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

With annotations already covering the safety profile (destructiveHint=false, idempotentHint=true), the description still adds non-obvious behavior: the first 5 calls/IP are free, failed target connections do not throw tool errors, status_code>=500 forcibly overrides the verdict to 'sla_breach_confirmed', and omitting tx_hash yields a probe-bound rather than payment-bound receipt. These are exactly the rate-limit, error-semantics, and side-effect details annotations cannot express, and nothing contradicts them.

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?

Three dense sentences with the core purpose front-loaded, then behavioral rules, then sibling routing, then an example. Every clause carries information, though the middle sentence is heavily packed and could be split for readability.

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?

An output schema exists so return values need not be explained, and the description still covers the gaps an agent needs: the post-payment precondition, the free-call quota, non-throwing failure behavior, and the two receipt modes. Complete for a 3-parameter, open-world audit 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?

Schema coverage is 100%, so the baseline is 3, but the description adds decision-relevant semantics beyond the schema: what passing tx_hash cryptographically binds (Base/Solana payment signature) and that omitting it still verifies liveness, plus the verdict-forcing effect of status_code. It reinforces rather than merely restates the field docs.

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?

Names a specific verb+resource (audit a paid x402/A2A provider post-payment) plus the concrete outcome (confirm delivery or mint an HMAC-SHA256 signed SLA-breach receipt). It is unmistakably distinct from assay_preflight, assay_probe, and assay_get_ledger_policy, which are named explicitly.

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?

Gives an explicit when-to-use gate ('Use only after paying a provider') and routes the agent to each alternative by condition: assay_preflight before payment, assay_probe for public indexing, assay_get_ledger_policy for policy history. Nothing is left to inference.

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