Share Claude and Codex hook scripts (#19755)

## Summary

- add repo-local Codex hooks matching the existing Claude hooks
- move the hook implementations into `scripts/hooks` so both agents
share one implementation
- handle Codex `apply_patch` payloads in the post-edit formatter
- keep other repo-local `.codex` state ignored while tracking
`.codex/hooks.json`

## Validation

- `python3 -m json.tool .claude/settings.json`
- `python3 -m json.tool .codex/hooks.json`
- `bash -n scripts/hooks/session-start.sh`
- `bash -n scripts/hooks/session-start-web.sh`
- exercised `uv run scripts/hooks/post-edit-format.py` with Claude
`Write` and Codex `apply_patch` payloads

.claude/hooks/post-edit-format.py

@@ -1,77 +0,0 @@
-# /// script
-# requires-python = ">=3.12"
-# dependencies = []
-# ///
-
-"""Post-edit hook to auto-format files after Claude edits."""
-
-import json
-import subprocess
-import sys
-from pathlib import Path
-
-
-def format_rust(file_path: str, cwd: str) -> None:
-    """Format Rust files with cargo fmt."""
-    try:
-        subprocess.run(
-            ["cargo", "fmt", "--", file_path],
-            cwd=cwd,
-            capture_output=True,
-        )
-    except FileNotFoundError:
-        pass
-
-
-def format_python(file_path: str, cwd: str) -> None:
-    """Format Python files with ruff."""
-    try:
-        subprocess.run(
-            ["uvx", "ruff", "format", file_path],
-            cwd=cwd,
-            capture_output=True,
-        )
-    except FileNotFoundError:
-        pass
-
-
-def format_prettier(file_path: str, cwd: str) -> None:
-    """Format files with prettier."""
-    try:
-        subprocess.run(
-            ["npx", "prettier", "--write", file_path], cwd=cwd, capture_output=True
-        )
-    except FileNotFoundError:
-        pass
-
-
-def main() -> None:
-    import os
-
-    input_data = json.load(sys.stdin)
-
-    tool_name = input_data.get("tool_name")
-    tool_input = input_data.get("tool_input", {})
-    file_path = tool_input.get("file_path")
-
-    # Only process Write, Edit, and MultiEdit tools
-    if tool_name not in ("Write", "Edit", "MultiEdit"):
-        return
-
-    if not file_path:
-        return
-
-    cwd = os.environ.get("CLAUDE_PROJECT_DIR", os.getcwd())
-    path = Path(file_path)
-    ext = path.suffix
-
-    if ext == ".rs":
-        format_rust(file_path, cwd)
-    elif ext in (".py", ".pyi"):
-        format_python(file_path, cwd)
-    elif ext in (".json5", ".yaml", ".yml", ".md"):
-        format_prettier(file_path, cwd)
-
-
-if __name__ == "__main__":
-    main()

.claude/settings.json

@@ -6,7 +6,7 @@
         "hooks": [
           {
             "type": "command",
-            "command": ".claude/hooks/session-start.sh"
+            "command": "bash scripts/hooks/session-start.sh"
           }
         ]
       }
@@ -17,7 +17,7 @@
         "hooks": [
           {
             "type": "command",
-            "command": "uv run .claude/hooks/post-edit-format.py"
+            "command": "uv run scripts/hooks/post-edit-format.py"
           }
         ]
       }

.codex/hooks.json

@@ -0,0 +1,26 @@
+{
+  "hooks": {
+    "SessionStart": [
+      {
+        "matcher": "startup",
+        "hooks": [
+          {
+            "type": "command",
+            "command": "bash scripts/hooks/session-start.sh"
+          }
+        ]
+      }
+    ],
+    "PostToolUse": [
+      {
+        "matcher": "Edit|Write|MultiEdit",
+        "hooks": [
+          {
+            "type": "command",
+            "command": "uv run scripts/hooks/post-edit-format.py"
+          }
+        ]
+      }
+    ]
+  }
+}

.gitignore

@@ -51,3 +51,7 @@ profile.json.gz
 # IDE
 .idea
 .vscode
+
+# Codex
+.codex/*
+!.codex/hooks.json

scripts/hooks/post-edit-format.py

@@ -0,0 +1,109 @@
+# /// script
+# requires-python = ">=3.12"
+# dependencies = []
+# ///
+
+"""Post-edit hook to auto-format files after agent edits."""
+
+import json
+import os
+import subprocess
+import sys
+from pathlib import Path
+
+
+def format_rust(file_path: str, cwd: str) -> None:
+    """Format Rust files with cargo fmt."""
+    try:
+        subprocess.run(
+            ["cargo", "fmt", "--", file_path],
+            cwd=cwd,
+            capture_output=True,
+        )
+    except FileNotFoundError:
+        pass
+
+
+def format_python(file_path: str, cwd: str) -> None:
+    """Format Python files with ruff."""
+    try:
+        subprocess.run(
+            ["uvx", "ruff", "format", file_path],
+            cwd=cwd,
+            capture_output=True,
+        )
+    except FileNotFoundError:
+        pass
+
+
+def format_prettier(file_path: str, cwd: str) -> None:
+    """Format files with prettier."""
+    try:
+        subprocess.run(
+            ["npx", "prettier", "--write", file_path], cwd=cwd, capture_output=True
+        )
+    except FileNotFoundError:
+        pass
+
+
+def patch_file_paths(command: str) -> list[str]:
+    """Return added or updated file paths from an `apply_patch` payload."""
+    file_paths: list[str] = []
+    current_update_index: int | None = None
+
+    for line in command.splitlines():
+        if line.startswith("*** Add File: "):
+            file_paths.append(line.removeprefix("*** Add File: "))
+            current_update_index = None
+        elif line.startswith("*** Update File: "):
+            file_paths.append(line.removeprefix("*** Update File: "))
+            current_update_index = len(file_paths) - 1
+        elif line.startswith("*** Move to: ") and current_update_index is not None:
+            file_paths[current_update_index] = line.removeprefix("*** Move to: ")
+            current_update_index = None
+        elif line.startswith("*** Delete File: "):
+            current_update_index = None
+
+    return list(dict.fromkeys(file_paths))
+
+
+def edited_file_paths(input_data: dict[str, object]) -> list[str]:
+    tool_name = input_data.get("tool_name")
+    tool_input = input_data.get("tool_input")
+    if not isinstance(tool_input, dict):
+        return []
+
+    if tool_name in ("Write", "Edit", "MultiEdit"):
+        file_path = tool_input.get("file_path")
+        return [file_path] if isinstance(file_path, str) and file_path else []
+
+    if tool_name == "apply_patch":
+        command = tool_input.get("command")
+        return patch_file_paths(command) if isinstance(command, str) else []
+
+    return []
+
+
+def format_file(file_path: str, cwd: str) -> None:
+    ext = Path(file_path).suffix
+
+    if ext == ".rs":
+        format_rust(file_path, cwd)
+    elif ext in (".py", ".pyi"):
+        format_python(file_path, cwd)
+    elif ext in (".json5", ".yaml", ".yml", ".md"):
+        format_prettier(file_path, cwd)
+
+
+def main() -> None:
+    input_data = json.load(sys.stdin)
+    cwd = input_data.get("cwd")
+    if not isinstance(cwd, str) or not cwd:
+        cwd = os.environ.get("CLAUDE_PROJECT_DIR", os.getcwd())
+
+    for file_path in edited_file_paths(input_data):
+        format_file(file_path, cwd)
+
+
+if __name__ == "__main__":
+    main()

scripts/hooks/session-start.sh

@@ -3,5 +3,5 @@ set -euo pipefail
 
 # Dispatch to web hook if running remotely
 if [ "${CLAUDE_CODE_REMOTE:-}" = "true" ]; then
-  exec "$(dirname "$0")/session-start-web.sh"
+  exec bash "$(dirname "$0")/session-start-web.sh"
 fi