---
id: review-001-publish-schema-validation-robust
name: Fix /publish schema validation fail-open + per-request recompilation (post-remediation)
status: pending
depends_on: []
scope: narrow
risk: high
impact: component
level: implementation
tags: [gateway, review-001, follow-up]
---

## Description

Follow-up to review-001-gateway-publish-semantics (GW-01): the landed
fix compiles the op's `publish_schema` **on every `/publish` request**
(`src/gateway/routes.rs:254-268`) and, when compilation fails, logs a
warning and proceeds with **no validation** — chunks flow to the handler
unvalidated. Two remediation-introduced problems:

- **Fail-open on compile failure** — this reintroduces, conditionally,
  the exact transport-dependent invariant GW-01 closed: a handler that
  registered a `publish_schema` (or a remote import whose schema is
  un-compilable by jsonschema 0.46's dialect) silently receives
  arbitrary JSON over the HTTP path that the wire path would have
  aborted. A registry with one broken schema becomes an unvalidated
  ingest path with only a `tracing::warn` as the tell.
- **Per-request compile cost** — `jsonschema::options().build()` on the
  hot path is CPU + allocation per publish call; a hostile or merely
  busy caller multiplies it.

Fix direction (implementer's choice on mechanism): compile **once per
registration** — cache the compiled `Validator` (or the compile error)
against the op in the gateway state, invalidated on re-registration —
and make compile failure **loud and closed**: the request path surfaces
a server-fault (500, `INTERNAL`-class with the compile error logged at
error level), never a silent skip. Consider whether adapters can reject
un-compilable `publish_schema` values at import/registration time so
the failure lands before any traffic (adapter-side validation where the
schema originates), with the gateway cache as defense in depth.

## Acceptance Criteria

- [ ] Compiled validator (or error) cached per registration; no per-request recompile (test: compile count / perf shape not asserted, but code path is registration-keyed)
- [ ] Un-compilable `publish_schema` → request fails loudly (500/INTERNAL, error logged), chunks never flow unvalidated (test)
- [ ] Schema re-registration (hot reload) picks up the new schema (test)
- [ ] A `publish_schema`-registered Pub op still rejects an invalid chunk (existing GW-01 gate stays green)
- [ ] `cargo test` and `cargo clippy --all-targets -- -D warnings` pass

## References

- docs/reviews/001-initial-implementation-review.md (Part C, GW-01)
- tasks/gateway/review-001-gateway-publish-semantics.md (the landed fix + rationale)
- src/gateway/routes.rs:254-268 (the fail-open)

## Notes

> Agent fills during implementation. Found in the post-remediation
> sweep — not a Review 001 finding itself. Fail-open is the priority
> half; caching is the efficiency half. Registration-side (adapter)
> rejection at import is the preferred end state if alkcall's
> registration surface allows observing `publish_schema` at
> HandlerRegistration time.

## Summary

> Filled on completion.