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

Annotations already indicate non-read-only and open-world behavior, so the description's burden is lower. It adds useful context like the $0.10 cost and the comparison mechanism, but does not disclose whether it writes to KV or rate limits. This is acceptable given annotation coverage, but not richer.

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 concise and front-loaded with the core behavior, followed by cost and an example. Each sentence carries value, though the example endpoint is slightly redundant with the tool name.

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 single-parameter tool with no output schema, the description explains the core operation and pricing but omits what the response looks like (e.g., changed/unchanged) and the meaning of 'prior KV observation.' It is adequate but not fully self-contained.

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 'url' parameter with 0% description coverage. The description only mentions 'URL' without adding meaning beyond the schema, failing to explain accepted formats, edge cases, or how the URL is used in fingerprinting. It does not compensate for the coverage gap.

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 fetches a URL and compares its content fingerprint with a prior KV observation, naming the specific action and resource. It distinguishes from siblings by focusing on change detection, though it does not explicitly contrast with other check 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?

No guidance is provided on when to use this tool versus alternatives like preflight or access_check. The description includes price and an example endpoint but lacks conditions, exclusions, or mention of sibling tools.

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