[subygan]

Summary

Codex's SessionStart hook (parsec up --session-start) did much less than Claude Code's parsec hook SessionStart, and what it did print leaked into the model's context. This brings it to parity.

Before: the hook printed raw text to stdout. Codex surfaces that to the model as a developer message, so lines like proxy already listening on 127.0.0.1:… — nothing to do landed in context. The model also never got the curation note (fold-marker contract), even though Codex traffic is curated (responses.rs fold-back). That's the read-spiral the note exists to prevent.

After: Codex 0.157.1's embedded session-start.command.output schema takes the same fields as Claude Code (systemMessage, suppressOutput, hookSpecificOutput.additionalContext). The new hook::codex_session_start prints exactly that JSON object and nothing else:

	Claude Code	Codex (before)	Codex (after)
Curation note → model (startup/clear/compact, entitled)	✅	❌	✅
Staged trim → model, one-shot (startup/clear)	✅	raw stdout, also on resume	✅
No-key banner (fresh startup)	✅	❌	✅ worded for Codex
Lifetime savings note (fresh startup)	✅	❌	✅ $parsec-savings
Proxy upgrade / revival notices	✅	status text leaked to model	✅ as systemMessage
Fires on clear / compact	✅	❌ (startup|resume)	✅

Other changes

• The Codex hook block passes --port, so the hook revives the port the Codex provider actually routes to (it can differ from Claude Code's).
• If something that isn't parsec holds the port, or anything else fails, the hook now reports it as a message and exits 0 instead of erroring.
• apikey::gate_banner and statusline::lifetime_note take a trim::Source, so their text matches the harness.
• setup::up drops its session_start parameter; main.rs sends --session-start to the new handler.

Deliberately not ported

• First-run auto-setup: it downloads the embedder and writes Claude Code settings.
• No-reread state reset: Codex has no PreToolUse gate recording reads.
• Claude Code's parsec disable switch: parsec disable codex removes the hook entirely.

Upgrade note

The JSON output takes effect as soon as the binary updates. The wider matcher and --port arrive only after re-running parsec setup codex. This is noted in the CHANGELOG.

Test plan

• cargo fmt --check, cargo clippy -p parsec-proxy --all-targets -- -D warnings
• New trim_cli tests: the curation note on startup/clear/compact but not on resume or when unentitled; the trim skipped on resume and delivered on clear (alongside the note); the banner as a Codex-worded systemMessage; stdout is always valid hook JSON
• Existing Codex trim test updated to read additionalContext
• Manual: a real Codex session to check how the branded systemMessage panel renders (it's laid out for Claude Code's display)

Pre-existing failures, unrelated: noreread::tests::grant_is_per_file_cross_surface_and_refunds and compound_command_passes_whole_on_reissue fail on clean main too. Everything else in parsec-proxy passes.