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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and a closed world, so the safety profile is covered. The description adds that the payload carries the DVSA file date, sources and canonical URL, which is useful context, but says nothing about auth needs, rate limits, or failure behavior for a malformed id.

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 sentences, front-loaded with the return type and content, followed by the accepted input formats. Slightly dense phrasing in the list of id examples, but nothing is wasted.

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?

An output schema exists, so return-value explanation is not required, yet the description still orients the agent on what the text contains. Combined with the concrete id formats, an agent has enough to invoke it correctly; only the id-prefix enumeration and post-search workflow are left to inference.

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 0% for the single `id` parameter, so the description must compensate, and it does: it names three concrete id shapes ('licence:OB1234567', 'company:02155951', 'guide:vet-a-haulier') plus a page URL. That is real added meaning beyond the string/minLength/maxLength constraints, though it does not enumerate all possible prefixes.

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+resource: it returns the full Markdown text of a single result or HaulierScope page. The 'from search' prefix implicitly separates it from the sibling `search` tool, though it never names an alternative outright. An agent can tell what comes back without reading 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?

The phrase 'a result from search' implies the intended workflow (search first, then fetch an id), but no explicit when-to-use or when-not-to-use guidance is given and no sibling is named. The agent must infer that this is the dereference step after `search` rather than a lookup like `get_licence`.

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