Single well-defined tool with clear schema, descriptions, and error handling. Tool follows verb_noun naming convention (execute_js) and has complete input schema with proper type constraints. Description is actionable. Parameters are documented with min/max bounds. Output schema is documented in implementation but not in tool definition metadata. Security considerations are present (forbidden pattern validation). Main gaps: no output schema formally documented in tool definition, no explicit idempotence guarantees, no dry-run/confirmation pattern for safety-critical operation.

• Add formal outputSchema to tool definition: {type: 'object', properties: {result: {type: 'any', description: 'Return value of executed code'}, console: {type: 'array', items: {type: 'string'}, description: 'Captured console.log output'}, executionTime: {type: 'number', description: 'Milliseconds elapsed'}, memoryUsage: {type: 'number', description: 'Heap memory used in bytes'}}}
• Expand tool description to include safety warnings: 'Execute JavaScript code in an isolated sandbox environment. WARNING: Code execution is irreversible and may consume resources. Always review code before execution. Use timeout and memory parameters to constrain resource usage.'
• Add recovery guidance to timeout parameter: 'Maximum execution time in milliseconds (100-30000). If timeout is exceeded, the code is forcibly terminated, partial results may be lost. Retry with a longer timeout or break code into smaller chunks.'
• Add recovery guidance to memory parameter: 'Memory limit in bytes (1MB-100MB). If memory limit is exceeded, execution terminates with OutOfMemory error. Reduce data size, enable garbage collection, or split processing into batches.'
• Implement a dry-run mode or explanation-before-execution pattern for safety-critical use. For example, add optional parameter 'dry_run: boolean' that parses code without executing it, or require explicit acknowledgment via a separate validate_js tool before calling execute_js.
• Document error classifications in code: distinguish between retryable errors (timeout, resource limits) and non-retryable errors (syntax errors, forbidden patterns). Include retry guidance in error messages.