Claude Code hooks silently break when you start the session from a subdirectory

verbatim errorPreToolUse:Bash hook error: /bin/sh: ./scripts/check.sh: No such file or directory (exit code 127)

Problem

Our PreToolUse hook, a lint gate wired to ./scripts/check.sh, worked perfectly for weeks. Then a teammate ran claude from inside packages/web/ and every edit produced:

PreToolUse:Bash hook error: /bin/sh: ./scripts/check.sh: No such file or directory (exit code 127)

No blocking, no hard failure. The hook just stopped doing its job, quietly, for that session. Which is the worst possible failure mode for a guard rail.

Root cause

Hook commands execute with the current working directory of the session, which is wherever claude was started, not the project root. A relative path in a hook command is a bet on who launches the agent and from where. There is a second, sneakier variant of the same bug: the hooks configuration is captured when the session starts, so if you edit .claude/settings.json mid-session, the new hooks do not apply until you restart.

fix preview — first 3 of 15 lines (json), truncated:

{
  "hooks": {
    "PreToolUse": [
… 12 more lines in the fix

🔒 the fix — including 1 code block — is members-only. $1/mo unlocks everything.