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

With no annotations, the description carries full burden. It discloses cost (free, no credits charged), outputs (relevance score, matched variables, should_check flag), and conditional behavior (next steps based on should_check). It does not mention error handling or side effects, but for a screening tool, the disclosed traits are substantial.

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 compact and front-loaded with the key hook ('Free relevance screen'). Each sentence earns its place: purpose, return value, conditional guidance, cost indication, and auth requirement. No fluff or repetition.

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?

Given no output schema, the description explains return values (score, matched variables) and the should_check flag meaning. It also covers cost and integration with check_action. Missing details like error responses or rate limits, but for the tool's simplicity and with full schema coverage, it is nearly complete.

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 coverage is 100%, so baseline is 3. The description reiterates api_key and the should_check logic, but adds minimal new meaning about parameters themselves. It does not explain action, policy_id, or threshold beyond the schema descriptions, so it does not elevate beyond baseline.

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: a free relevance screen that checks policy variables before a paid check. It uses a specific verb ('checks') and resource ('policy variables'), and distinguishes itself from siblings like check_action and check_action_paid by explicitly positioning it as the preliminary step.

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?

Explicitly instructs when to use it: before running a paid check. It provides conditional guidance based on should_check, telling the agent to run check_action if true and skip the paid check if false. This clearly differentiates from alternative tools and gives actionable usage rules.

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