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

With no annotations provided, the description carries the full behavioral burden. It adds useful context: the call is free, the data comes from paid dispatcher calls, and omitting the URL returns the full list. The read-only nature is evident from 'Show,' though output shape and rate limits are not disclosed.

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 extremely compact, with no filler. It front-loads the cost signal ('FREE'), then states the core behavior, then the parameter behavior. Every sentence earns its place.

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 one-parameter, zero-required read-only stats tool, this is largely complete: action, data source, and list-all behavior are all covered. The absence of an output schema is partially offset by naming the actual stats returned, though aggregation or time-range details are unspecified.

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 schema already fully documents the single optional 'url' parameter, so the baseline is 3. The description adds meaning beyond the schema by clarifying that omitting the URL lists all stats, which directly affects how an agent should invoke the tool.

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 action ('Show') and the resource (success rate and latency stats) with a specific data source (x402dispatcher paid calls). It is distinct enough from sibling metric tools, though it does not explicitly name or differentiate from alternatives.

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 implies when to use the tool—when API performance stats are needed—and provides a key invocation hint ('Omit url to list all'). However, it gives no explicit when-not-to-use guidance or comparison with sibling tools.

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