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

Beyond the annotations (readOnlyHint=false, openWorldHint=true, idempotentHint=false, destructiveHint=false), the description adds substantive traits: it performs no provider work, callbacks, document retrieval or signed attestations; it grants no authority and never supplies server credentials; and it is a bounded computation on caller-supplied data with USDC/Base settlement. This is unusually rich disclosure of side-effect boundaries for a paid tool.

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 lengthy and badly ordered: it opens with pricing ('Paid URL: 1.00 USDC on Base'), defers the actual purpose to mid-paragraph, then repeats payment-route and authority disclaimers multiple times. Several sentences (credential/mandate caveats, 'existing product credentials... remain required where applicable') restate the same hedging without adding actionable information.

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, and the description only loosely sketches the return ('exact matched and missing items') without format detail. It does cover billing model, free tier, and operating boundaries thoroughly, so an agent can understand cost and scope, but the return contract and input format expectations remain thin.

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 0% at the property level, so the description must carry semantic weight. It establishes the relationship between the two inputs (expected vs available labels are compared to produce matched and missing sets), which the schema alone does not convey, but it adds no format or constraint guidance beyond that.

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 sentence 'Compare explicit submitted evidence labels and return exact matched and missing items' gives a specific verb, resource, and output, and the follow-up 'does not read or verify document contents' usefully distinguishes it from document-analysis siblings. However, the purpose is buried in the middle of pricing and boundary boilerplate rather than front-loaded, which weakens first-glance identification.

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?

It mentions free alternative computation paths ('/api/mcp or /api/service-resolver') and an x402 paid settlement route, but this is cost-route guidance, not when-to-use guidance. There is no explicit statement of when to invoke this versus named siblings such as wever_mcp-diligence-rail, only 'where applicable' hedging about credentials and mandates.

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