dev/third_party/pi/packages/agent/docs/work-packages/00-runtime1-removal.md

WP00 — Runtime1 removal

Status

Complete. No tag. Runtime2 is the sole public implementation. Do not release while its execution path is incomplete.

Goal

Make runtime2 the sole public harness implementation, delete runtime1 and its obsolete tests, then stop before adding runtime2 behavior.

Prerequisites

• The approved acceptance/hook redesign and durability handoffs are present in harness.md, values.md, assistant-durability.md, and tool-durability.md.
• Existing tests are evidence, not authority.

Work, in order

1. Reconcile the contract. Fold the approved acceptance/hook redesign into harness.md, including durable starting, atomic hook-free acceptance, driver-owned before_run, before_drive, request-local system-prompt transformation, trusted restore, and removal of process-origin activation semantics. Audit §§0.4, 1.2, 3.1–3.6, 4.1–4.2, 4.5, 5.1–5.2, 5.5–5.6, and Parts 8–9; remove every stale BeforeResumePrepared, before_resume, resumeData, systemPromptOverride, stable-ID routing, reservation, and fresh | continue | resume activation reference. Delete obsolete runtime planning documents once harness.md and linked handoffs own the active contract.
2. Harvest before deletion. Inspect agent-harness-runtime.test.ts, agent-harness-r2/r3/r4.test.ts, and old restore.test.ts. Preserve unique scenarios in the detailed future rows or a temporary categorized inventory; explicitly discard old reservation, before_resume, resumeData, persisted hook prompt override, semantic restore audit, and pre-outcome_ready tool-crash behavior.
3. Remove runtime1-only public members. Delete before_resume, BeforeResumePrepared, resumeData, systemPromptOverride, and stable hook-ID routing. Add the approved before_drive and transform_context shapes. Update telemetry schema source and regenerate its document. Do not implement starting or acceptance behavior here.
4. Switch the factory. Add packages/agent/src/harness/runtime2/index.ts, point agent-harness.ts at it, and add a constructor-selection regression. Verify the experimental coding-agent worker still creates the harness, subscribes to events, and closes it.
5. Delete runtime1 source and tests listed below.
6. Update [Unreleased] on main or a pull-request branch for the public breaking removals and temporarily incomplete factory. Repository policy forbids changelog edits on dev, so WP00 records but does not perform that release-facing step here.
7. Run the retained tests and checks. Fix every failure; do not restore compatibility shims.

Delete

packages/agent/src/harness/runtime/**
packages/agent/src/harness/restore.ts
packages/agent/test/harness/agent-harness-runtime.test.ts
packages/agent/test/harness/agent-harness-r2.test.ts
packages/agent/test/harness/agent-harness-r3.test.ts
packages/agent/test/harness/agent-harness-r4.test.ts
packages/agent/test/harness/restore.test.ts
packages/agent/test/harness/scratch/r1.ts
packages/agent/test/harness/scratch/r2.ts
packages/agent/test/harness/scratch/r3.ts
packages/agent/test/harness/scratch/r4.ts

Retain

• all test/harness/runtime2/** tests;
• Session, Branch, storage, repository, backend-conformance, and instrumentation tests;
• execution assistant/tool/primitives tests;
• config, hooks, events, telemetry, compaction, and branch-summary code/tests;
• types.test.ts, updated for the reduced public contract;
• packages/agent/src/agent-loop.ts unchanged.

Do not parameterize obsolete runtime1 suites against runtime2 and do not keep a runtime1 smoke suite.

Acceptance

• No source import references harness/runtime/*.
• Public AgentHarness.create() selects runtime2.
• Runtime2 creation, events, inspection, close, and fault tests pass.
• These coding-agent tests pass:
  • experimental-remote-runtime.test.ts
  • experimental-session-worker-manager.test.ts (the upstream replacement for the removed experimental-session-worker.test.ts)
  • experimental-session-worker-lifecycle.test.ts
• Every modified test passes individually.
• Agent and root TypeScript pass.
• git diff --check and npm run check pass.

Outcome

• The accepted hook/drive contract is normative in harness.md; stale acceptance/resume contracts are absent.
• Runtime1 source, validating restore, obsolete suites, and R1–R4 scratch scenarios are deleted.
• AgentHarness.create() resolves through runtime2/index.ts; a constructor-selection regression proves it.
• The scenario harvest added missing tool-close, identity-preflight, recovery-ordering, turn-bracket, and telemetry cases to future rows.
• Upstream added two real remote prompt tests after this handoff was drafted. They remain present but skipped with an R2 re-enable requirement because runtime2 execution is intentionally incomplete. Worker creation, attachment, lifecycle, operation correlation, and close coverage passes.

Non-goals

• No bound-value/list implementation.
• No implementation of starting or atomic acceptance.
• No drive owner, provider, retry, deferred, or tool execution.
• No runtime1 parity work, compatibility layer, archaeology tag, or release.

Stop condition

Stop once runtime1 is absent, runtime2 is the public factory, retained coverage is green, and all checks pass. Report the deletion and harvested scenarios; do not begin another work package.