feat(pr2): compress-md, caveman persona, squeez update, track-result hook

[claudioemmanuel]

Summary

PR2 of two implementing the squeez token-optimizer roadmap. Stacks on #10 (PR1: context engine). Lands the user-facing pieces that make squeez attack input + output + memory-file tokens at maximum aggression by default.

Merge order: merge #10 first; this PR will then re-target develop and become a clean diff.

What's in PR2

squeez compress-md — pure-Rust caveman markdown compressor

• Line-based state machine (Text / FencedCode / Table) walks input once
• Preserves verbatim: fenced code blocks, inline code, URLs (bare + markdown link targets), headings, tables, list markers, version strings
• Compresses prose only: drops articles, fillers, pleasantries, hedging
• --ultra adds substitutions: with→w/, function→fn, configuration→config, repository→repo, because→b/c, etc.
• Damage heuristic aborts the write if any code block, URL, or heading was lost
• Backups at <stem>.original.md; never overwritten on subsequent runs
• Targets via --all: ~/.claude/CLAUDE.md, ~/.copilot/copilot-instructions.md, $PWD/CLAUDE.md, $PWD/AGENTS.md, $PWD/.github/copilot-instructions.md

Caveman persona (default Ultra)

• Three intensity levels (lite/full/ultra) shipped via include_str! from assets/persona_*.md
• Injected into squeez init banner (Claude Code) and <!-- squeez:start --> ... <!-- squeez:end --> block in ~/.copilot/copilot-instructions.md
• Squeez can't intercept the model's output stream from the hook layer — persona injection is the honest path

auto_compress_md=true (default)

• squeez init runs compress-md --all silently on every session start
• Idempotent: backup written once, integrity check guarantees safety, second run is a no-op when input is already compressed

squeez update

• Self-updater shells out to curl + sha256sum/shasum -a 256 (both already required by install.sh) — zero new dependencies
• Atomic on Unix (.new + rename); on Windows, writes .new + prints move instructions
• --check reports without installing; --insecure skips checksum verification
• SQUEEZ_UPDATE_URL_OVERRIDE for test injection

squeez track-result + posttooluse.sh extension

• New PostToolUse hook tail pipes raw tool JSON into squeez track-result <tool>
• Extracts file paths + errors from Read/Grep/LS/Glob/Bash results into SessionContext
• Future bash calls dedup against this state via the cross-call hint added in PR1
• Always exits 0 — never blocks the agent, even on malformed input

Config additions

persona = ultra              # off|lite|full|ultra (default ultra)
auto_compress_md = true      # default true

Both opt-out — set persona = off and auto_compress_md = false to disable.

Test plan

• cargo test — 230 passing (was 162). Added: test_compress_md.rs (13), test_persona.rs (8), test_track_result.rs (6), test_update.rs (8) + inline unit tests in each new module.
• cargo build --release — clean
• bench/run.sh — 14/14 fixtures pass, including new mdcompress_claude_md (23%) and mdcompress_prose (27%) at <5ms latency
• bench/run_context.sh — 3/3 (PR1 features still work)
• target/release/squeez init — banner shows Persona: ultra + the full persona text
• target/release/squeez compress-md --dry-run --ultra <file> — preserves code/URLs/headings, compresses prose, reports stats
• target/release/squeez track-result Read with synthetic stdin — file path lands in seen_files
• target/release/squeez update --check — fails gracefully (no GitHub releases yet); will work after first release published

Compression numbers

Fixture	Before	After	Reduction	Latency
mdcompress_claude_md.txt (mixed prose + code)	316 tk	246 tk	-23%	3 ms
mdcompress_prose.txt (pure prose)	187 tk	138 tk	-27%	3 ms

Caveman's LLM-based compressor reports ~45% on similar files, but at the cost of an Anthropic API roundtrip per file. squeez does the local pass deterministically in <5ms with no network call.

Risks & mitigations

Risk	Mitigation
compress-md corrupting CLAUDE.md	always-on damage heuristic + backup-on-first-write + integrity check on every output
Auto-compress on every session re-running	idempotent: second pass produces no further reduction; backup never clobbered
Ultra persona too aggressive	configurable via persona = lite|full|off
squeez update on Windows can't replace running .exe	documented .new + manual move shim
track-result slowing PostToolUse	content truncated to 256 KB; pure-Rust scanning; ≤5ms

🤖 Generated with Claude Code