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

With no annotations, the description carries the full burden and does so: it discloses that this is not a purchase or guaranteed quote, that submission is two-phase with a validation pass first, that the enquiry is not visible to providers until the person clicks an emailed link, and that details go to up to three providers with opt-out rights. It also defines consent verbatim, which is the actual authorization condition.

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 purpose and the two negations, then organized as Step 1 / Step 2 / consent definition, so the critical routing information comes first. It is long, and the full consent text is repeated verbatim from the schema's consent description, which is mild redundancy — though defensible given the agent must echo it to the user.

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 compensates by describing what step 1 returns (summary, consent line, confirmation token) and what step 2 produces (submission plus an email with a click-through link). Nothing an agent needs to complete the two-phase flow correctly is missing.

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 baseline is 3; the description goes beyond it by explaining the sequencing role of 'confirmation' (present only in step 2, after approval) and by tying 'answers' to the field keys returned by enquiry_fields. It adds workflow meaning rather than duplicating the schema's type information.

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?

Names a specific verb and resource (submits an enquiry to What Can I Drive) and immediately bounds it with two negations — 'NOT a purchase, NOT a guaranteed quote' — which separates it from the checkout/quote tools an agent might otherwise reach for. Siblings (enquiry_fields, enquiry_describe) are preparatory, and the two-step framing here makes the distinction clear.

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?

Gives explicit when-to-call instructions per phase: step 1 with answers keyed by field key plus consent=true, step 2 only after the person agrees and with the confirmation token. The gating condition ('only if the person agrees') and the human-facing action (show the summary and consent line) are spelled out rather than inferred.

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