list_likes

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It clearly indicates a read-only operation ('Returns a list') and the required input (message_id), but it does not disclose error behavior, authentication requirements, or what happens if the message has no likes. For a simple read operation, this is adequate but not thorough.

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, immediately front-loaded with the action and result. Every word earns its place, with no redundancy or filler.

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 fully documented parameter. The description states the return type ('list of users') clearly. Without an output schema, it could specify whether user IDs or full user objects are returned, but the core purpose is sufficiently complete for a straightforward list tool.

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 has one parameter, message_id, with 100% coverage via its description 'Message ID.' The tool description adds no additional meaning beyond this, so the baseline score of 3 applies.

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 clearly states the tool's function: 'Returns a list of users who liked a message.' The verb 'Returns' and the specific resource 'list of users who liked a message' distinguish it from sibling tools like like_message (performs the like) and get_messages (lists messages).

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 implies when to use the tool (to retrieve users who liked a message) but gives no explicit when-to-use or when-not-to-use guidance, nor does it mention alternatives. There is no context about prerequisites such as requiring an existing message_id, making the usage guidance merely implied.

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