# Review R003 — Code Review for Step 1

Verdict: **REVISE**

## Findings

1. **Success envelope allows a top-level `error: null` field**  
   `internal/mcp/protocol_test.go:176`

   The Step 1 requirements (and R001) call for asserting that no top-level `error` is present on successful initialize/ping responses. JSON-RPC 2.0 success responses should contain `result` and not `error`; the current assertion only fails when `error` is present and non-null, so a response like `{"jsonrpc":"2.0","id":2,"result":{},"error":null}` would pass this smoke test even though it is not the strict success envelope this task is meant to guard. Please fail whenever the `error` member exists on the success path.

## Verification

- Ran: `go test ./internal/mcp -run 'Streamable|JSONRPC|Codex|Protocol|Ping|Initialize'` — passed (cached).
