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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint=false. The description adds the explicit 'read-only' and 'no private endpoints are called' guarantees, reinforcing the safety profile, and mentions the output (readiness score, issues, fixes) which is useful behavior beyond annotations. No contradiction 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, front-loaded with the core purpose and safety guarantee, then parameter usage. Every word earns its place; no fluff.

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 moderate complexity (3 params, 1 required) and the presence of an output schema, the description adequately covers actions, inputs, outputs, and safety. It doesn't need to explain return values since output schema handles that.

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?

Input schema covers all three parameters with descriptions, achieving 100% coverage. The description only restates that url is passed and marketplace_url and expected_resources are optional, adding no new semantic detail. Baseline 3 for high schema coverage applies, with no compensatory info.

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?

Description clearly states a read-only scan of a public API/provider URL for x402, OpenAPI, pricing, and agent-discovery metadata, distinguishing it from sibling tools by naming the resource type and the specific metadata categories. The verb 'scan' and the output (readiness score, issues, fixes) make the tool's 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 for when to use it: for scanning a public API/provider URL, with optional marketplace and expected resources. It does not explicitly contrast with sibling tools like probe_x402_paid_path or check_agent_tool_readiness, and does not mention exclusions or alternative selection criteria.

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