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

With no annotations, the description carries the burden and does so well: it discloses the exact return shape (changed_count, next_cursor, as_of, no rows), the cost model (free via x402), and the HTTP method and path. It does not discuss auth setup beyond the x402 price note or any rate limits, which is the only remaining 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?

Front-loads the value proposition and return shape, then usage routing, then compact HTTP metadata. Every element earns its place, though 'Free:' is repeated at the start and again in the price tag, a minor redundancy.

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?

There is no output schema, so the description must explain returns, and it does so precisely (the three fields and the absence of rows). Combined with the trivial single-parameter schema, an agent has everything needed to call and interpret this 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?

Schema description coverage is 100% and the schema already explains 'since' as an opaque cursor from a previous next_cursor with bootstrap-on-omit semantics. The description adds no parameter-level detail beyond that, so the baseline 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?

States a specific verb and resource ('count of federal contract awards changed since your cursor') and immediately scopes it as a probe that returns no rows. It explicitly distinguishes itself from the paid sibling by naming when the delta should be called instead, so an agent can tell the two apart without opening either schema.

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?

Gives explicit when-to-use guidance ('poll hourly for $0') and a clear escalation condition ('call the paid delta only when changed_count > 0'), naming the alternative sibling by implication. Nothing about selection between this and gov_contracts-awards_delta is left to inference.

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