get_youtube_topics

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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is known. The description adds value by noting 'Free (0 credits)', a behavioral trait not captured in annotations. This gives useful cost-related context beyond the structured metadata.

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 short sentences that convey purpose and cost without any fluff. Every word earns its place, and the structure front-loads the main function. It is appropriately sized for a tool with no parameters.

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 tool's simplicity (no parameters, read-only), the description is complete. It states what the tool returns (topic categories), its purpose (discovery filters), and its cost. An output schema exists, so return structure is covered elsewhere.

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, so the schema coverage is trivially 100% and the baseline score is 4. The description does not need to explain parameter semantics because none exist, and it correctly focuses on the tool's output domain.

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 a specific verb 'Get' and clearly states the resource 'available YouTube topic categories for discovery filters'. This distinguishes it from sibling tools like get_languages or get_games, which focus on other category types. The purpose is unambiguous.

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 phrase 'for discovery filters' provides clear context on when to use this tool, and the cost note 'Free (0 credits)' adds practical guidance. However, it does not explicitly mention when not to use it or cite alternatives, so it falls short of a 5.

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