eval: cover packaged pty attach stream

[schickling-assistant]

Why

Terminal UIs need the installed PTY command to expose geometry and terminal bytes as one ordered machine stream. Source-level client tests do not prove that the packaged launcher preserves an inherited descriptor, or that reconnect snapshots remain ordered through the complete remote attach composition.

What

Adds a model-free cell that drives the pty executable on PATH through a real target daemon, installed remote-serve, routed attach, controlled transport drop, reconnect, and exit.

The held-out checks require:

• fd 3 survives the shipped bin/pty launcher;
• initial attach begins with adjacent GEOMETRY, SCREEN frames;
• the same continuous stream begins the replacement route with a fresh GEOMETRY, current SCREEN pair;
• colored screen state, post-drop state, final DATA, and one trailing EXIT remain framed;
• terminal bytes never leak to stdout or stderr;
• every eval-owned process and PTY session is cleaned up.

Rationale

The fixture controls only which local route a synthetic fabric dial returns and when the first transport connection is dropped. It does not import PTY source modules or invoke dist/cli.js. The installed launcher, daemon, remote routing, attach client, snapshot serialization, reconnect loop, and protocol decoder boundary are exercised together.

This specifically models the composition a terminal UI such as Fractal consumes, without mechanically copying the upstream unit suite.

Dependencies and proof

Depends on merged PTY main containing compoundingtech/pty#140 and compoundingtech/pty#141 at d5fabc3917407aeb937a012bd97679c303e18033.

Focused proof against the package built from exact merged PTY commit d5fabc3917407aeb937a012bd97679c303e18033:

• packaged merged PTY main at d5fabc3: SCORE: 7 PASS / 0 FAIL / 7 gating judges
• installed pre-feature pty 0.12.0: expected red; the launcher rejects the fd option and emits no machine frames
• semantic load: 58 maintained folder evals, 11 nested fleet catalogs
• exact 24x80 to 13x47 min-wins geometry, red SGR preservation, current reconnect state, final DATA/EXIT, and clean side channels: pass
• deterministic oracle mutations for wrong geometry, stripped SGR, stale state, DATA after EXIT, truncation, and stdout/stderr contamination: pass
• fixture reset, shell/Node syntax, preflight safety, closed-set mutations, model policy, catalog generation, and diff checks: pass

The composed cell, VRS check, catalog generation, and complete model-free corpus preflight are green against the merged package and the corpus-pinned st2 0fed14b release. The published st2 archive and extracted binary matched their documented SHA256 identities; no gate was weakened or skipped.

Posted on behalf of @schickling

field	value
agent_name	co1-sage
agent_session_id	ed878dac-3735-4276-b3e0-ea1b1cd65291
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/2026-07-31-pty-machine-stream-eval
machine	dev3
tooling_profile	dotfiles@0fb7e03

[schickling-assistant]

Thank you, @nathanherald — the ordered packaged attach-stream contract is merged and now has a durable composition eval with exact geometry, color, ordering, and side-channel mutation coverage. Excellent foundation.

Posted on behalf of @schickling

field	value
agent_name	co1-sage
agent_session_id	ed878dac-3735-4276-b3e0-ea1b1cd65291
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/2026-07-31-pty-machine-stream-eval
machine	dev3
tooling_profile	dotfiles@0fb7e03