fix: preflight installs and preserve unrelated hooks

install

@@ -94,8 +94,17 @@ def read_json(path: Path) -> dict[str, Any]:
 
 
 def is_coord_hook(item: object) -> bool:
-    return isinstance(item, dict) and isinstance(item.get("command"), str) and (
-        ".coord/" in item["command"] or ".claude/coord/" in item["command"]
+    if not isinstance(item, dict) or not isinstance(item.get("command"), str):
+        return False
+    command = item["command"]
+    return any(
+        endpoint in command
+        for endpoint in (
+            ".coord/hook.py",
+            ".coord/session.py",
+            ".claude/coord/hook.py",
+            ".claude/coord/session.py",
+        )
     )
 
 
@@ -170,7 +179,12 @@ def write_if_changed(
     temporary = path.with_name(f".{path.name}.coord-new-{secrets.token_hex(6)}")
     fd = os.open(temporary, os.O_WRONLY | os.O_CREAT | os.O_EXCL, expected_mode)
     try:
-        os.write(fd, content)
+        remaining = memoryview(content)
+        while remaining:
+            written = os.write(fd, remaining)
+            if written <= 0:
+                raise OSError(f"short write while creating {temporary}")
+            remaining = remaining[written:]
         os.fsync(fd)
     finally:
         os.close(fd)
@@ -209,49 +223,35 @@ def install(target: Path, *, requested_id: str, check: bool) -> list[str]:
     if not target.is_dir():
         raise ValueError(f"target is not a directory: {target}")
     selected_id = project_id(target, requested_id, check=check)
-    drift: list[str] = []
     destination = target / ".coord"
+    planned: list[tuple[Path, bytes, bool]] = []
     for name in CORE_FILES:
-        write_if_changed(
-            destination / name,
-            (HERE / name).read_bytes(),
-            executable=name in EXECUTABLES,
-            check=check,
-            drift=drift,
+        planned.append(
+            (
+                destination / name,
+                (HERE / name).read_bytes(),
+                name in EXECUTABLES,
+            )
         )
-    write_if_changed(
-        destination / "project-id",
-        f"{selected_id}\n".encode(),
-        check=check,
-        drift=drift,
+    planned.append(
+        (destination / "project-id", f"{selected_id}\n".encode(), False)
     )
 
     legacy = target / ".claude" / "coord"
     for name in ("coord", "hook.py", "session.py", "store.py", "workspace.py"):
-        write_if_changed(
-            legacy / name,
-            legacy_wrapper(name).encode(),
-            executable=name == "coord",
-            check=check,
-            drift=drift,
+        planned.append(
+            (legacy / name, legacy_wrapper(name).encode(), name == "coord")
+        )
+    planned.extend(
+        (
+            (legacy / "project-id", f"{selected_id}\n".encode(), False),
+            (
+                legacy / "DESIGN.md",
+                b"Canonical design: [`../../.coord/DESIGN.md`](../../.coord/DESIGN.md).\n",
+                False,
+            ),
+            (legacy / ".gitignore", b"state/\n__pycache__/\n", False),
         )
-    write_if_changed(
-        legacy / "project-id",
-        f"{selected_id}\n".encode(),
-        check=check,
-        drift=drift,
-    )
-    write_if_changed(
-        legacy / "DESIGN.md",
-        b"Canonical design: [`../../.coord/DESIGN.md`](../../.coord/DESIGN.md).\\n",
-        check=check,
-        drift=drift,
-    )
-    write_if_changed(
-        legacy / ".gitignore",
-        b"state/\\n__pycache__/\\n",
-        check=check,
-        drift=drift,
     )
 
     settings = target / ".claude" / "settings.json"
@@ -263,13 +263,29 @@ def install(target: Path, *, requested_id: str, check: bool) -> list[str]:
         )
         + "\n"
     ).encode()
-    write_if_changed(settings, expected_claude, check=check, drift=drift)
 
     codex = target / ".codex" / "hooks.json"
     expected_codex = (
         json.dumps(codex_hooks(read_json(codex)), indent=2, sort_keys=True) + "\n"
     ).encode()
-    write_if_changed(codex, expected_codex, check=check, drift=drift)
+    planned.extend(
+        (
+            (settings, expected_claude, False),
+            (codex, expected_codex, False),
+        )
+    )
+
+    # All source reads, identity checks, wrapper generation and hook JSON
+    # validation complete before the first target replacement.
+    drift: list[str] = []
+    for path, content, executable in planned:
+        write_if_changed(
+            path,
+            content,
+            executable=executable,
+            check=check,
+            drift=drift,
+        )
     return drift
 
 

tests/test_install.py

@@ -64,6 +64,11 @@ class InstallBehavior(unittest.TestCase):
                                             "command": "printf unrelated",
                                             "timeout": 2,
                                         },
+                                        {
+                                            "type": "command",
+                                            "command": "python3 .coord/custom-security.py",
+                                            "timeout": 3,
+                                        },
                                         {
                                             "type": "command",
                                             "command": "python3 .claude/coord/hook.py",
@@ -115,10 +120,20 @@ class InstallBehavior(unittest.TestCase):
                 for hook in group["hooks"]
             ]
             self.assertIn("printf unrelated", commands)
+            self.assertIn("python3 .coord/custom-security.py", commands)
             self.assertEqual(
                 sum("/.coord/hook.py" in command for command in commands), 1
             )
             self.assertFalse(any(".claude/coord/" in command for command in commands))
+            self.assertEqual(
+                (target / ".claude/coord/.gitignore").read_text(),
+                "state/\n__pycache__/\n",
+            )
+            self.assertTrue(
+                (target / ".claude/coord/DESIGN.md")
+                .read_text()
+                .endswith("DESIGN.md).\n")
+            )
 
             canonical = subprocess.run(
                 [str(target / ".coord/coord"), "--help"],
@@ -244,6 +259,23 @@ class InstallBehavior(unittest.TestCase):
             self.assertEqual(record["task"], "smoke-work")
             self.assertTrue(Path(record["actual_path"]).is_dir())
 
+    def test_invalid_hook_json_refuses_before_any_target_replacement(self) -> None:
+        with tempfile.TemporaryDirectory() as temporary:
+            target = Path(temporary)
+            legacy = target / ".claude/coord"
+            legacy.mkdir(parents=True)
+            (legacy / "project-id").write_text("preflight-project\n")
+            sentinel = legacy / "coord"
+            sentinel.write_text("legacy-sentinel\n")
+            (target / ".claude/settings.json").write_text("{ invalid")
+
+            refused = self.run_install(target)
+            self.assertEqual(refused.returncode, 2)
+            self.assertIn("invalid JSON", refused.stderr)
+            self.assertEqual(sentinel.read_text(), "legacy-sentinel\n")
+            self.assertFalse((target / ".coord").exists())
+            self.assertFalse((target / ".codex").exists())
+
 
 if __name__ == "__main__":
     unittest.main(verbosity=2)