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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so the safety profile is covered. The description adds genuinely new behavioral context: a free daily allowance followed by a $0.001 USDC x402 charge per call, which is a real cost/threshold constraint an agent should know before invoking.

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 zero filler: capability and role list first, cost model second. Every clause carries information.

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 5 optional parameters, a 100% description coverage and an output schema handling return values, the description covers what an agent needs. It omits one thing worth stating — whether a call with no filters is valid or one filter is required — but that is a minor gap.

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 100%, so every parameter (name, role, limit, status, postcode) is already documented in the schema, including defaults and the role enumeration. The description largely restates that vocabulary rather than adding format or matching semantics, so the baseline 3 applies.

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 ('Find') and resource ('NHS organisations') and enumerates the searchable dimensions (name, postcode/district, role) plus the full set of role types. An agent can distinguish it from sibling nhs-organisations__organisation (single-record lookup) and nhs-organisations__roles from the description alone.

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 implied by the enumerated search keys, but there is no explicit when-to-use statement and no routing to the sibling tools (organisation for detail lookup, roles for role listings). The only non-purpose sentence is about pricing, not selection.

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