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

The description goes beyond the annotations (readOnlyHint, openWorldHint) by detailing what the tool returns: reputation tier, human-readable reasons, settlement rail, host, buyer retention stats, and shared_wallet behavior. It also explains the semantics of 'shared_wallet' and advises caution. This fully discloses the tool's behavior and output, exceeding the basic annotation hints.

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 front-loaded with the main purpose, then provides detailed return information. It is slightly longer than minimal but each sentence adds meaningful context (e.g., shared_wallet explanation, buyer retention). It is well-structured and avoids redundancy, though a slight trim could improve conciseness.

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 lack of output schema, the description thoroughly explains the return values: reputation tier, reasons, settlement rail, host, buyer retention, and shared_wallet semantics. It also provides guidance on interpretation. It could be more explicit about the exact response structure (e.g., JSON format), but the semantic coverage is strong for a tool with this complexity.

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?

The input schema has 100% coverage with a clear description of the 'pay_to' parameter format. The tool description adds value by explaining the parameter's role in context: 'Pass the pay-to address a service asked you to pay.' This workflow context enhances the schema's technical description, earning a score above the baseline of 3.

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 purpose: 'Check a recipient wallet BEFORE your agent pays it — a pre-payment guard.' It specifies the verb ('check') and resource ('recipient wallet'), and distinguishes from sibling tools (directory_stats, find_paid_service, get_service) by being the only one focused on wallet reputation. The return details (reputation tier, reasons, rail info) further clarify its role.

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 explicitly says to use this tool before paying a recipient, positioning it as a 'pre-payment guard.' It provides context ('Pass the pay-to address a service asked you to pay') and suggests action ('An unknown or low-reputation recipient is a reason to pause'). It does not list explicit alternatives, but the sibling tools are distinct in purpose, so the usage context is clear.

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