describe_file

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

With no annotations, the description carries the burden of disclosing behavior. It adds useful context: 'no token cost', 'Operates locally with no auth or rate limits', and implies a read-only operation via 'Return'. It does not explicitly state 'does not modify the file', but the described behavior strongly implies non-destructive, which is 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?

The description is moderately sized, front-loaded with the core purpose, and each sentence contributes value (purpose, return fields, operational details, usage guidance, parameter note). It is slightly long but not bloated, and the structure flows logically from what to when to parameter.

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 low complexity (one parameter, no output schema), the description covers the essential aspects: what the tool returns, when to use it, operational constraints, and parameter validation. It does not describe the exact return format, but the list of fields provides sufficient context for a metadata retrieval 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?

Schema coverage is 100% with one required 'id' parameter described as 'File ID'. The description adds 'id' must be a valid integer file ID, which slightly clarifies the required format but is largely redundant with the schema's type declaration. This is a baseline score as the schema already documents the parameter.

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 purpose: returning metadata about a file without pulling its content. It lists specific fields ('Tags, size, est_tokens...') and explicitly contrasts with read_file, making it distinct from sibling tools.

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 when you'd otherwise chain read_file + list_tags + get_history + find_related just to decide whether to actually read the file.' It names alternatives and the exact scenario, making it highly actionable.

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