0088: Reopen a terminal session with a new generation

Status: accepted (2026-08-20) · Scope: product tier (core/agents, core/events/v3, commands/agents)

Context

An operator can return to the same conversation after its task lifecycle was marked done and its V3 generation ended. The next prompt proves that the human session is executing again, but some adapters do not deliver another native session-start callback for that conversation.

The documented recovery command was harn agents lifecycle active. It still required an authority-safe live generation, so it refused the exact state it was meant to recover. Task and Git work remained intact, but all coordination writes stayed unavailable for the rest of the conversation.

V3 terminal authority is immutable. Recovery cannot remove session.ended, change its outcome, append new work to its generation, or call the old generation live again.

Alternatives considered

Resurrect the terminal generation. Rejected because events after a terminal make authority ambiguous and violate V3’s single terminal boundary.

Treat the lifecycle command as a native session-start callback. Rejected because the adapter did not supply that signal. Native provenance would claim evidence that Harnery does not have.

Exempt the conversation from the end-turn ritual. Rejected because it hides the coordination failure and leaves task, claim, status, and identity writes unavailable.

Require a new client conversation. Rejected because a follow-up prompt in the existing conversation is normal operator behavior and already proves live execution.

Decision

When agents lifecycle active resolves a human-facing identity with no live generation, it may open a fresh generation only if all of these checks pass:

• the native session identity matches exactly one terminal private producer;
• the terminal producer matches an authoritative terminal generation;
• the prior generation is not delegated, a workflow child, or a subagent; and
• the V3 route and coordination view remain authority-safe.

The new session.started event has derived/high-confidence provenance, verified session_env attribution, and resume.reason: "approved_lifecycle_reopen". The prior terminal remains unchanged. The new generation begins with the compatibility lifecycle default of active and no inherited task text; a following set-task declares the new focus normally.

The command reports both generation IDs and generation_reopened: true. States other than active still fail when no live generation exists, and the error names the active recovery command.

Result

The lifecycle regression marks a task done, records an approved session end, and runs agents lifecycle active against the retired identity. The ledger then contains two session starts, one unchanged terminal for the first generation, and a live second generation. A subsequent task declaration succeeds through normal V3 coordination authority.