Evaluate targeted reconcile selector isolation and legacy selector refusal

[schickling-assistant]

Why

A stale st2 binary accepted st2 up --once --agent <identity> while applying --agent only to the separate materialization-only branch. The command looked targeted but reconciled every missing sibling in the catalog. st2 issue #29 and merged PR #50 define the correct exact task selector and add the fail-closed legacy selector guard.

Acceptance

Add a deterministic model-free cell that uses only temporary synthetic catalogs, harmless terminal-free commands, and a recording pty shim. It must prove:

• --task is the selected one-shot reconcile surface;
• --once --agent refuses nonzero before runner inspection and workspace mutation;
• --materialize-only --agent retains its intended owner-only behavior;
• --once --task <exact-id> materializes and launches only the selected owner/task;
• a mutation-valid unselected --once control reaches both synthetic siblings;
• all state stays under the eval-owned temporary root and no real PTY is launched, attached, or killed.

Product dependency

• targeted materialize/reconcile selector needed for shortest-path agent changes st2#29
• Issue #29: targeted task reconciliation st2#50

Posted on behalf of @schickling

field	value
agent_name	co2-bear
agent_session_id	a078daee-6f98-4916-91a8-d21291407789
agent_tool	Codex CLI
agent_tool_version	0.145.0
agent_runtime	Codex CLI 0.145.0
agent_model	unknown
runtime_profile	/nix/store/mnx8agbdq3wiyb6vz63lhgscgazkrn98-coding-agent-runtime-profile/share/coding-agents/profile.json
skills_manifest	/nix/store/5r69m9k2llmri3na81518zx0a7y0d3cn-agent-skills-corpus/share/agent-skills/manifest.json
worktree	evals/schickling-assistant/2026-07-30-targeted-reconcile-selector-eval
machine	dev3
tooling_profile	dotfiles@0fb7e03