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 ~1 mile radius, the fixed latest-month data window, the aggregation shape (counts by category plus top streets), and the geographic coverage limit (England, Wales and Northern Ireland only). It omits any note on latency, rate limits, or how a Scottish/unknown postcode is handled, which keeps it short of a 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?

Two compact sentences, front-loaded with what is returned and the search radius, followed by the coverage caveat. No filler or restated title.

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?

For a one-parameter read tool with an output schema, the description supplies everything needed to call it correctly: place anchor, radius, timeframe, aggregation, and geographic eligibility. Return-value detail is properly delegated to the output schema.

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?

There is a single parameter at 100% schema coverage, so the baseline is a 4. The description still adds meaning by establishing that the postcode acts as a location anchor with an implied ~1 mile search radius rather than, say, an administrative boundary key.

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 verb+resource (crime counts) and pins the scope precisely: street-level, near a postcode, ~1 mile radius, latest published month, aggregated by category with top streets. That is enough for an agent to separate it from broader siblings such as area_report or full_area_intelligence 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?

Usage context is implied by the stated scope and the 'latest month' freshness constraint, but there is no explicit when-to-use vs alternatives guidance and no named alternative for agents wanting historical months or a wider radius. Nor does it state what happens for out-of-coverage postcodes, which is the one exclusion an agent would need.

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