# Refactor Changelog — Input/Output Unification + Presenter + Error Middleware + Public-Surface Cleanup **Started:** 2026-05-06 **Spec:** [2026-05-06-input-output-unification-design.md](../specs/2026-05-06-input-output-unification-design.md) **Plan:** [2026-05-06-plan-9-io-unification.md](../plans/2026-05-06-plan-9-io-unification.md) **Branch:** feature/io-unification This document captures every architectural change made during Plan 9 execution, organized by category. After the plan is merged, use the "Doc update checklist" at the bottom to update external docs in a single follow-up pass — combined with the still-pending Plan 8 doc-update items so docs are written once for the post-Plan-9 state. --- ## 1. Files added - packages/core-shared/src/trpc/define-error-middleware.ts — middleware factory mapping [ErrorCtor, TRPC_CODE] tuples to TRPCError translation - packages/core-shared/src/trpc/define-error-middleware.test.ts — 4 tests covering mapped translation, multiple codes, unmapped passthrough (verifies INTERNAL_SERVER_ERROR + cause preservation), cause preservation - packages/auth/src/integrations/api/procedures.ts — authProcedure with feature error map (InputParse → BAD_REQUEST, Auth/Unauthenticated → UNAUTHORIZED, Unauthorized → FORBIDDEN) - packages/auth/src/ui/index.ts — placeholder UI surface (no queries today; mutations only) ## 2. Files modified - packages/core-shared/src/trpc/init.ts — `t` instance now exported (was internal const) so feature procedures.ts can do `t.procedure.use(...)` - packages/core-shared/package.json — added "./trpc/define-error-middleware" subpath export - packages/core-shared/tsconfig.json — set `rootDir: "."` and added `@/*` path alias so test files using `@/` resolve correctly under `tsc --noEmit` - packages/auth/src/application/use-cases/sign-in.use-case.ts — input + output schemas; output.parse before return; SignInInput/SignInOutput types exported - packages/auth/src/application/use-cases/sign-up.use-case.ts — input + output schemas (with confirmPassword refine); output.parse; types exported; removed user from output (presenter extracts cookie) - packages/auth/src/application/use-cases/sign-out.use-case.ts — input schema only (void output, no presenter); SignOutInput exported; takes { sessionId } object instead of raw string - packages/auth/src/interface-adapters/controllers/sign-in.controller.ts — presenter returning cookie; unknown input; ReturnType return type - packages/auth/src/interface-adapters/controllers/sign-up.controller.ts — presenter returning cookie; unknown input - packages/auth/src/interface-adapters/controllers/sign-out.controller.ts — no presenter (void); unknown input; Promise return - packages/auth/src/integrations/api/router.ts — uses authProcedure, .input(xInputSchema) - packages/auth/src/index.ts — schemas + types now exported from feature root - packages/auth/package.json — added ./ui subpath - packages/auth/tests/sign-in-flow.feature.test.ts — updated to match new presenter shapes (cookie return, void sign-out, object input) - All affected auth use-case + controller tests updated for new contracts ## 3. Pattern changes (code-level) ### 3.1 Use-case files — input + output schemas + runtime parse auth migrated: all 3 use cases. signIn and signUp export xInputSchema + xOutputSchema + types; signOut exports xInputSchema only (void output). All non-void use cases end with `xOutputSchema.parse(result)` before returning. ### 3.2 Controller files — presenter + unknown input + view return type auth migrated: all 3 controllers. signIn/signUp have `function presenter(value: XOutput)` returning `value.cookie`; return type is `ReturnType`. signOut has no presenter (void). All controllers accept `unknown` input and safeparse with the use-case schema. ### 3.3 tRPC integration — feature-scoped procedures, schema reuse from use cases auth migrated: authProcedure in procedures.ts wraps defineErrorMiddleware with 4-tuple error map. Router uses `authProcedure.input(xInputSchema)` for all 3 procedures — no more local schema redefinition. ## 4. Error-middleware adoption - core-shared infrastructure landed; feature routers will adopt in Tasks 3-7. - Discriminator: `instanceof Ctor` (not error name string), so duck-typing is impossible — features pass their own class constructors. - Cause preservation: TRPCError carries the original domain error in `.cause` for client structured-error inspection. - Note on tRPC v11 behavior: unmapped errors still surface as `TRPCError(code: INTERNAL_SERVER_ERROR)` because tRPC's `createCaller` wraps all procedure errors. Our middleware does not interfere — the original error is preserved as `.cause` for inspection. ## 5. Public-API surface ### 5.1 ./ui subpath added per feature auth: `./ui` subpath added to package.json exports; `src/ui/index.ts` placeholder created (auth has no query builders — all procedures are mutations). ### 5.2 Feature root index.ts cleanup auth: root `src/index.ts` now exports all use-case schemas (signInInputSchema, signInOutputSchema, signUpInputSchema, signUpOutputSchema, signOutInputSchema) and types (SignInInput/Output, SignUpInput/Output, SignOutInput, ISignInUseCase, ISignUpUseCase, ISignOutUseCase) plus controller type aliases. ## 6. Test additions ### 6.1 R25 — output-validation tests (use case) auth: signIn and signUp each have 2 new R25 tests — one verifying that a malformed service response throws (Zod parse error), one verifying the output schema parses a valid shape. signOut is void — no R25 test. ### 6.2 R26 — router error-mapping tests auth: 2 new R26 tests in router.test.ts — UNAUTHORIZED on missing user (AuthenticationError translation), BAD_REQUEST on Zod schema failure (schema validation at procedure boundary). ### 6.3 R27/R28 — presenter shape tests (populated when controllers with non-identity presenters add view-shape assertions) ## 7. Open issues / deferred decisions (populated as encountered) --- ## Doc update checklist (deferred — combined with paused Plan 8 doc pass) After Plan 9 lands, the still-pending Plan 8 doc-update items resume and now also pick up Plan 9 rules. Each item below covers BOTH plans' material so we touch every file once. - [ ] `CLAUDE.md` — Key Conventions: append schema-in-use-case rule, presenter rule, controller `unknown` input rule, `./ui` subpath rule, schema-export-from-root rule - [ ] `AGENTS.md` (root) — Per-Package Conventions: document `./ui` subpath, schema reachability from feature root, factory-bound use cases / controllers (carry-over from Plan 8) - [ ] `docs/guides/adding-a-feature.md` — restructure to use the Plan-9 use-case template (with input + output schemas + parse), the Plan-9 controller template (with presenter), and the new `procedures.ts` step (per-feature error map) - [ ] `docs/guides/tdd-workflow.md` — update mock decision tree + worked example to factory injection (Plan 8) + R25 output-validation test pattern (Plan 9) + R26 router-error-mapping test pattern (Plan 9) - [ ] `docs/guides/testing-strategy.md` — Mocking section: direct factory injection (Plan 8); R25/R26/R27/R28 test obligations (Plan 9) - [ ] `docs/architecture/vertical-feature-spec.md` — §6 file shape: schemas + presenter + procedures.ts; §10 testing: R25/R26/R27/R28 - [ ] `docs/architecture/overview.md` — data-flow box: add input schema, output schema, presenter, error-middleware lanes - [ ] `docs/architecture/dependency-flow.md` — verify (no expected change beyond a `./ui` mention) - [ ] `docs/decisions/adr-012-lazar-conformance.md` — append note that input/output unification + presenter + error middleware land in ADR-013 - [ ] `docs/decisions/adr-013-input-output-unification.md` — created in this plan's final task (Task 9); link from prior ADRs - [ ] Per-feature `AGENTS.md` (auth/blog/media/marketing-pages/navigation) — Plan 8 file paths + Plan 9 schema/presenter/procedures patterns - [ ] `packages/core-testing/AGENTS.md` — note R25/R26 test patterns - [ ] `packages/core-shared/AGENTS.md` — document `defineErrorMiddleware` and the `t` re-export - [ ] Plan 8 plan/spec — add a one-line annotation that some controller/router patterns shifted in Plan 9; link to this changelog --- ## Notes for the doc-update pass author When updating external docs, apply these substitutions globally: | Old reference | New reference | |---|---| | Use case takes `{ x }` directly typed | Use case takes `XInput` (`z.infer`); schema lives in same file | | Use case returns `Promise` | Use case returns `Promise` validated by `xOutputSchema.parse(...)` | | Controller imports `z` and defines local `inputSchema` | Controller imports `xInputSchema` from the use-case file | | Controller input typed `Partial>` | Controller input typed `unknown` | | Controller returns `Promise` | Controller has `function presenter(value: XOutput)`; returns `Promise>` (or `Promise` for void use cases) | | Router uses `publicProcedure` from `core-shared/trpc/init` | Router uses feature's `xProcedure` from `./procedures` | | Router redefines input schema as `z.object({...})` in `.input(...)` | Router uses `.input(xInputSchema)` imported from the use-case file | | Domain error reaches the wire as a generic `TRPCError({ code: "INTERNAL_SERVER_ERROR" })` | Domain error mapped to specific code by `defineErrorMiddleware` in `procedures.ts` | | Frontend imports `articleBySlugQuery` from `@repo/blog` | Frontend imports from `@repo/blog/ui` |