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

Annotations already declare readOnlyHint=true and destructiveHint=false, yet the description adds substantial context beyond them: it is a paid POST endpoint at 0.10 USDC per call on Base via x402 with 10 signed-wallet free calls per rolling 30 days, requires an X-Wever-Wallet-Proof bound to the exact JSON arguments and route, and returns an Ed25519 signed receipt. It also discloses that arithmetic is exact-decimal and that a contract is available at /api/diligence-contract. These are exactly the cost, auth and integrity behaviors an agent needs before calling.

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 opening sentence is well front-loaded, but the remainder collapses output contents, payment scheme, wallet-proof binding, contract path and a human page URL into one dense unbroken paragraph with no separation between purpose, cost and authentication. Each element is individually relevant, but the lack of structure makes it slower to parse than necessary.

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 carries the burden of describing the return: a signed report covering totals (line arithmetic through total), duplicate signals, and fit, plus an Ed25519 receipt. For a nested-object tool with three top-level params this is nearly complete; what is missing is what a failing or indeterminate check looks like (verdict values, error behavior) so an agent can interpret a negative report.

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 description coverage is only 33%, so the description must compensate, and it does: it explains that prior_records drives duplicate detection ('same payee and amount within 7 days of prior_records', repeated lines, ids, transaction hashes, references) and that belongs_to fields are used for fit (payee, payer, currency, budget and cumulative budget, period, due date, reference, scope). This maps parameters to their downstream checks rather than restating types. It stops short of explaining the semantics of individual numeric fields like subtotal vs. line_item amount at a per-field level.

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?

States a specific verb and resource: 'check an invoice or payment record against the job or mandate it claims to belong to.' The scope (record vs. belongs_to, plus prior_records for duplicates) is precise enough to distinguish it from sibling rails such as wever_agent-invoice-rail or wever_diligenceops-paid-run without opening any schema.

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 is implied by the framing ('DiligenceOps', checking a record against the job or mandate it claims to belong to), which suggests pre-payment verification, but there is no explicit when-to-use/when-not statement and no named alternative among the many invoice- and mandate-related siblings. The agent must infer that this is the pre-payment diligence gate rather than a creation or listing tool.

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