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

With no annotations, the description carries full burden. It mentions self-pay is flagged, implying exclusion of self-payments. However, it lacks details on edge cases, data freshness, or error conditions, which would improve transparency.

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 concise sentences, front-loaded with the signal name and explanation. No unnecessary words; 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?

For a simple, single-parameter tool, the description is fairly complete: it explains the metric, mentions self-pay flagging, and gives usage advice. Lack of output schema is acceptable as return type is implied.

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 singular parameter 'address' is described in schema as 'Payee address.' The description adds context about the address being the payee for which the repeat rate is computed, but schema coverage is 100%, so baseline 3 is appropriate.

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 defines the tool as computing the 'repeat rate' of payers returning for a second+ settlement. It uses a specific verb ('share of distinct payers') and resource ('x402 settlement to this payee'), and distinguishes from siblings by mentioning use with mainstreet_score.

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?

Explicitly states to use alongside mainstreet_score to separate real demand from wash activity. This provides a clear usage context, though it doesn't discuss when not to use the tool.

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