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

Annotations already cover the safety profile (readOnlyHint, idempotentHint, destructiveHint=false, openWorldHint=false), so the bar is lower. The description still adds real value by disclosing what comes back (official code, level, page URL) and that matching data layers are also returned — important because there is no output schema. It stops short of 5 by saying nothing about result ordering or limits.

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 sentence with the action front-loaded and no filler; the entity enumeration earns its place by defining scope. Slightly packed, but nothing is wasted.

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 usefully covers return contents (code, level, URL, data layers), which is the main completeness gap it needed to fill. Minor omissions remain around the undocumented limit parameter and whether full postcodes are required, but nothing essential to invoking the tool is missing.

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 50%: query is documented in the schema with examples (Dalston, Leeds, E8) while limit (default 8, max 20) is undocumented anywhere. The description adds no detail on either parameter, so the undocumented limit/result-count behavior remains opaque.

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 ("Find UK places ... and postcodes by name") and enumerates the covered entity levels (nations, regions, councils, constituencies, towns, wards, neighbourhoods), which tells an agent this is a multi-level name/postcode search rather than a single-entity fetch. It does not explicitly contrast with siblings like get_place or lookup_postcode, so it stops short of a 5.

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?

Usage is only implied: the agent can infer this is the tool for finding places by name or postcode, but there is no explicit when-to-use, no exclusion of alternatives (get_place, lookup_postcode, compare_places), and no statement about what to do when no match is found. Adequate but with clear gaps.

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