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

No annotations provided, so description carries full burden. Describes simplification effect quantitatively (vertices reduction, no visible difference). States 'safe to embed'. Lacks detail on error handling or permissions, but overall transparent about output characteristics.

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?

Four sentences, each adds critical information: purpose, safety, performance with concrete numbers, and usage advice. No redundant or filler content. Front-loaded with the core action.

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?

Given the complexity (2 params, output schema exists, tool is simple retrieval), the description covers all necessary aspects: what it does, when to use it, parameter effects, and behavioral impact. No gaps identified.

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 100%, so baseline is 3. Description adds value by explaining the impact of the tolerance parameter (constituency polygon shrinks from ~4k to 200-400 vertices). This provides practical guidance beyond the schema's technical description.

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?

Clearly states 'Fetch simplified GeoJSON for a boundary by its ONS census code.' The verb 'fetch' and resource 'simplified GeoJSON' are specific. Distinguishes from sibling 'get_boundary_geojson_by_code' by mentioning 'simplified'.

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?

Explicitly advises to prefer this tool over get_boundary_geojson_by_code() for Leaflet map pages due to context window limits. Provides concrete scenario and alternative. Also notes it's safe for embedding in HTML.

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