Initial release: aircontext

scripts/on_tool_use.py

@@ -0,0 +1,106 @@
+#!/usr/bin/env python3
+"""PostToolUse hook — lightweight ticker.
+
+Responsibilities (all must complete in well under 100 ms):
+  1. Read AirContext/state.json. If paused, in-progress, or in cooldown, return.
+  2. Estimate active-chain token usage from transcript_path.
+  3. If usage / model_context_window >= trigger.threshold, fork compactor.py
+     in the background and return immediately.
+
+The compactor runs detached so it never blocks Claude's main loop.
+"""
+from __future__ import annotations
+import json
+import os
+import subprocess
+import sys
+import time
+from pathlib import Path
+
+_HERE = Path(__file__).resolve().parent
+sys.path.insert(0, str(_HERE))
+
+from core.config_loader import load_config  # noqa: E402
+from core.state import StateFile  # noqa: E402
+from core.token_estimator import estimate_active_chain_tokens  # noqa: E402
+
+
+def _project_root(payload: dict) -> Path:
+    cwd = payload.get("cwd") or os.environ.get("CLAUDE_PROJECT_DIR") or os.getcwd()
+    return Path(cwd)
+
+
+def _spawn_compactor(project: Path, transcript: Path, session_id: str) -> None:
+    """Detach compactor.py so the hook returns immediately."""
+    compactor = _HERE / "core" / "compactor.py"
+    args = [sys.executable, str(compactor),
+            "--project", str(project),
+            "--transcript", str(transcript),
+            "--session-id", session_id]
+    log_dir = project / "AirContext" / "snapshots"
+    log_dir.mkdir(parents=True, exist_ok=True)
+    log_file = log_dir / "compactor.log"
+
+    if os.name == "nt":
+        DETACHED = 0x00000008  # DETACHED_PROCESS
+        NEW_GROUP = 0x00000200
+        creationflags = DETACHED | NEW_GROUP
+        with log_file.open("ab") as lf:
+            subprocess.Popen(args, stdout=lf, stderr=lf, stdin=subprocess.DEVNULL,
+                             creationflags=creationflags, close_fds=True)
+    else:
+        with log_file.open("ab") as lf:
+            subprocess.Popen(args, stdout=lf, stderr=lf, stdin=subprocess.DEVNULL,
+                             start_new_session=True, close_fds=True)
+
+
+def main() -> int:
+    raw = sys.stdin.read() or "{}"
+    try:
+        payload = json.loads(raw)
+    except json.JSONDecodeError:
+        return 0
+
+    project = _project_root(payload)
+    air = project / "AirContext"
+    config_path = air / "config.yaml"
+    if not config_path.exists():
+        return 0  # uninitialised — nothing to do
+
+    state = StateFile(air / "state.json")
+    snap = state.read()
+    if snap.get("paused") or snap.get("compaction_in_progress") or snap.get("compaction_ready"):
+        return 0
+
+    try:
+        cfg = load_config(config_path)
+    except Exception:
+        return 0  # config broken — UserPromptSubmit will surface it
+
+    cooldown = int(cfg.get("trigger", {}).get("cooldown_seconds", 300))
+    if time.time() - snap.get("last_compaction_unix", 0) < cooldown:
+        return 0
+
+    transcript = payload.get("transcript_path")
+    if not transcript or not Path(transcript).exists():
+        return 0
+    session_id = payload.get("session_id") or snap.get("last_session_id")
+    if not session_id:
+        return 0
+
+    threshold = float(cfg.get("trigger", {}).get("threshold", 0.6))
+    window = int(cfg.get("trigger", {}).get("model_context_window", 200000))
+    method = cfg.get("trigger", {}).get("estimate_method", "char_div_3_5")
+
+    used = estimate_active_chain_tokens(Path(transcript), method=method)
+    if used / max(window, 1) < threshold:
+        return 0
+
+    # Mark in-progress immediately so successive PostToolUse calls don't double-fire.
+    state.update(compaction_in_progress=True, last_session_id=session_id)
+    _spawn_compactor(project, Path(transcript), session_id)
+    return 0
+
+
+if __name__ == "__main__":
+    sys.exit(main())