Copy a file

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Goes well beyond the annotations by revealing non-idempotency ('each retry would create another copy'), the fresh-fileId return behavior, default naming quirks, and that comments and permissions are not copied. No contradiction with the annotation hints.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Five dense sentences, with the core action front-loaded. Every sentence earns its place by adding a distinct operational fact—naming defaults, folder exclusion, copied metadata, or retry behavior—with no fluff.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a 3-parameter tool with no output schema, this description provides complete context: return value, supported file types, folder limitation, metadata exclusions, and retry handling. Combined with the schema, the agent has everything needed to invoke it correctly.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The schema already covers all parameters (100% coverage), and the description adds meaningful detail beyond it: name defaults to the original name (not 'Copy of ...'), and parent_id defaults to the original's parent for My Drive files. This enriches the schema instead of repeating it.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

Opens with 'Copies a file and returns the new copy's metadata,' specifying a clear verb and resource. The phrase 'the original is untouched' distinguishes it from move/delete siblings, making its purpose unambiguous.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Provides explicit when-not-to-use guidance: folders cannot be copied, and names the alternative workflow (create_folder + copy_file per file). It also tells the agent to check with search_files before retrying after an ambiguous failure, which is actionable usage guidance.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.