file_info

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

Annotations already declare readOnlyHint/idempotentHint/destructiveHint=false, so the safety profile is covered; the description usefully adds that contents are not read and which metadata attributes come back. Error behavior for a missing or out-of-root path is left unstated.

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?

Three short sentences, zero waste, front-loaded with the action and payload before the disambiguation and the read-only confirmation. Nothing could be cut without losing signal.

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?

With no output schema, the description correctly enumerates the returned fields, which is the key omission-risk covered. For a simple two-parameter read-only stat call this is nearly complete; only failure-mode behavior is missing.

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 description coverage is 100% and both parameters are self-documenting, so the schema carries the load. The description's only added signal is the 'approved root' framing, which largely repeats the root parameter's own description; baseline 3 applies.

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 a specific verb+resource (inspect a file or directory) and the exact payload returned (type, size, modification time), plus an explicit scope constraint ('in an approved root'). The 'without reading its contents' clause sharply separates it from read_file, so the agent can route without opening a schema.

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?

Explicitly names the alternative and the condition that selects it ('Use read_file for UTF-8 content'), which is real routing guidance. It doesn't address the other plausible siblings (list_files, search_files) or say what to do when the path doesn't exist, so it stops short of full when/when-not coverage.

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