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

No annotations are provided, so the description must disclose behaviors. It adds cost information ('Costs 1.00 USDC on Base') and input format requirement ('Provide url (http/https)'). However, it does not disclose authentication needs, error behavior, or whether the MP4 link is temporary, leaving some gaps.

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 compact, front-loaded with the main purpose, and each sentence adds useful information (purpose, input format, cost). No wasted words.

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?

The tool is simple with one parameter and no output schema or annotations. The description conveys input, output fields, and cost, but lacks details on response structure and potential errors, making it adequate but not fully 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?

The schema provides only a bare string parameter with no description. The description compensates by listing accepted URL formats (watch?v=, youtu.be, shorts, embed) and requiring http/https, adding practical meaning beyond the 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?

The description uses the specific verb 'Resolve' and clearly states the tool converts YouTube video URLs to MP4 download URLs with metadata. It also lists accepted URL formats, distinguishing it from the sibling youtube_audio by specifying MP4.

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 clearly indicates this tool is for YouTube video URLs and returns MP4, implying use for video rather than audio. However, it does not explicitly name alternatives or exclusions, so it earns a 4 rather than a 5.

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