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

Goes well beyond the annotations: discloses paid URL cost (0.10 USDC on Base via x402), the 10 free signed-wallet calls per 30 days, the X-Wever-Wallet-Proof binding requirement, Ed25519 signed receipt, and critically that it only matches words/figures/dates rather than interpreting meaning. Annotations already carry safety hints, but this adds real operational context. Not a 5 only because rate/limit behaviour on exhaustion is unstated.

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?

Front-loads the core action and scope, then layers payment, auth, and output details. Sentences are long and dense (the brief-contents sentence is a run-on), but no sentence is filler; a small structural trim would help 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?

With no output schema, the description compensates by describing the returned report and its Ed25519 receipt, and by bounding what the report does (matching, not interpretation). It also points to the contract endpoint and human page. Complete enough for correct invocation, short only of explicit error/failure behaviour.

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 100%, so the schema already documents all four parameters including the html/text format default and currency fallback. The description adds little parameter-specific detail beyond restating 'one invoice document,' so baseline 3 is appropriate.

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 ('submit one invoice document') and enumerates exactly what the resulting brief contains (parties, invoice number, dates, line items, totals, arithmetic checks). It is clearly an invoice-briefing tool, though it doesn't explicitly name the sibling it replaces (e.g. wever_invoice-check or wever_agent-invoice-rail), so tie-breaking still requires schema inspection.

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?

Provides useful scoping ('reads only the material in the call: no page fetch, no account access...') and pricing/free-call mechanics, but gives no explicit when-to-use vs alternatives guidance among the many invoice-related siblings. Usage is implied rather than directed.

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