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

With no annotations, the description carries the full burden and does well: it discloses the exact return fields, that no rows come back, the free price via x402, and the polling cadence. It stops short of stating rate limits or cursor expiry semantics, so a 4 rather than 5.

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 free/paid distinction and the return-shape summary; every sentence earns its place. The trailing bracketed HTTP/price/docs metadata is useful but slightly elongated.

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?

No output schema exists, so the description compensates by enumerating the return fields, and it also clarifies the cost model and the relationship to the paid delta. An agent has everything needed to call this 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 description coverage is 100% and the sole 'since' parameter is fully documented in the schema (opaque cursor from next_cursor, omit to bootstrap). The description adds no syntax or format detail beyond the schema, so the baseline 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?

States a specific verb+resource ('count of product recalls changed since your cursor') and explicitly scopes the output ('returns changed_count, next_cursor, and as_of only — no rows'), which cleanly separates it from the sibling gov_recalls_delta that returns actual rows.

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 names the alternative plus the trigger for escalating to it ('call the paid delta only when changed_count > 0'). This is exactly the routing information an agent needs.

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