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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and non-destructiveness, so the safety profile is covered. The description adds valuable context: the merchant is fixed by endpoint, not by a parameter, and no parameters are accepted—this prevents misuse and clarifies an unusual behavioral trait.

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?

Three sentences pack the essential information with no waste: what the tool returns, why it takes no arguments, and what to do for a different merchant. The most critical fact—'Takes NO parameters'—is front-loaded in the second sentence, and the overall structure is easily scannable.

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 has zero parameters, rich annotations covering safety and idempotency, and an output schema, nothing an agent needs to call it correctly is missing. The endpoint-binding behavior is explicitly clarified, which is the main source of potential confusion.

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?

With zero parameters, the schema alone provides no semantic guidance. The description explicitly states 'Takes NO parameters' and explains why the merchant is fixed by the endpoint, which is essential for an agent to avoid inventing arguments, especially since additionalProperties is true.

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 that the tool retrieves the complete merchant profile, including trust score, policies, compliance, and protocol support. It identifies the resource and scope precisely, but does not explicitly differentiate itself from sibling tools like get_trust_receipt, which appears related.

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 explains when to use the tool: to read the profile of the merchant associated with the current MCP endpoint. It also provides a clear rule for accessing a different merchant's profile by using the same tool on that merchant's endpoint, though it does not mention alternative sibling tools.

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