docs: implementation plan (TTY precedents folded in); task decomposition (17 tasks)

Plan updated with the alknet-tty findings: the drainer pattern
(single ordered writer) makes outbound chunk-boundary parsing sound;
TestStdinSink's try_send→Full→Pending is the inbound backpressure
precedent; OQ-01(a) now cites the reference.

Task graph (taskgraph-validated, 17 tasks, 6 generations, no cycles):
- tasks/server/: core-types, auth, healthz-decoy, adapter
- tasks/gateway/: dispatch, routes, publish
- tasks/websocket/: byte-adapter (research POC), upgrade-session, overlay-ops
- tasks/adapters/: from-openapi, from-jsonschema, to-openapi, from-wss, mcp
- tasks/client/: http-host
- tasks/infra/: integration-suite (phase 4)

Critical path runs through server core → adapter → WS session →
overlay tests → integration suite. High-risk tasks are the three WS
tasks, de-risked by the ws-byte-adapter POC blocking upgrade-session.

tasks/adapters/mcp.md

@@ -0,0 +1,45 @@
+---
+id: adapter-mcp
+name: from_mcp + to_mcp (mcp feature)
+status: pending
+depends_on: [client-http-host, gateway-routes]
+scope: broad
+risk: medium
+impact: component
+level: implementation
+tags: [adapters, mcp, phase-3]
+---
+
+## Description
+
+Port both MCP adapters from
+`/workspace/@alkdev/alknet/crates/alknet-http/src/adapters/{from_mcp/`,
+`to_mcp.rs}` behind the `mcp` feature (rmcp, streamable HTTP only —
+ADR-037). from_mcp: tools/list discovery, per-tool HandlerRegistration
+(Mutation, HandlerKind::Once, FromMCP leaf), structuredContent-preferred
+output handling, ContentBlock-union fallback, isError→CallError.
+to_mcp: 4 fixed gateway tools (search/schema/call/batch — Sub AND Pub
+excluded), StreamableHttpService into axum under /mcp with bearer
+middleware. Shared dispatch spine with to_openapi via GatewayDispatch.
+
+## Acceptance Criteria
+
+- [ ] Both adapters behind `mcp`; default features compile without rmcp
+- [ ] from_mcp round-trip against a mock MCP server (tools/list, tools/call, structured + content-block outputs)
+- [ ] to_mcp: 4 tools listed; call dispatch filtered by ACL; Pub/Sub ops excluded
+- [ ] stdio transport not present anywhere (dependency audit)
+- [ ] `cargo test --all-features` passes
+
+## References
+
+- docs/architecture/http-mcp.md
+- docs/architecture/decisions/037-mcp-stdio-transport-exclusion.md, 041-mcp-tool-gateway-pattern.md
+- Old source: `/workspace/@alkdev/alknet/crates/alknet-http/src/adapters/from_mcp/`, `to_mcp.rs`, `tests/from_mcp_integration.rs`
+
+## Notes
+
+> Agent fills during implementation.
+
+## Summary
+
+> Agent fills on completion.