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

With no annotations to lean on, the description carries meaningful behavioral context: nothing is bought, ordered or paid, no quote is guaranteed, and the call is free. It also previews the returned content (who receives details, consent wording, confirmation flow), which is valuable since there is no output schema. It stops short of 5 only because it doesn't discuss rate limits, freshness, or failure modes.

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 'Read first.' directive is front-loaded and each following sentence adds a distinct claim (no purchase, no guarantee, free, what is returned). It is slightly wordy and self-referential in restating what the tool 'states plainly,' but there is no filler that fails to inform.

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 zero-parameter explainer with no output schema and no annotations, the description supplies enough: it identifies the subject (submit_enquiry's behavior) and enumerates the returned material (recipients, consent wording, confirmation). An agent knows what it will get back, though it could be more explicit that this is a static documentation read rather than live data.

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?

The tool takes zero parameters, so there are no parameter semantics to explain and the baseline is 4. Nothing in the description misrepresents the argument surface, and no parameter-level detail is expected.

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 states a specific function: it 'states plainly what submit_enquiry does on Equipment Rental Compare,' making it clear this is an explanatory/read tool about the enquiry flow rather than the submission itself. It effectively distinguishes itself from the sibling submit_enquiry by framing itself as documentation rather than the action. The framing is slightly meta and the title describes content ('What you get: an ENQUIRY...') rather than the tool's own verb, which keeps it just short of a 5.

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?

'Read first.' gives a directional hint that this should be consumed before acting (presumably before submit_enquiry), but it never explicitly states when to call it versus alternatives like enquiry_fields or submit_enquiry. The routing intent is implied rather than spelled out, so it lands at minimum-viable guidance.

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