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

With no annotations at all, the description carries the full burden and does unusually well: it discloses the per-call cost ($0.005 USDC), the data provenance (ONS, police, FSA), the temporal window of the crime data (last month), and the OGL licensing. It does not say what happens with an invalid or non-existent postcode, whether empty result sets are returned for sparse areas, or anything about latency, so it is not complete.

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?

The definition is short and front-loaded: the use trigger and payload contents come first, with pricing and the related tool last. It is telegraphic but every clause carries information; only the price/related cross-sell adds tangential weight.

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 no annotations, so the description is the only source of return-value information and it does list the four data blocks returned. Pricing and provenance are also covered. The remaining gap is input-side: the accepted postcode format and failure behavior are unaddressed.

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% for the single required parameter, so the description must compensate and largely does not. It never states the expected postcode format (spaced vs. unspaced, case, partial outcodes), even though that is exactly the kind of detail an agent needs to supply a valid value. The only information conveyed is that the input identifies a UK location, which is already obvious from the tool name.

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?

The description names a specific resource ("UK postcode profile") and enumerates the returned datasets: ONS geography and codes, lat/lon, police street crime for last month by category, and nearby FSA food hygiene ratings. That is far more than a restatement of the name and lets an agent tell it apart from the uk_company/uk_leads family. It stops short of a 5 because differentiation is only made against one sibling (property prices).

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?

"Use this for a UK postcode profile" is an explicit trigger condition, and "Related: Property prices: /uk-property" routes the agent to the sibling when property data is what is actually wanted. There are no explicit when-not conditions (e.g. non-UK postcodes, or areas with no crime/food data), so it falls short of a full 5.

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