[shivros]

Summary

• Add the reusable hydra-mcp-http stateless MCP Streamable HTTP runtime for protocol 2026-07-28.
• Validate explicit Origin policy, JSON/SSE media negotiation, JSON-RPC metadata, mirrored MCP headers, tool manifests, safe errors, and Base64-sentinel tool names.
• Share the generated-location Notes MCP adapter between stdio and HTTP, with a real loopback server/discover -> tools/list -> tools/call acceptance path.
• Document embedding and intentionally unsupported session, legacy, CORS/PNA, and x-mcp-header boundaries.

Linear: COD-525

Scope boundaries

• No api/operations.yaml, generated operation artifact, business operation, authentication policy, deployment, release, or AnkiMCP change.
• The generic runtime never binds a listener or selects a mount path; the Notes example owns 127.0.0.1:8942 and /mcp.

Verification

• cargo build --locked --all-targets
• cargo test --locked --all-targets (60 codegen, 3 runtime unit, 7 runtime transport, 1 real Notes loopback, 14 Notes surface, and 6 security-scan tests)
• cargo clippy --locked --workspace --all-targets -- -D warnings
• cargo fmt --all -- --check
• cargo run --locked -p hydra-codegen --bin hydra-codegen -- check in examples/notes, examples/security-scan, and examples/ts-client
• Two hydra-codegen write passes in each example were byte-identical to the committed four-artifact snapshots and to each other; final codegen checks passed.
• examples/ts-client: npm ci --ignore-scripts --no-audit --no-fund, generated check, typecheck, build, and nested-schema test
• creed diff
• git diff --check

All gates passed on signed commit 001de6ff52b5cddaa7e855c0909da656aef026d5.

[shivros]

🤖 Automated Review Panel

Reviewer A — GPT-5.6 Terra

Initial result: BLOCK; findings resolved before handoff.

• Correctness: invalid JSON-RPC IDs (object/array/boolean) were initially echoed in error responses. The runtime now normalizes invalid or missing IDs to null and the transport test asserts that behavior.
• Evidence: the initial panel noted that the focused matrix did not explicitly exercise dispatch errors, legacy initialize, or OPTIONS. Added deterministic coverage for the isError tool-result envelope, initialize method-not-found, and OPTIONS 405/no-CORS behavior. The OpenSpec tasks.md evidence is now updated with the executed gate matrix.

Runner follow-up verification after these fixes: cargo build --locked --all-targets, cargo test --locked --all-targets, strict Clippy, fmt, codegen freshness/determinism, TypeScript checks, creed diff, and git diff --check all pass.

Reviewer B — Gemini 3 Flash Preview

Review findings and disposition:

• Base64 sentinel/control handling: the reviewer questioned rejecting decoded control characters. This is intentional: the frozen contract requires malformed/control values to be rejected before comparison, and construction rejects tool names containing control characters. Base64 remains supported for valid non-ASCII, whitespace, and other unsafe plain-header values; a Unicode sentinel round-trip is covered by tests.
• Structured content: the reviewer questioned the JSON text mirror. The frozen design explicitly requires a successful dispatch Value in both structuredContent and backwards-compatible JSON text content; the transport test asserts both.
• OpenSpec evidence: the reviewer identified the missing living task evidence during the initial pass. openspec/changes/add-mcp-streamable-http/tasks.md now records all verified tasks and exact gate evidence.
• The remaining Origin and x-mcp-header observations match the intentionally strict frozen contract and are documented/tested.

Panel conclusion

The review findings were addressed or explicitly resolved against the frozen contract. No unresolved correctness blocker remains in the final commit.

[shivros]

Auto-Merge Gate

Confidence: 0.86

Rationale: Implements COD-525's stateless MCP Streamable HTTP transport as a contained runtime crate, wires the Notes reference through the shared dispatcher, documents the explicit protocol/security boundaries, and includes focused transport plus real loopback acceptance coverage. The existing dual-model review panel records that its initial correctness findings were fixed before handoff; no unresolved review activity remains.

Checks observed: CI Test and Creed context drift completed successfully on 001de6ff52b5cddaa7e855c0909da656aef026d5.

Scope limits checked: no deployment, release, authentication-policy, billing, data-deletion, or credential changes; COD-525 has no manual-review marker.