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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the description does not need to re-state the safety profile. It adds meaningful transparency about data provenance and freshness ('sourced line-by-line to named GOV.UK/HMRC pages, re-checked 14 August 2026'), which helps an agent trust the results. It does not disclose pagination or result-count behavior beyond 'short answers', but this is not critical for a read-only search.

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?

The description is two sentences, both high-signal: the first scopes the resource and topics, the second gives provenance and the routing instruction. No filler or repetition of schema fields.

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 lightweight read-only search tool, the description covers what the tool returns, its scope, provenance, and where to go for full detail. The absence of an output schema is mitigated by 'Returns the matching questions with short answers'. A mention of mtd_scope as a sibling for scope-related queries would make it fully complete, but is not essential.

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 schema already documents query and limit. The description adds value by giving concrete example query strings ('when do landlords have to start', 'quarterly deadline', 'penalties for missing an update'), which clarifies intended input semantics beyond the schema's generic 'question or topic'.

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?

The description opens with a specific verb and resource — 'Search 35 plain-English answers about UK Making Tax Digital for Income Tax' — and enumerates covered topics and key details (thresholds, dates). It also distinguishes itself from get_mtd_answer by stating that it returns matching short answers, not full text.

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?

The final sentence explicitly routes agents needing full text and sources to the sibling get_mtd_answer, giving a clear alternative and selection condition. This is direct usage guidance within the description itself.

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