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

Annotations already cover read-only/idempotent/non-destructive, and the description adds real behavioral context beyond them: zero cost with no x402 challenge, counts-only with no customer identities ever, and the caveat that paid counters include the house's own proof payments ('plumbing, never revenue'). That is exactly the kind of interpretation an agent needs to report these numbers correctly.

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?

Purpose is front-loaded in the first clause, followed by the counter inventory and then the privacy/payment caveats. It is a dense run-on paragraph with parenthetical nesting, but nearly every clause carries information an agent could not get from the schema or annotations.

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?

With no output schema, the description carries the burden of explaining returns, and it does so by enumerating each counter group plus the Open Book record and unmetered-services list. It stops short of describing the actual response shape or field names, which is the only notable gap for a zero-argument data tool.

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 no parameters, so the baseline is 4. The description correctly offers no parameter discussion and instead spends its words on what the returned counters mean.

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 concrete resource (the machine-readable Services Completed proof-of-work board) and a concrete action (reads live metered counters from each service's published data), then enumerates exactly which counters appear. It is unmistakably different from generic fleet tools, though it never names a sibling (fleet_kpis, fleet_activity, spend_check) to sharpen the boundary.

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?

Usage context is implied by the enumerated contents (proof-of-work / delivery counters), and the description does clarify the payment posture: call directly, no x402 challenge, free. But it gives no explicit when-to-use vs alternatives guidance and no exclusions relative to neighboring fleet or spend tools.

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