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

Goes well beyond the readOnly/idempotent annotations: discloses Blind Mode privacy normalization, a credit cost of 1 per call, an unauthenticated preview capped at 5 rows and 20 calls/day, and — critically — that the upstream dataset is empty so every surface returns the notice and no records. That last point is exactly the kind of behavior an agent cannot infer from schema or annotations.

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?

Purpose is front-loaded, which is good, but the origin notice is long and repetitive, restating the same pause across four surfaces ('the API, the MCP tool, x402 and the Apify actor') in a second sentence that mostly repeats the first. The signal is valuable; the phrasing is padded.

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, and the description does not describe the returned record shape — a real gap for a 7-filter search tool. It does cover the two things an agent most needs (no personal data, and that the feed is currently empty), but the undocumented filter parameters leave the calling contract incomplete.

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 0% across 7 parameters, so the description carries the burden and only partially meets it. It explains 'q' (searches all text fields) and that filters AND together, but leaves 'authority' (an opaque number — ID or name?), 'reference', the decision_date_after/before formats, and page/per_page pagination behavior completely unexplained.

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 — planning applications from planning.data.gov.uk, normalized to one schema — which distinguishes it from the other query_uk_* siblings by domain. However, the bulk of the text is a data-availability notice rather than a purpose statement, and the tool currently returns no records at all, which muddies what an agent should expect.

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?

Offers partial usage mechanics: 'Filters combine with AND; q searches all text fields.' But there is no explicit when-to-use or when-not guidance, no named alternatives, and no statement of what to do instead given the dataset is empty (e.g., use list_sources or another source).

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