The IPC Contract Audit

Treat schema changes as end-to-end runtime changes, not local type edits.

Required Chain

When the task changes a provider or IPC payload, inspect this full chain:

• electron/providers/types.ts
• src/lib/providers/provider.types.ts
• src/lib/providers/schemas.ts — Zod discriminated union for NormalizedProviderEvent
• src/types/window-api.d.ts
• electron/preload.ts
• electron/main/ipc/schemas.ts
• producer call sites (providers, host-service, store actions)
• consumer call sites (replay, chat UI, diagnostics)

Do not assume TypeScript is enough. electron/main/ipc/schemas.ts and src/lib/providers/schemas.ts both use strict Zod — they silently reject extra fields and silently drop unknown event variants at parseNormalizedEvent.

Event Sync Checks

When adding, renaming, or reshaping a normalized event:

• update the TypeScript union in src/lib/providers/provider.types.ts
• update the matching Zod object in src/lib/providers/schemas.ts (same commit — TS and Zod diverge silently)
• update provider emitters in electron/providers/
• update replay handlers in src/lib/session/provider-event-replay.ts
• update diagnostics / chat rendering if the event is user-visible

Schema variable names (e.g. StaveExecutionProcessingEventSchema) must mirror the TypeScript literal for easy auditing.

Host-Service Dispatch Pitfall

electron/host-service.ts dispatches IPC requests. Async runtime functions (e.g. attachSession, createSession) must be awaited before passing their result to respond(). A bare respond(fn(...)) when fn returns a Promise becomes JSON.stringify(Promise) === "{}" — the renderer sees an empty object with no error.

Provider CLI Environment Parity

Changes to executable lookup, runtime env, CLI launch env, or tooling status probes must respect the env-builder contract shared across both adapters. Required check files:

• electron/providers/executable-path.ts
• electron/providers/cli-path-env.ts
• electron/providers/claude-sdk-runtime.ts
• electron/providers/codex-app-server-runtime.ts
• electron/providers/runtime.ts
• electron/main/utils/tooling-status.ts

A passing claude auth status or codex --version probe is not sufficient — verify the actual turn-start path too. See the-provider-runtime-symmetry for the full symmetry protocol.

Common Failure Modes

1. New field added in TypeScript only — rejected at runtime by strict Zod in electron/main/ipc/schemas.ts.
2. New normalized event added without matching Zod entry — silently dropped by parseNormalizedEvent.
3. Event renamed on the producer but not on replay or consumer paths.
4. Host-service async result passed to respond() without await.

Symmetry Rule

If the behavior is meant to be provider-agnostic, inspect both Claude and Codex adapters. Invoke the-provider-runtime-symmetry when the change is adapter-local but the behavior should be shared.

Verification

• run bun run typecheck after contract changes
• if provider runtime behavior changed, smoke-check both Claude and Codex paths (start a turn in each)
• if CLI env changed, verify both the probe path and the actual turn-start path

Output

Return:

• the contract group you audited
• files confirmed
• files still at risk
• verification still required