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

With no annotations, the description carries the full behavioral burden. It does disclose that data is live/real-time and free (no billing cost), which is genuine added context. It says nothing about authentication requirements, rate limits, or whether values are cumulative or windowed, though for a zero-argument read-only stats endpoint the risk surface is small.

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?

A single front-loaded clause naming the resource and its metrics, with the salient facts ('Live', 'Free') placed at the edges. No waste, though the telegraphic style and trailing 'Free.' read slightly like marketing copy rather than specification.

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?

There is no output schema, so the description must indicate what comes back, and it does by listing the three metrics. For a zero-parameter, zero-annotation stats endpoint, remaining gaps (units for 'volume', time window) are minor.

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 tool takes zero parameters, so the schema offers nothing to interpret and the baseline of 4 applies. The description does not need to explain inputs and correctly spends its words on outputs instead.

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 names a specific resource (402Proof platform stats) and enumerates the three metrics returned (total payments, volume, active agents). It is readily distinguishable from every sibling, none of which report aggregate platform statistics. It stops short of an explicit 'this is the only aggregate-stats endpoint' differentiation, but the verb/resource pair is clear.

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?

'Live' and 'Free' implicitly signal when to reach for this tool: a zero-cost, no-parameter snapshot of platform-wide numbers, as opposed to the per-entity siblings (get_invoice, verify_payment, bureau_public_score). There is no explicit statement of when not to use it or of an alternative, so the guidance is implied rather than stated.

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