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

With no annotations supplied, the description carries the full burden and does disclose a real behavioral trait: the call opens at a facts level, and the "full signed row — every field with its source page and read date" requires settlement via x402 inside the call. That payment-gated tiering and the provenance metadata are genuine value beyond the schema. It stops short of stating error behavior for a missing key or what exactly the unauthenticated facts level omits.

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?

Two tight clauses, front-loaded with the identity of the resource before the access-level detail. The phrase "settles on x402 inside the call" is jargon-heavy and slightly opaque, but nothing is padding.

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 the description needn't catalog return fields, yet it spends its budget doing partly that while leaving the key format, the failure mode for an unknown key, and the resolve_issuer handoff unaddressed. The x402 disclosure is the strongest completeness element; the agent still has gaps before it can call this confidently.

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% for the single required issuer_key, so the description must compensate and largely does not. It conveys only that this is an exact-key lookup rather than a search, with no indication of key format (ticker, CIK, slug) or where such a key is obtained.

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?

"One issuer row by issuer_key" states a specific verb-and-resource pair and adds what the row contains at the facts level (name, tickers, identifiers, status, claim standing, row count). It is clear what the tool returns, but it never distinguishes itself from the sibling resolve_issuer, which an agent could plausibly pick instead.

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 only implied: you invoke it when you already hold an issuer_key and want that single record. There is no explicit when-not guidance, no mention of when to prefer resolve_issuer for name-based lookup, and no statement of what to do if the key is unknown.

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