url_shorten

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

Describes pricing ($0.01/call) and free tier usage ('50/50 today'), providing cost behavior. No annotations exist, so this partially compensates, but it omits details like rate limits, authentication, or quota reset behavior.

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?

Very concise: two lines covering purpose, cost, and API endpoint. No unnecessary words. However, the inclusion of Chinese text and cost details upfront is slightly mixed; still efficient.

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 tool with no output schema, the description lacks information about the response format, success/error handling, or what the shortened URL looks like. Incomplete for an agent to fully understand tool behavior.

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?

Only one parameter (url) with schema description '原始URL'. The description adds no further meaning beyond the schema, and schema coverage is 100%, so baseline score of 3 is appropriate.

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 includes 'URL缩短' which clearly indicates the tool shortens URLs, and the API endpoint confirms this. While it lacks an explicit verb, the purpose is immediately understandable and distinct from siblings.

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 on when to use this tool versus alternatives (e.g., other URL shorteners). No mention of prerequisites or context for selection.

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