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

Annotations already declare readOnly, idempotent, non-destructive, open-world, so the safety profile is covered without prose. The description still adds real context beyond them: the upstream source (UK Parliament Members API), the temporal nature of the records (each with start and end dates), and a stated cost of 1 credit.

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?

Front-loaded with the data inventory, then the disambiguating questions and the scope exclusion. Dense but nearly every clause carries information; the audience list ('journalists, researchers and public affairs') is the only slightly expendable element.

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?

No output schema exists, so the description carries the burden of describing return values and does so by enumerating the record types and their date fields. Together with the source API, the scope limit, and the credit cost, an agent has everything needed to decide and call correctly.

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?

With one parameter and 100% schema description coverage, the schema already explains memberId and even points to mp_lookup and constituency_search as sources. The description adds no further meaning about the parameter (e.g. whether peers use the same id space), 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 and resource ('career in Parliament') and then itemizes exactly what the resource contains: seats held, party changes, ministerial and shadow posts, other posts, select committee memberships with start and end dates. An agent can immediately tell this apart from mp_lookup, mp_contact_details, or member_registered_interests without opening a 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?

Supplies concrete example questions ('was X ever a minister?', 'what committees has X sat on?') and an explicit scope exclusion ('Covers parliamentary roles only, not careers outside Parliament'), plus the target audience. It stops short of naming a sibling tool as the alternative, but the boundary is clear enough to route correctly.

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