file_info

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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, so the description does not need to restate those. It adds meaningful behavioral context by specifying the exact metadata fields returned and clarifying that contents are never included. Edge cases such as missing files or directory support are not covered, but the central behavioral boundary is clear.

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 a single concise sentence with no filler. It front-loads the key behavior and includes only the information needed to distinguish the tool from content-reading siblings.

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 simple, single-parameter metadata tool with strong annotations, the description adequately covers what is returned and what is not. It falls short of full completeness because it does not explain parameter path semantics or explicitly guide the agent toward read_file for content, but the core calling scenario is sufficiently specified.

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 has one required `file` string with 0% description coverage, and the tool description does not clarify whether this should be an absolute path, relative path, file name, or whether directories are accepted. The parameter is obvious from its name, but the description adds no semantic value beyond the schema already provides.

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 identifies the tool's purpose as returning file metadata (type, size, modified time, Unix mode) while explicitly stating it does not return contents. This distinguishes it from siblings like read_file, making the tool's role 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?

The negative statement 'Does not return contents' implies this tool is for metadata lookups rather than content access, which helps route away from read_file. However, it does not explicitly state when to use file_info over alternatives like list_directory, nor does it name read_file as the sibling for content retrieval.

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