files_get

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

Discloses output format (base64) but misses details like error handling, size limits, or authentication requirements. With no annotations, description carries burden but is minimally adequate.

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?

Two sentences, no fluff. Immediate clarity on what the tool does and how to use it.

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 one-parameter tool, covers purpose and param adequately. Could mention base64 implications or error cases, but not severely lacking.

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?

Only param 'path' described with example ('/Documents/report.pdf'), adding meaning beyond schema. Schema coverage 0% so description compensates well.

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?

States specific verb 'Download' and resource 'file from Fastmail Files' with output format 'base64'. Clearly distinguishes from siblings like files_list, files_upload, files_delete.

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?

Clear that this is for downloading files, implied usage from name and description. No explicit when-not or alternatives, but context suffices for a simple tool.

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