fix(session): validate broker runtime boundaries

[benvinegar]

Summary

• add one fixed-contract parser registry for registration, snapshots, exact command input/result pairs, and daemon/producer envelopes
• validate external JSON as unknown before bridge dispatch or state mutation, with stable redacted protocol errors
• parse app payloads exactly once and derive daemon parsing from the controller-owned registry
• strictly validate Hunk command payloads, responses, health, capabilities, and legacy registration limits
• add malformed corpora, parser-throw, atomicity, compatibility, and client-response coverage

Validation

• full tests: 1,778 passed, 8 skipped
• PTY integration: 135 passed, 1 skipped
• focused broker/Hunk tests: 169 passed
• bun run lint
• bun run typecheck
• bun run deps:check
• git diff --check

Stack

• Depends on feat(session): add signed broker authorization #901 and fix(session): bind broker state to peer ownership #898
• Next: bounded scheduling/backpressure and runtime parity
• Final: Hunk automatic credential integration

This PR description was generated by Pi using gpt-5.6-sol

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1 Skipped Deployment

Project	Deployment	Actions	Updated (UTC)
hunk-web	Ignored	Preview	Aug 30, 2026 1:06am

[greptile-apps]

Greptile Summary

The PR centralizes strict runtime parsing for broker registration, snapshots, commands, daemon envelopes, capabilities, health data, and Hunk client responses. It also adds malformed-input, parser-failure, atomicity, and compatibility coverage.

• Introduces a controller-owned parser registry shared by daemon and producer boundaries.
• Validates command inputs and results before dispatch, state mutation, or request resolution.
• Adds strict Hunk schemas for reload inputs, responses, capabilities, registrations, and snapshots.
• Preserves redacted protocol failures across authenticated HTTP and WebSocket boundaries.

Confidence Score: 4/5

The PR should not merge until accepted dispatch deadlines and idempotency keys are either enforced end-to-end or rejected instead of being silently ignored.

The new public parser accepts execution-control fields, but the daemon omits them when dispatching, so callers can observe commands executing despite expired deadlines or duplicate idempotency keys.

Files Needing Attention: packages/session-broker/src/protocolParsers.ts, packages/session-broker/src/daemon.ts

Important Files Changed

Filename	Overview
packages/session-broker-core/src/validation.ts	Adds bounded primitives and stable redacted protocol errors for cross-process input validation.
packages/session-broker-core/src/brokerState.ts	Validates command inputs/results and preserves existing session state when replacement parsing fails.
packages/session-broker/src/protocolParsers.ts	Centralizes exact broker envelope parsing, but accepts deadline and idempotency controls that daemon dispatch ignores.
packages/session-broker/src/daemon.ts	Routes validated HTTP and WebSocket envelopes through the parser registry while dropping two newly accepted dispatch controls.
packages/session-broker/src/connection.ts	Parses daemon commands before bridge dispatch and validates application results before returning them.
src/session/broker/protocolParsers.ts	Defines the fixed Hunk command parser registry and strict command-specific input/result contracts.
src/session/protocolSchemas.ts	Adds strict request, response, capability, and reload-input schemas aligned with current Hunk protocol types.
src/session/agent/cliClient.ts	Validates successful daemon responses instead of trusting asserted response types.

Sequence Diagram

sequenceDiagram
    participant Caller
    participant Daemon
    participant Registry as Protocol parser registry
    participant Broker
    participant App
    Caller->>Daemon: Authenticated JSON dispatch
    Daemon->>Registry: Parse structural request
    Registry-->>Daemon: Selector, command, input, controls
    Daemon->>Broker: Dispatch parsed command
    Broker->>Registry: Parse command input
    Broker->>App: Validated WebSocket command
    App->>Registry: Parse command result
    App-->>Broker: Validated result
    Broker-->>Daemon: Resolve pending request
    Daemon-->>Caller: Authenticated response

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Prompt To Fix All With AI

### Issue 1
packages/session-broker/src/protocolParsers.ts:325-330
**Dispatch controls are discarded**

When an authenticated caller supplies an expired `deadline` or an `idempotencyKey`, this parser accepts both fields but the daemon omits them from `dispatchCommand`, causing expired requests to execute and duplicate requests to run independently without indicating that their controls were ignored.

---

For each issue above, determine whether it is valid and should be fixed. If so, fix it directly.

_{Reviews (1): Last reviewed commit: "fix(session): validate broker runtime bo..." | Re-trigger Greptile}