---
id: review-001-schema-internal-visibility
name: Enforce Internal-op invisibility on GET /schema (SRV-02, PRJ-06, GW-02)
status: pending
depends_on: []
scope: narrow
risk: medium
impact: component
level: implementation
tags: [server, gateway, review-001, security]
---

## Description

Review 001 findings SRV-02 + PRJ-06 + GW-02 — three faces of one
visibility gap on the discovery axis:

- **SRV-02** (`src/gateway/routes.rs:120-137`): `schema_handler` runs only
  `access_check_for_op`; it skips the `is_internal_op` pre-check that
  `/call`, `/batch`, `/subscribe`, `/publish` all apply. Internal ops carry
  `AccessControl::default()`, so an unauthenticated caller can fetch the
  full spec (visibility, schemas, `access_control`) of an op it cannot
  call. `POST /call` on the same op correctly 404s (tested); `GET /schema`
  does not — the invisibility invariant (ADR-015 §2) is defeated on the
  discovery axis.
- **PRJ-06** (`src/adapters/to_mcp.rs:148-174`): the MCP `schema` tool has
  the identical gap — no per-op pre-check, full spec including
  `required_scopes` returned for forbidden ops. The test
  `schema_returns_full_operation_spec` enshrines the leak.
- **GW-02**: `/search` and `/schema` are per-identity GETs with no
  `Cache-Control: no-store` / `Vary: Authorization`, so shared caches may
  serve caller A's filtered response to caller B.

Fix all three in one pass since they share the pre-check logic and test
fixtures: add the 404 guard to `schema_handler`; run the same
`access_check_for_op` pre-check in the MCP `schema` tool (or filter the
returned spec per identity) and fix the enshrining test; add cache headers
to the two per-identity GETs.

## Acceptance Criteria

- [ ] `GET /schema?name=<internal>` → 404 unauthenticated, for an unauthorized identity, and for an anonymous identity (test)
- [ ] MCP `schema` tool denies/404s unauthorized ops symmetrically with HTTP `/schema` (test); enshrining test fixed
- [ ] `/search` + `/schema` responses carry `Cache-Control: no-store` (and `Vary: Authorization` where a token can change the body)
- [ ] `cargo test` and `cargo clippy --all-targets -- -D warnings` pass
- [ ] `cargo test --all-features` passes (the MCP half is feature-gated)

## References

- docs/reviews/001-initial-implementation-review.md (SRV-02, PRJ-06, GW-02)
- docs/architecture/decisions/015-privilege-model-and-authority-context.md
- docs/architecture/decisions/041-mcp-tool-gateway-pattern.md

## Notes

> Agent fills during implementation.

## Summary

> Filled on completion.