Assess conditional adapter removal after Pi 1.0.2 native MCP parity #1454

Active target — Pi 1.0.1 (3 October 2026)

Rui authorised retargeting and implementation to exact Pi 1.0.1, upstream git head a7229ddc21810d6245105978033b7df645ecc2f7. This supersedes the earlier 1.0.0 execution target below. Preserve all 0.99.1 and 1.0.0 receipts as historical evidence; they are not 1.0.1 qualification.

Source migration, exact-package admission and isolated Bun-only synthetic qualification are authorised. Keep Adapter/Auto as the default, reject unsupported native combinations, retain failed-teardown/Apply security gates, and exclude pi-durable. Live accounts, deployment, production installation, restart and canary remain separately authorised. Do not waive unresolved native, provider or Delegate acceptance gates.

Earlier target and requirements (retained)

Checkpoint: 958ac185255840ee4f800becc5f7e3111ef9acda on feat/mcp-settings-host; stable 0.99.1 source baseline, not 1.0.0 admission.

Shared target and MCP policy

Selected target: Pi 1.0.0, gitHead a13d35a742c6ef8462812a28fbe1d8c8b7431c32. Rui explicitly authorised retargeting all remaining work on 1 October 2026: stabilise and commit current work → update relevant issues/dependencies → resume the 1.0.0 upgrade on that checkpoint. Source changes, isolated dependency installs and offline qualification are authorised; runtime admission remains an acceptance gate, not an assumed result. All new execution is Bun-only. Live accounts/MCP/provider calls, production installation, deployment/restart and experimental pi-durable activation still require separate approval. Preserve completed 0.99.1 receipts and closed issue states as historical evidence; do not relabel them as 1.0.0 results.

• Preserve the approved consolidated instance MCP settings: adapter/native selector, adapter default, exactly one active owner, codemode Auto/On/Off default Auto.
• Engine switching aborts active turns and reloads all extensions through supported public APIs, retaining chats/history; no service restart. Unsupported combinations reject with explicit reasons; no silent fallback or dropped settings.
• Ten native public-API gap diagnostics persist in the 1.0.0 assessment. Target selection is not a capability/security waiver.
• Old Harness/Pico3 exports are removed. Design the pi-durable 1.0.0 Harness successor and HC/PC crosswalk #1493 owns the pi-durable semantic/authority design and Qualify pi-durable 1.0.0 storage and Harness semantics on Bun without activation #1494 its isolated qualification. Do not add pi-durable to production merely to repair imports.

Summary

Dormant conditional adapter-removal work. Begin only after a future explicit removal decision, native parity and matching Delegate qualification. This does not block the current selectable-engine release.

Parent: #1442

MCP contract: #1444

Dependencies

• Blocked by Admit exact Pi 1.0.0 and migrate current-loop removed import boundaries #1492
• Blocked by Preserve MCP prompts, Apps, resources and bounded results on Pi 1.0.2 #1449
• Blocked by Provide keychain-backed MCP OAuth and web/headless sign-in on Pi 1.0.2 #1450
• Blocked by Implement instance MCP settings, engine switching and codemode on Pi 1.0.2 #1451
• Also requires Delegate parity and an explicit future adapter-removal decision.

Acceptance Criteria

• Treat removal as conditional future work, not a prerequisite for the approved selectable-engine release. Keep the adapter default and package available until parity and explicit removal approval exist.

• Packaging must load only the selected implementation at runtime; retaining two available implementations must not create two active owners.

• Only after explicit future adapter-removal approval, remove adapter dependency/lockfile entry, require/config/cache imports, factories, explicit extension paths and old timeout patch only after replacement coverage passes.

• SDK and CLI inventory shows exactly one /mcp owner and one tool/connection registry; collision fails closed with no automatic fallback.

• Migrate docs, seeded examples, skills/prompts/tests/automation from mcp proxy/direct prefixes to native discovery and the approved management/auth path.

• Resume/fork of historical transcripts handles obsolete tool names without rewriting history, guessing targets or reconnecting a hidden server.

• Keep previous matching core/Delegate artifacts and reference-only config for rollback, never simultaneously loaded.

Implementation Notes

Primary known seams: package.json, runtime/src/agent-pool/session.ts, secure/mcp-keychain.ts, mcp-status-hint-adapter.ts, mcp-timeout-patch.ts, bundled-adapter tests, docs/mcp.md and Delegate child loading. Use a bounded repository inventory to catch packaging and tests; do not claim absence from source search alone—inspect the built artifact.

Estimate: S · Risk: medium · Source file: package.json

Source anchors: Piclaw baseline, upstream release, MCP guide, public extension options.

Test Plan

• MCP-15 artifact/lockfile/package scan, registration census and process count.
• Updated bundled/native SDK/CLI/Delegate loading tests and migration-guidance checks.

Definition of Done

• Acceptance criteria satisfied with exact-version evidence
• Required tests/typechecks pass (documentation-only changes use structural/link review)
• Docs and migration guidance updated
• Operational impact and rollback assessed
• Update history and parent/dependency status reflect evidence