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

Annotations already cover the safety profile (readOnly, openWorld, non-destructive). The description adds meaningful behavior beyond them: pagination cap ('Up to 50 per page'), cost ('Billed $0.003 per page'), and the shape of returned data including liked_at. Auth/rate-limit behavior is still unstated.

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?

Front-loaded with the primary action, then ordering, identification, return shape, pagination, and cost. Every clause carries information; nothing is wasted or redundant.

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 read-only listing tool with full schema coverage and no output schema, the description covers return contents (full post + liked_at), ordering, page size, cost, and the input constraint. An agent has everything needed to call it correctly.

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 coverage is 100%, so the baseline is 3, but the description adds the mutual-exclusivity constraint (exactly one of username or url) that the schema (0 required params) does not express. That is genuine added semantic value over the structured fields.

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?

States a specific verb and resource ('Get the posts a Bluesky user liked') plus ordering ('newest first') and identification methods. The 'liked' framing inherently separates it from siblings like bluesky_user_posts (authored) and bluesky_post_likes (who liked a post).

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 an input constraint ('provide exactly one of username or url') but no when-to-use guidance or explicit alternatives. Use versus siblings like bluesky_user_posts is only implied by the resource name, so this lands at minimum-viable.

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