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

There are no annotations, so the description carries the behavioral burden. It discloses the key behavior that the call is free and returns both total count and estimated cost at the caller's price tier. However, it does not mention pagination, limits, or whether no results return 0, and with no annotations a higher score would require more behavioral detail.

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 efficient sentences with the core purpose and the most important side effect (no charge) front-loaded, then the usage guidance. Every clause earns its place, and it is easy to scan and act on.

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 lightweight count tool with no output schema, the description covers what it returns (total count and estimated cost), how it differs from the main search tool, and the cost property. It is slightly short on edge cases like empty results or behavior when active_only is omitted, but overall it is enough to invoke correctly.

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 description coverage is 0%, so the description must compensate for parameter meaning, but it only references the three concepts (state × trade × geo) and not the per-parameter specifics. Enum values provide some semantics already for state, trade, and geo_type, but active_only and geo_value are undocumented in both schema and description, so the 0% coverage yields a baseline below needing full compensation.

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 uses a specific verb ('Count') with a precise resource ('contractors matching a state × trade × geo query') and explicitly distinguishes its cost-free behavior. It clearly separates this tool from its sibling search_contractors by stating the count purpose and the no-charge property.

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?

The description explicitly says to use it 'to qualify a query before calling search_contractors,' which tells the agent both when to use this tool and points to the alternative. This is a clear routing instruction to the sibling.

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