youtube_capabilities

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

There are no annotations provided, so the description carries the full burden. It implies a read-only informational nature but does not explicitly state the tool performs no side effects or is safe to invoke. However, given its nature as a capability descriptor, the implication is strong enough for a 3.

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?

A single, tightly scoped sentence that is front-loaded with the core purpose and ends with a direct call to action. Every word earns its place with no redundancy.

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 tool with no parameters and no output schema, the description is sufficiently complete. It conveys the purpose and when to use it. Could mention what type of output it returns, but since it's a probe of capabilities, that is less critical.

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 tool has zero parameters, matching the baseline of 4. The description doesn't need to explain parameters, and it adds value by clarifying the purpose without any ambiguity.

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 states exactly what the tool provides: an explanation of what the APIs can and cannot answer. It clearly distinguishes itself from sibling tools that perform specific API operations, positioning this as a meta-tool for capability understanding.

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 instructs when to use it: 'Read this before concluding a metric is missing,' giving a clear trigger condition. It doesn't need alternatives since it's a standalone informational tool, and the context signals reinforce this by having zero parameters.

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