector fails open to the full gate set on purpose.
 
-Docs-only changes with no runtime behavior impact need no runtime tests or new tests asserting prose.
-Keep required gates; after those and focused checks pass, repeat or broaden only for changes,
-failures, or unresolved risks.
+Docs-only changes need no runtime tests or tests asserting prose. After the required gates, repeat
+or broaden only for changes, failures, or unresolved risks.
 
 ## Platform and live-device policy
 
@@ -67,13 +66,15 @@ Read the entry file before running a lane. Do not copy its environment matrix he
 
 ## Shared test utilities
 
-Before creating fixtures, look in `@agent-device/test-kit/` (generic) and
-`packages/daemon/src/__tests__/support/` (daemon-shaped). Import named builders from their
-defining module, never through a barrel. Shared `DeviceInfo`, session, snapshot, store,
-runtime-fact, and mocked-binary values belong in a sibling fixture module, not in repeated
-test literals. `PROPERTY_RUNS` and the touch-point/rect arbitraries live in
-`@agent-device/selectors/snapshot-geometry-fixtures`;
-`makeSnapshotState` lives in `@agent-device/capture-kit/snapshot-state-fixtures`.
+Before creating fixtures, look in `@agent-device/test-kit` and
+`packages/daemon/src/__tests__/support/`. Shared `DeviceInfo`, session, snapshot, store,
+runtime-fact, and mocked-binary values belong in a sibling fixture module, not in repeated test
+literals; a fixture one package uses is a `*.fixtures.ts` beside its module. The packages test-kit
+builds on (kernel, contracts, capture-kit, host-kit, command-registry, daemon-contracts) cannot
+declare it; their tests keep helpers local. Never import test-kit in the `vi.mock` factory of a
+module its entry loads (`host-kit/process`, `command`, `file`): spy it in place, as
+`pinOwnProcessStartTime` does. Fixtures a package still exports (R83's legacy count) stay
+importable until moved.
 
 Use `mkdtempForTest` or `mkdtempForTestSync`. Global setup redirects `TMPDIR` for the run and
 removes it after every worker exits — skip per-test cleanup. An interrupted run may leave a
@@ -109,8 +110,8 @@ For structured classifiers, pair the positive case with the closest negative. Wh
 can be identical with and without a typed reason, the negative test must prove the message alone
 cannot activate retry, fallback, or recovery.
 
-Test through public interfaces where practical; never add production exports or test-only
-dependency injection — a missing seam needs a real product seam.
+Test through public interfaces; never add production exports or test-only dependency injection — a
+missing seam needs a real product seam.
 
 ## Properties, fuzzing, and mutation
 
@@ -119,9 +120,7 @@ another example. Keep examples for a real past bug or a named decision. Reuse `P
 budgets so property files stay inside the unit slow-test gate.
 
 Parser fuzz targets live in `scripts/fuzz/targets.ts`. Validation generators carry the invalid
-outcome they planted, so silent acceptance and wrong error codes are failures. Cases run in a
-worker process, so a case that never returns or kills its process is reported as `hang` or `crash`
-against the exact input. Promote a discovered case with the command the harness prints — never
+outcome they planted, so silent acceptance and wrong error codes are failures. Promote a discovered case with the command the harness prints — never
 hand-copy an unshrunk input.
 
 Mutation scope: `scripts/mutation/modules.ts#KERNEL_MODULES` (weekly), `scripts/mutation/run.ts#LANE_SOURCES`