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

With no annotations, the description carries the behavioral burden and it does well: it discloses the ordering, the exact per-page cost, and the need to supply exactly one identifier. It does not mention auth or error behavior, but for a read-style list tool the key operational traits are covered.

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?

Three short sentences: purpose, cost, and usage constraint. The core behavior is front-loaded and every clause adds new information without verbosity.

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 simple paginated read with three parameters, the description plus schema covers how to call it, how ordering works, and the cost model. It might have mentioned what account fields are returned, but there is no output schema and the list nature is already implied by 'users who liked.'

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?

Schema description coverage is 100%, so the schema already documents url, pages, and post_id. The description adds the important relational constraint that url and post_id are mutually exclusive and that one is required, which is not visible in the schema's required list.

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 opens with 'Get the users who liked a Bluesky post' – a specific verb and resource – and adds 'newest first.' In a sibling set that includes comments, reposts, quotes, and details for the same post type, this clearly names the exact operation and object.

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?

It states a strict invocation condition ('Provide exactly one of url or post_id') but does not say when to choose this tool over, say, bluesky_post_reposts or bluesky_post_comments. Usage is reasonably implied by the resource being 'users who liked,' but no explicit alternatives or exclusions are given.

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