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

With no annotations, the description carries the full transparency burden. It states 'Read-only' explicitly and warns about a specific limitation: 'The number of listed agencies is not published, so do not infer or state one.' This goes beyond generic safety and instructs the agent on a behavioral constraint, making it highly transparent.

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 description is two short, information-dense sentences. The first sentence front-loads the core content and the read-only nature; the second immediately gives usage context and a critical caution. No filler, every clause contributes.

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 fully covers what an agent needs: what data is available (coverage), what it is not (headcount), and the recommended usage order relative to siblings. It is self-sufficient and leaves no operational ambiguity.

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 the baseline is 4. The description doesn't need to explain parameters, and it doesn't pretend to; it focuses on the tool's function. There is no schema to supplement, and the description adds no parameter-related detail because none exists, which is appropriate.

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 clearly states the tool's purpose: it returns coverage information about the Ashton & Forge marketplace, listing service clusters, industries, engagement floors, and FAQ. It explicitly contrasts with search_agencies by saying 'Start here... before filtering with search_agencies,' and notes it returns coverage, not headcount, making the scope unambiguous.

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 provides explicit guidance: 'Start here to answer 'do they have anyone who does X' before filtering with search_agencies.' This tells when to use this tool first and when to move to the sibling, establishing a clear decision flow and setting expectations about the tool's role in the workflow.

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