---
issue: 57
issue_title: "Replace SessionApprovalCache with session Ruleset"
---

# Retro: #57 — Replace SessionApprovalCache with session Ruleset

## Final Retrospective (2026-05-03T21:10:00-04:00)

### Session summary

Replaced `SessionApprovalCache` (directory-prefix matching via `isPathWithinDirectory()`) with `SessionRules` (a plain `Ruleset` evaluated via `evaluate()` / `wildcardMatch()`).
Five commits landed matching the five TDD steps in the plan, plus the docs commit.
Released as v3.10.0 with no user-visible behavior change.
This unblocks #51 (generalize session approvals to all permission surfaces).

### Observations

#### What went well

- The plan-to-implementation mapping was 1:1 — every TDD step produced exactly one commit with the suggested message.
- The wildcard semantics concern (sibling directory false positive) was validated immediately by the `session-rules.test.ts` integration tests.
  `wildcardMatch("/other/project/*", "/other/project-b/foo.ts")` correctly returns false because the regex is anchored.
- The `evaluate()` integration approach (checking `sessionRuleset.includes(sessionMatch)` to distinguish a real match from a synthetic default) was clean and required no special-casing.

#### What caused friction (agent side)

1. `missing-context` — The plan identified `tests/handlers/lifecycle.test.ts` and `tests/handlers/tool-call.test.ts` as the test files needing mock updates, but missed `tests/handlers/before-agent-start.test.ts` and `tests/handlers/input.test.ts`, which also construct `makeRuntime()` helpers with `sessionApprovalCache`.
   Vitest (esbuild) does not typecheck, so the stale mocks compiled and ran without error.
   The mismatch was only caught by `npm run build` (`tsc`) during the final verification step.
   Impact: required amending the "remove SessionApprovalCache" commit to include two additional test file updates.
   Self-identified during the `tsc` step.

#### What caused friction (user side)

- No friction observed — the session required no user intervention beyond the standard autoformat hooks.
