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

Annotations already cover readOnly, idempotent, non-destructive and closed-world behavior, so the description's job is to add context — which it does by disclosing the result cap (up to 10 matches), the returned identifiers for chaining into get_school, and the geographic scope (England). It does not cover truncation behavior when more than 10 match, which is the only remaining gap.

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 tightly packed sentences with no filler: the positive scope comes first, the negative constraint and routing come second. Every clause carries operational information, including the result cap and the ID chaining hint.

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 simple two-parameter lookup with no output schema, the description supplies everything an agent needs: what it searches, geographic scope, result limit, the shape of returned identifiers, and how to route to the correct alternative. Nothing material 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 100%, so the baseline is 3, but the description adds real meaning beyond the schema by telling the agent that the area parameter does not accept council or borough names — a constraint not present in the schema text and one that would otherwise cause failed or empty searches. It also clarifies that 'name' is a partial match.

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 (find schools/nurseries/childcare providers by name) scoped to England, and explicitly separates itself from search_near_postcode for geographic 'near X' lookups. It also names the downstream sibling get_school, so an agent can distinguish it from the other four sibling tools without reading schemas.

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?

Gives both when-to-use (name-based lookup, optionally narrowed by town/county/postcode) and when-not-to-use, with a concrete counterexample: council or borough names like 'near Lambeth' should go to search_near_postcode. The alternative tool is named explicitly alongside the condition that selects it.

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