like_video

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

With no annotations, the description carries the full burden of behavioral disclosure. It only says 'Like a YouTube video' and does not mention authentication requirements, idempotency, side effects, or error behavior. For a mutating action, this is a significant gap.

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 a single sentence with no redundant wording and the action is front-loaded. It is concise and easy to parse, though it would benefit from additional context without becoming bloated.

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 a write operation with no annotations, no output schema, and only minimal description. While the single parameter is well covered by the schema, an agent cannot determine whether authentication is needed, whether liking is reversible, or what a successful response looks like, so the description is not complete enough for safe invocation.

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 input schema already documents video_id as 'Video ID or URL to like' with 100% coverage. The tool description adds no additional parameter meaning beyond what the schema provides, so the 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 uses a specific verb ('Like') and resource ('YouTube video'), so the core action is clear. It is distinguishable from the search/get/list siblings, but it does not explicitly differentiate itself from add_to_playlist, since liking can be viewed as adding to a Liked playlist.

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 gives no guidance about when to use like_video versus alternatives. It only states what the tool does, with no exclusions, prerequisites, or mention of sibling tools like add_to_playlist or subscribe_channel.

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