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

Annotations already declare readOnly, idempotent, non-destructive and openWorld, so the safety profile is covered. The description adds genuine context beyond that: the returned components (question and answer text, asker/answerer, dates, holding vs corrected answer, attachments), the upstream API, and a cost of 1 credit. It stops short of describing failure behavior for invalid or missing ids.

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?

Purpose and id source are front-loaded in the first clause, and the return contents follow in a compact list. The id-vs-UIN warning and cost note are somewhat duplicative of structured fields, so it is efficient but not maximally lean.

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 one parameter, no output schema, and safety fully covered by annotations, the description usefully enumerates what comes back, which is the main gap it needed to fill. Only minor gaps remain, such as how attachments are represented or what happens on an invalid id.

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% and the single id parameter already documents 'int, required, written question id ... not the UIN'. The description repeats that same id-vs-UIN distinction rather than adding new syntax or format meaning, so the schema is doing the heavy lifting and 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: get one UK parliamentary written question including the government's full answer. It distinguishes itself from written_question_search (the id source) and from adjacent siblings like unanswered_written_questions, so an agent can select it without opening the 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?

Clearly frames this as a follow-up lookup whose id comes from written_question_search, and explicitly excludes UIN-based lookup, which is the most likely mistake. It does not spell out a when-not-to-use case (e.g., bulk retrieval), but the routing context is clear.

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