---
id: adapter-from-openapi
name: from_openapi adapter (parse + forwarding handlers)
status: pending
depends_on: [client-http-host]
scope: broad
risk: medium
impact: component
level: implementation
tags: [adapters, phase-3]
---

## Description

Port `adapters/from_openapi.rs` (~2k lines, the largest port) from
`/workspace/@alkdev/alknet/crates/alknet-http/src/adapters/from_openapi.rs`:
OpenAPISpec (from_json/from_yaml/from_str JSON-first per ADR-051,
from_value), $ref resolution, HttpServiceConfig, per-op
HandlerRegistration construction (Internal by default, FromOpenAPI
leaf provenance), forwarding handlers (path-template substitution,
query params, auth header from capabilities, content-type branching),
SSE→StreamingHandler for Sub ops (HandlerKind::Stream), error fidelity
(`HTTP_<status>` codes). Type paths move to alkcall::client (adapter
contract) and alkcall::registry.

## Acceptance Criteria

- [ ] JSON + YAML + from_str detection ports with tests
- [ ] Handler construction: Query/Mutation→Once, Sub→Stream; Pub never produced (v1)
- [ ] Forwarding: path params, query params, auth injection from Capabilities, error mapping — unit tested (mock HTTP via local axum server)
- [ ] No env-var reads
- [ ] `cargo test` passes

## References

- docs/architecture/http-adapters.md (§from_openapi, §Forwarding handler, §Error Fidelity)
- docs/architecture/decisions/023-operation-error-schemas.md, 051-yaml-input-for-from-openapi.md
- Old source: `/workspace/@alkdev/alknet/crates/alknet-http/src/adapters/from_openapi.rs`

## Notes

> Agent fills during implementation. Largest single port — consider
> splitting internally (parse half / handler half) if review flags it.

## Summary

> Agent fills on completion.