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

Annotations already declare readOnlyHint=true, indicating no side effects. The description adds behavioral context by stating 'No key needed', implying open access without authentication. No contradictions with annotations.

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 redundancy. The first sentence immediately states the output, the second adds value (no key, use case). Every sentence 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?

Given the tool's simplicity (1 optional param, full schema coverage, annotations, output schema), the description is complete. It covers purpose, access requirement, and usage context without needing more detail.

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% (single optional parameter), so baseline is 3. The description does not add details about the parameter beyond what the schema's description ('Optional: only return agents at or under this price.') provides, but the tool's overall purpose is clarified.

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 returns 'Real price_per_call_pence for every registered agent', which is a specific verb+resource. It distinguishes from siblings like forcedream_search_agents by focusing solely on pricing, making its purpose 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?

The description provides clear context: 'Useful for budget-aware agent selection before invoking'. This implies when to use it (pre-invocation) but does not explicitly mention when not to use it or compare to alternative tools like forcedream_search_agents. Still, the guidance is direct and helpful.

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