Check disk space

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

The description adds context beyond annotations by specifying the method ('reads filesystem stats via statfs') and explaining the return status ('ok' or 'warning'). This complements the readOnlyHint and idempotentHint 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?

The description is two sentences long, no wasted words, and front-loads the primary purpose. It is appropriately sized and structured for quick comprehension.

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 presence of an output schema (indicated), the description does not need to detail return values. It covers all necessary behavioral and safety aspects for a simple read-only tool, making it complete.

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%, so the base score is 3. The description adds context about optional thresholds and default path, but does not significantly extend the schema descriptions, which already cover parameter details.

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 reports total, used, and available disk space for a filesystem path, and validates against thresholds. It uses a specific verb ('report') and resource ('disk space'), distinguishing it from potential siblings, though none are listed.

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 explicitly says it is read-only and never runs a shell, indicating safety. It implies usage for checking disk space without harm. Since there are no sibling tools, explicit when-not or alternatives are not needed.

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