🔌Services & Utilities/bundled
Bundled Skill: updateConfig
src/skills/bundled/updateConfig.ts
Prompt Engineering Insight
Project settings and hooks construction skill: long-form procedural prompt with schema checks, jq validation, and live-proof steps.
Techniques Used
step-by-stepstructured-outputguardrails
prompt
Update Config Skill
Modify Claude Code configuration by updating settings.json files.
When Hooks Are Required (Not Memory)
If the user wants something to happen automatically in response to an EVENT, they need a hook configured in settings.json. Memory/preferences cannot trigger automated actions.
These require hooks:
- "Before compacting, ask me what to preserve" → PreCompact hook
- "After writing files, run prettier" → PostToolUse hook with Write|Edit matcher
- "When I run bash commands, log them" → PreToolUse hook with Bash matcher
- "Always run tests after code changes" → PostToolUse hook
Hook events: PreToolUse, PostToolUse, PreCompact, PostCompact, Stop, Notification, SessionStart
CRITICAL: Read Before Write
Always read the existing settings file before making changes. Merge new settings with existing ones - never replace the entire file.
CRITICAL: Use AskUserQuestion for Ambiguity
When the user's request is ambiguous, use AskUserQuestion to clarify:
- Which settings file to modify (user/project/local)
- Whether to add to existing arrays or replace them
- Specific values when multiple options exist
Decision: Config Tool vs Direct Edit
Use the Config tool for these simple settings:
- \
theme\, \editorMode\, \verbose\, \model\ - \
language\, \alwaysThinkingEnabled\ - \
permissions.defaultMode\
Edit settings.json directly for:
- Hooks (PreToolUse, PostToolUse, etc.)
- Complex permission rules (allow/deny arrays)
- Environment variables
- MCP server configuration
- Plugin configuration
Workflow
- 1. Clarify intent - Ask if the request is ambiguous
- 2. Read existing file - Use Read tool on the target settings file
- 3. Merge carefully - Preserve existing settings, especially arrays
- 4. Edit file - Use Edit tool (if file doesn't exist, ask user to create it first)
- 5. Confirm - Tell user what was changed
Merging Arrays (Important!)
When adding to permission arrays or hook arrays, merge with existing, don't replace:
WRONG (replaces existing permissions):
\
\\`json{ "permissions": { "allow": ["Bash(npm:*)"] } }
\
\\`RIGHT (preserves existing + adds new):
\
\\`json{
"permissions": {
"allow": [
"Bash(git:*)", // existing
"Edit(.claude)", // existing
"Bash(npm:*)" // new
]
}
}
\
\\`${SETTINGS_EXAMPLES_DOCS}
${HOOKS_DOCS}
${HOOK_VERIFICATION_FLOW}
Example Workflows
Adding a Hook
User: "Format my code after Claude writes it"
- 1. Clarify: Which formatter? (prettier, gofmt, etc.)
- 2. Read: \
.claude/settings.json\(or create if missing) - 3. Merge: Add to existing hooks, don't replace
- 4. Result:
\
\\`json{
"hooks": {
"PostToolUse": [{
"matcher": "Write|Edit",
"hooks": [{
"type": "command",
"command": "jq -r '.tool_response.filePath // .tool_input.file_path' | { read -r f; prettier --write \\"$f\\"; } 2>/dev/null || true"
}]
}]
}
}
\
\\`Adding Permissions
User: "Allow npm commands without prompting"
- 1. Read: Existing permissions
- 2. Merge: Add \
Bash(npm:*)\to allow array - 3. Result: Combined with existing allows
Environment Variables
User: "Set DEBUG=true"
- 1. Decide: User settings (global) or project settings?
- 2. Read: Target file
- 3. Merge: Add to env object
\
\\`json{ "env": { "DEBUG": "true" } }
\
\\`Common Mistakes to Avoid
- 1. Replacing instead of merging - Always preserve existing settings
- 2. Wrong file - Ask user if scope is unclear
- 3. Invalid JSON - Validate syntax after changes
- 4. Forgetting to read first - Always read before write
Troubleshooting Hooks
If a hook isn't running:
- 1. Check the settings file - Read ~/.claude/settings.json or .claude/settings.json
- 2. Verify JSON syntax - Invalid JSON silently fails
- 3. Check the matcher - Does it match the tool name? (e.g., "Bash", "Write", "Edit")
- 4. Check hook type - Is it "command", "prompt", or "agent"?
- 5. Test the command - Run the hook command manually to see if it works
- 6. Use --debug - Run \
claude --debug\to see hook execution logs
Tags
skillsbundled