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

The description explicitly states 'Free, read-only — resolution does not move money,' reinforcing the readOnlyHint annotation. It adds context about 'provable sources only' and the demo endpoint, which goes beyond the annotation's raw flags. 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?

Three sentences with no fluff: purpose, parameter requirements, and safety/demo tip. Front-loaded with the main action. Every sentence adds value.

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?

The description covers purpose, parameter usage, and safety. It implies the return is an IBAN/BIC endpoint. It could elaborate on the exact output structure, especially with no output schema, but it's sufficiently complete for an agent 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 coverage is 100%, so baseline is 3. The description adds semantic linkage between parameters (EITHER merchant_id OR business_id with business_id_type) and clarifies the 'demo' type value, which is not in the schema. This extra context lifts it above 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 states a specific action ('Resolve a European business to its verified payment endpoint') and clearly names the resource (AsterPay's Merchant Payment Endpoint). This distinguishes it from siblings like check_agent_trust or market_rates, which serve different purposes.

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?

It gives clear usage context: 'Provide EITHER a merchant_id OR a business_id together with its business_id_type' and lists valid types. The demo tip adds practical guidance. It doesn't explicitly state when to avoid this tool, but the parameter combination rules are strong guidance.

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