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

Annotations already declare readOnly/idempotent/openWorld, and the description adds substantial non-obvious behavior: it is a paid tool billed $0.002 USDC on Base per successful call and that an unpaid call returns a PaymentRequired object. It also enumerates the returned fields, so the agent knows both the cost model and the payload shape.

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?

A single dense paragraph, but front-loaded with the purpose and use case before the mechanical details. Every clause carries information (query syntax, return fields, pagination, payment), though the sentence runs long and could be split for scanability.

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?

With no output schema, the description carries the return-value burden and does so by listing text, author handle/display name, createdAt, engagement counts, links and a bsky.app URL. Payment mechanics and pagination are also covered, leaving no practical gap for correct 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?

Schema coverage is 100%, so the baseline is 3, but the description meaningfully enriches semantics by spelling out the supported query syntax (from:handle, #tags, since:/until:) that the schema only gestures at as 'Bluesky search syntax'. It also clarifies that cursor is for pagination.

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 ('returns up to 50 public posts matching a query') scoped to Bluesky, immediately distinguishing it from bluesky_feed and bluesky_profile. The query-capability summary makes the tool's niche 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?

Opens with explicit use cases ('real-time social listening, brand/topic mentions and sentiment research'), which tells the agent when this tool fits. It does not name a sibling as the alternative or state when not to use it (e.g., vs. bluesky_feed for timeline browsing), so it stops 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.