---
phase: 01.1-hexagonal-architecture
plan: 02
subsystem: api
tags: [trpc, zod, rpc, type-safety]

# Dependency graph
requires:
  - phase: 01.1-01
    provides: EventBus interface type
provides:
  - tRPC router with health/status procedures
  - AppRouter type for client type-safety
  - Zod schemas for runtime validation
affects: [01.1-06-cli-trpc-integration, future-webui]

# Tech tracking
tech-stack:
  added: [@trpc/server, @trpc/client, zod]
  patterns: [tRPC caller factory for testing, Zod output validation]

key-files:
  created: [src/trpc/router.test.ts]
  modified: [src/trpc/router.ts, src/trpc/index.ts]

key-decisions:
  - "Use Zod for output validation to ensure runtime type safety"
  - "Procedures return same shape as existing HTTP endpoints for consistency"

patterns-established:
  - "tRPC procedures use ctx for dependency injection"
  - "createCallerFactory pattern for unit testing procedures"

# Metrics
duration: 6min
completed: 2026-01-30
---

# Phase 01.1 Plan 02: tRPC Foundation Summary

**Type-safe tRPC router with health and status procedures, Zod validation, and comprehensive tests**

## Performance

- **Duration:** 6 min
- **Started:** 2026-01-30T12:52:38Z
- **Completed:** 2026-01-30T12:58:19Z
- **Tasks:** 2
- **Files modified:** 3

## Accomplishments

- Added health procedure returning { status, uptime, processCount }
- Added status procedure returning { server: {startedAt, uptime, pid}, processes: [] }
- Zod schemas for runtime output validation
- AppRouter type exported for client type-safety
- 16 tests covering procedures and schema validation

## Task Commits

Each task was committed atomically:

1. **Task 1: Install tRPC dependencies and create router foundation** - `437e76e` (done in prior session as part of Plan 01.1-01)
2. **Task 2: Define procedures matching HTTP endpoints with tests** - `551e516` (feat)

**Plan metadata:** (this commit)

_Note: Task 1 was completed as part of Plan 01.1-01 execution. This plan focused on Task 2._

## Files Created/Modified

- `src/trpc/router.ts` - Added appRouter with health/status procedures, Zod schemas
- `src/trpc/index.ts` - Export AppRouter type and schemas
- `src/trpc/router.test.ts` - 16 tests for procedures and validation

## Decisions Made

1. **Zod for output validation** - Ensures runtime type safety; procedures validate their outputs match declared schemas
2. **Match HTTP endpoint shapes** - health and status procedures return same data as existing `/health` and `/status` HTTP endpoints for consistency

## Deviations from Plan

### Auto-handled

**1. [Rule 3 - Blocking] Task 1 already completed**
- **Found during:** Task 1 verification
- **Issue:** tRPC foundation files already existed from Plan 01.1-01 execution
- **Resolution:** Verified existing files met Task 1 requirements, proceeded to Task 2
- **Impact:** None - reduced work, no code changes needed for Task 1

## Issues Encountered

None - plan executed as expected.

## User Setup Required

None - no external service configuration required.

## Next Phase Readiness

- tRPC router ready for HTTP adapter integration (Plan 01.1-06)
- Type-safe contract established for CLI-server communication
- Procedures match existing HTTP endpoint contracts

---
*Phase: 01.1-hexagonal-architecture*
*Completed: 2026-01-30*
