docs(arch): call-completion — ADR-028 peer-scoped filtering + client-and-adapters spec + tasks

Resolves the four gap-analysis decisions (DC-1..4) blocking the alknet-call
client/adapter surface specced in ADR-017:

- ADR-028 (new): locks the one-way door for DC-1 — CallClient registry is
  default-deny (remote_safe: bool on HandlerRegistration, default false across
  all provenance); share-global is an explicit trusted-peer opt-in; filtering
  is a dispatch-time read over the single Layer-0 registry, not a copy.
- client-and-adapters.md (new spec): operationally fills the gap ADR-017 left
  to implementation — CallClient, from_call, from_jsonschema, OperationAdapter
  trait, adapter location map, no-env-vars invariant, exchange-of-operations
  pattern. Keeps call-protocol.md and operation-registry.md under the
  700-line split threshold.
- ADR-017 amended: records DC-2/3/4 v1 defaults (auto-on-reconnect,
  error-on-collision, Result error type) and points DC-1 at ADR-028.
- OQ-25..28 (new): two-way-door remainders (remote_safe shape, AdapterError
  variants, re-import trigger, namespace collision) with v1 defaults recorded.
- Index/cross-ref updates across READMEs and the two existing call specs.

Tasks: 6 task files under tasks/call/ decomposing the completion work along
the gap-analysis priority order — remote-safe-marking (one-way door, first)
→ call-client (phase-risk) → from-call → operation-adapter-trait →
from-jsonschema (parallel with call-client) → review-completion. Graph
validated with taskgraph; parallelism designed in (from-jsonschema runs
concurrent with call-client/from-call once the trait lands).
This commit is contained in:
2026-06-26 12:25:13 +00:00
parent 6940d9858d
commit 2649e068e5
14 changed files with 1817 additions and 11 deletions

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---
id: call/review-completion
name: Review alknet-call client/adapter completion for spec conformance (ADR-017, ADR-028) and no-env-vars invariant
status: pending
depends_on: [call/client/from-call, call/client/operation-adapter-trait, call/client/from-jsonschema]
scope: broad
risk: low
impact: phase
level: review
---
## Description
Review the alknet-call client/adapter completion (the gap ADR-017 left to
implementation, now specced in `client-and-adapters.md`) for spec conformance,
security-constraint conformance, and pattern consistency. This is the quality
checkpoint at the end of the call-completion batch — the work that unblocks
every downstream consumer (runner, container service, bilateral exchange,
NAPI, agent cross-node dispatch).
### Review Checklist
1. **CallClient conformance** (client-and-adapters.md §CallClient):
- `CallClient` struct with registry, identity_provider, trusted_peer
- `new()` constructs default-deny (trusted_peer: false)
- `trusted_peer()` constructs trusted-peer mode (explicit opt-in)
- `connect()` opens QUIC on ALPN `alknet/call`, returns CallConnection
- Dispatch loop is **shared** with CallAdapter (refactored, not duplicated — ADR-017 §1)
- Connection symmetry (ADR-017 §2): both sides call each other after establishment
- Credentials from Capabilities, not env vars (ADR-014, no-env-vars invariant)
2. **Peer-scoped filtering conformance** (ADR-028):
- Default-deny: op with `remote_safe == false` returns NOT_FOUND to remote peer
- Default-deny: `OperationContext.capabilities` populated only for remote-safe ops
- Trusted-peer mode: all External ops dispatch regardless of remote_safe
- services/list hides non-remote-safe ops in default mode (ADR-028 Assumption 2)
- services/list lists all External ops in trusted-peer mode
- Dispatch-time read over single Layer-0 registry (not a copy — ADR-028 §5)
- `remote_safe` defaults false across all provenance (ADR-028 §4)
3. **from_call conformance** (client-and-adapters.md §from_call):
- Calls services/list then services/schema for each op
- Constructs HandlerRegistration with `provenance: FromCall`
- Forwarding handler sends call.requested via CallConnection
- Subscription forwarding yields until completed/aborted
- `composition_authority: None`, `scoped_env: None` (leaf — ADR-022)
- `remote_safe: false` on FromCall leaves
- Namespace collision = error (DC-3/OQ-28), not silent overwrite
- Re-import on connection establishment (DC-2/OQ-27, v1 default)
- Cross-node abort via parent_request_id (ADR-016 §6)
4. **OperationAdapter trait conformance** (client-and-adapters.md §OperationAdapter):
- `async fn import(&self) -> Result<Vec<HandlerRegistration>, AdapterError>`
- Trait is `#[async_trait]` (async — ADR-017 §5, locked)
- `AdapterError` is `#[non_exhaustive]` + `thiserror::Error`
- Variants: DiscoveryFailed, SchemaParse, Transport, Unauthorized, Conflict
- Trait lives in alknet-call (where the types live), not alknet-http
5. **from_jsonschema conformance** (client-and-adapters.md §from_jsonschema):
- `provenance: FromJsonSchema`, no real handler (placeholder errors if invoked)
- `composition_authority: None`, `scoped_env: None`, empty capabilities
- `remote_safe: false` (provenance default, ADR-028 §4)
- Implements OperationAdapter, no .await in import (pure parse)
- Malformed schema → `AdapterError::SchemaParse`
6. **Adapter location map conformance** (client-and-adapters.md §Adapter Location Map):
- OperationAdapter trait + from_call + from_jsonschema + CallClient in alknet-call
- No HTTP client / HTTP server deps in alknet-call (stays lean)
- from_openapi/from_mcp/to_openapi/to_mcp NOT in alknet-call (deferred to alknet-http)
- MCP stdio not built (security position, not a feature gap)
7. **No-env-vars invariant** (client-and-adapters.md §No-Env-Vars Invariant):
- Credential path: vault → assembly → Capabilities → HandlerRegistration.capabilities → OperationContext.capabilities → handler
- No handler reads outbound credentials from any source other than OperationContext.capabilities
- No `std::env::var` reads in the credential path
- The invariant is enforced by the dispatch path (build_root_context), not runtime convention
8. **ADR conformance (completion-specific)**:
- ADR-017 §1: shared dispatch loop, CallClient own registry (now peer-scoped per ADR-028)
- ADR-017 §2: connection direction independent of call direction
- ADR-017 §3: from_call flow (services/list + services/schema), FromCallConfig prefix/filter
- ADR-017 §5: async trait, bundles not (spec,handler) pairs, to_* are projections not impls
- ADR-017 §6: cross-node abort cascade through from_call handler
- ADR-017 §7: credentials from capabilities (TLS identity, auth token, remote identity)
- ADR-028: default-deny, remote_safe bool, trusted-peer opt-in, dispatch-time read, services/list hide
9. **Security constraints (completion-specific)**:
- Default-deny filtering: remote peer can't trigger capability exposure for non-remote-safe ops
- Trusted-peer opt-in is explicit, never default
- Capabilities non-serializable, never cross the wire (ADR-014)
- from_call trust is transitive (remote node's code runs) — recorded in spec, not enforced beyond scoped env
- FromCall/FromJsonSchema leaves have no composition authority (can't escalate)
10. **Test coverage**:
- Integration test: two-node call (CallClient ↔ CallAdapter, both call each other)
- Integration test: default-deny op → NOT_FOUND to remote peer
- Integration test: remote_safe op dispatches to remote peer
- Integration test: trusted-peer mode exposes all External ops
- Integration test: services/list hides non-remote-safe in default mode
- Integration test: from_call populates Layer 2 overlay, forwarding works
- Integration test: subscription forwarding streams remote events
- Integration test: namespace collision returns error
- Integration test: cross-node abort cascades through from_call handler
- Unit tests: AdapterError variants, OperationAdapter trait compiles
11. **Spec drift check**: verify `client-and-adapters.md` still matches the
implementation after the completion (no spec/impl drift introduced during
implementation). In particular: the CallClient struct sketch, the
CallCredentials sketch, the FromCallConfig fields, the AdapterError
variants, and the remote_safe field on HandlerRegistration.
## Acceptance Criteria
- [ ] CallClient matches client-and-adapters.md (struct, new/trusted_peer, connect, shared loop)
- [ ] Peer-scoped filtering matches ADR-028 (default-deny, trusted-peer, services/list hide)
- [ ] from_call matches client-and-adapters.md (flow, FromCallConfig, provenance, None fields)
- [ ] OperationAdapter trait + AdapterError match client-and-adapters.md (async, non_exhaustive, variants)
- [ ] from_jsonschema matches client-and-adapters.md (provenance, placeholder handler, no I/O)
- [ ] Adapter location map respected (no HTTP deps in alknet-call; from_openapi/mcp not built here)
- [ ] No-env-vars invariant holds (credentials from Capabilities, no env-var reads)
- [ ] ADRs 017 + 028 conformed to (plus 014/015/016/022/023/024 where touched)
- [ ] Default-deny security constraint enforced (no capability exposure for non-remote-safe)
- [ ] Integration tests cover two-node call, default-deny, trusted-peer, from_call, abort cascade
- [ ] No spec/impl drift in client-and-adapters.md (or drift documented + spec amended)
- [ ] `cargo fmt --check -p alknet-call` passes
- [ ] `cargo clippy -p alknet-call --all-targets` passes with no warnings
- [ ] All tests pass
## References
- docs/architecture/crates/call/client-and-adapters.md — the spec being reviewed against
- docs/architecture/crates/call/README.md — crate index (now lists client-and-adapters.md)
- docs/architecture/decisions/017-call-protocol-client-and-adapter-contract.md — ADR-017 (amended)
- docs/architecture/decisions/028-callclient-peer-scoped-registry-filtering.md — ADR-028
- docs/architecture/open-questions.md — OQ-25..28 (two-way-door remainders — verify defaults match spec)
- docs/research/alknet-call-completion/gap-analysis.md — DC-1..4, the decisions this batch resolved
- tasks/call/registry/remote-safe-marking.md
- tasks/call/client/call-client.md
- tasks/call/client/from-call.md
- tasks/call/client/operation-adapter-trait.md
- tasks/call/client/from-jsonschema.md
## Notes
> This review closes the call-completion batch. The load-bearing security
> invariant is ADR-028's default-deny: a remote peer's call must not trigger
> dispatch that populates OperationContext.capabilities from the local
> registration bundle unless the op is explicitly remote-safe. Verify this
> with a test that asserts a non-remote-safe op's call does NOT populate
> capabilities (not just that it returns NOT_FOUND — the security argument is
> about capability exposure, not just call denial). The no-env-vars invariant
> (ADR-014) is the dispatch-side corollary: no handler reads credentials from
> any source other than OperationContext.capabilities. The shared dispatch
> loop (ADR-017 §1) is the architectural commitment that keeps CallClient from
> becoming a parallel protocol implementation — verify the loop is genuinely
> shared (refactored out of CallAdapter), not copy-pasted. If deviations are
> found, document and fix before considering the call-completion batch done.
> This unblocks every downstream consumer, so spec/impl drift here propagates.