---
id: review-001-ref-cycle-guard
name: Bounded, cycle-safe $ref resolution (OAI-01, OAI-08)
status: pending
depends_on: []
scope: narrow
risk: high
impact: component
level: implementation
tags: [adapters, review-001, from-openapi]
---

## Description

Review 001 finding OAI-01 — the single highest-severity finding in the
review (borderline critical, empirically verified):
`resolve_refs_recursive` (`src/adapters/openapi_spec.rs:199-221`) recurses
with no cycle detection and no depth budget. A self-referential component
(`{"$ref":"#/components/schemas/Node"}` inside Node — trees, linked
lists, cursor pagination: common and *valid* OpenAPI) recurses until the
stack is exhausted: `thread has overflowed its stack; fatal runtime
error` → **process abort**. Not a catchable panic; `import()` kills the
whole process — startup crash-loop, or remote DoS if specs are ever
runtime-refreshed/peer-supplied.

Fix: depth budget + visited set keyed on the JSON-pointer path, returning
a clean `CallError`/import error on cycles and over-deep specs. **Do not**
try to preserve full recursive expansion of recursive schemas — the goal
is a clean, loud error (or a depth-limited expansion where the adapter can
safely represent it), not unbounded expansion.

Ride-along: **OAI-08** — guarded `expect`s in `openapi_spec.rs:144,170`
(the "no `expect` outside tests" convention; `if let` costs nothing).

## Acceptance Criteria

- [ ] Import of a self-referential spec returns an error — the process does not abort (the review's named acceptance gate: a test importing a self-referential spec would have caught the abort immediately)
- [ ] Deeply-nested non-circular spec beyond the budget errors cleanly at import (test)
- [ ] A non-recursive spec with `$ref` sharing (refs to a common schema) still imports identically — no false cycle positives (existing suite green)
- [ ] OAI-08 `expect`s replaced
- [ ] `cargo test` and `cargo clippy --all-targets -- -D warnings` pass

## References

- docs/reviews/001-initial-implementation-review.md (Part E, OAI-01, OAI-08)

## Notes

> Agent fills during implementation. Do before anything
> deployment-facing. Deliberately split from the parameter/requestBody
> work (review-001-openapi-import-integrity) so the delicate
> cycle-detection change lands alone.

## Summary

> Filled on completion.