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

With no annotations, the description carries the full burden and does well: it states nothing is bought, ordered or paid, that no quote is guaranteed, and that it is free. It also discloses the return content (recipients, consent wording, confirmation method), which compensates for the absent output schema. It stops short of explicitly declaring read-only/non-destructive semantics.

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?

Three sentences, front-loaded with the 'Read first' instruction, with no filler. The wording 'States plainly what submit_enquiry does on SEO for plumbers' is slightly convoluted and the tool's own name is never used, but the size and ordering are appropriate.

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 tool with no output schema, the description covers the essentials: the nature of the operation (non-purchase, free), the guarantee disclaimer, and the kind of information returned. The main gap is that its relationship to the sibling enquiry_fields is never clarified.

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 input schema has zero parameters, so there is nothing for the description to disambiguate. Baseline 4 applies for a no-parameter tool.

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 explains what the tool returns (who receives the details, consent wording, how the person confirms) and distinguishes the enquiry from a purchase, but its main clause describes what 'submit_enquiry' does rather than stating this tool's own action. An agent can infer this is a descriptive/read-only companion to submit_enquiry, but the tool's own verb is never made explicit.

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 an explicit sequencing hint that implies this should be consulted before submit_enquiry, which is useful. However, it names no alternatives (enquiry_fields is never mentioned) and states no conditions for when this tool is not the right one, leaving usage largely implied.

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