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

With no annotations, the description carries the full behavioral burden. It discloses the shape of the data returned (field key, label, type, required, help text, options), which is genuinely useful given there is no output schema. It never explicitly states the operation is read-only, nor does it cover permissions or error behavior.

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, no filler. The return payload is stated first and the follow-up action second, so the most important information is front-loaded and every clause earns its place.

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 discovery tool with no annotations and no output schema, the description supplies what structured data cannot: the exact return fields and the intended follow-up call. The one omission is its relationship to enquiry_describe, which leaves a sibling-selection question unresolved.

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 is nothing for the description to document and the baseline of 4 applies. The detail about keys being used to key answers to submit_enquiry is the only parameter-adjacent information, and it concerns a sibling's inputs rather than this tool's.

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 names a specific resource (the Tools for PPC enquiry fields) and enumerates exactly what each field carries: key, label, type, required flag, help text and allowed options. That is precise enough for an agent to know what it gets back. It stops short of differentiating itself from the sibling enquiry_describe, which an agent could easily confuse it with.

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?

It states the downstream workflow explicitly: 'Pass answers to submit_enquiry keyed by field key,' which tells the agent this is the discovery step before submission. There is no guidance on when to prefer it over enquiry_describe, and no exclusions are given, so it falls just short of a full when/when-not statement.

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