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

Annotations already declare readOnlyHint=true and destructiveHint=false, covering the safety profile. The description adds useful behavioral context by clarifying this is metadata-only ('without downloading its content') and that it enriches lean identifiers into 'complete file details.' This goes beyond the annotations to explain the tool's non-destructive, metadata-focused behavior.

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, front-loaded with the primary action and key constraints. No filler or redundancy. Every word earns its place, making it highly effective and easy to parse.

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?

Given the tool's low complexity (3 params, output schema present, clear annotations), the description is complete. It covers what the tool does, what it does not do (download content), when to use it (to expand lean IDs), and parameter preferences. No critical context is missing for a metadata fetch tool.

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 provides 100% coverage of the three parameters, so the baseline is 3. The description adds value by indicating that file_id is 'preferred' over path, and by explaining that file_id is a 'lean file_id/version_id' returned by specific write operations. This enriches the parameter understanding beyond the schema's basic descriptions.

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?

The description clearly states the tool's function: 'Get full metadata for one bucket file by file_id (preferred) or path, without downloading its content.' It specifies the resource (bucket file), the scope (one file), and explicitly distinguishes from content-downloading tools like bucket_file_read. This is a specific verb+resource statement that differentiates from siblings.

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?

The description provides explicit guidance on when to use this tool: 'Use this to expand the lean file_id/version_id returned by bucket_file_write and bucket_file_write_many into complete file details when needed.' It also implies when not to use it by stating 'without downloading its content,' signaling that content retrieval is out of scope. This clearly directs the agent to appropriate scenarios and alternatives.

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