stat

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

Description states 'Read-only, no side effects', which aligns with annotations (readOnlyHint: true) and adds concrete details about what metadata is returned, providing helpful context beyond annotations.

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 sentences, no wasted words. Purpose is front-loaded, followed by safety note, then usage guidance with alternatives. Every sentence is essential.

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 metadata tool with good annotations, the description covers what it returns, when to use, and alternatives. No output schema needed; description suffices.

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 is 100% coverage, but description adds context that paths should be files (not directories) by contrasting with 'ls' for multi-file listings, adding value beyond schema.

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?

Description clearly states 'Return detailed file metadata' with specific attributes (size, permissions, owner, timestamps, inode, device). It also distinguishes from sibling 'ls' by noting it is not for directory listing.

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 states when to use ('inspect file attributes without reading file contents') and when not ('Not for directory listing'), with explicit references to alternatives 'ls' and 'du'.

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