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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description adds valuable behavioral context: pricing and settlement destination come from a live HTTP 402 challenge, not a copied wallet or stale price, which reinforces the open-world, read-only nature and clarifies data freshness.

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 two sentences: the first states the purpose and the second provides a key behavioral constraint. It is front-loaded and free of fluff, though the opening verb 'Explain' is slightly indirect for a quote tool.

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?

Given the simple schema (one parameter, no output schema) and rich annotations, the description covers the source of pricing and freshness requirement. However, it does not clarify what the tool returns (e.g., a challenge, a quote object, or explanatory text) or how to supply the 'capability' parameter, leaving gaps for correct invocation.

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% and the single parameter 'capability' has no description in the schema. The tool description mentions 'paid capability' but does not explain what value to pass (e.g., identifier format, where to find it), leaving the parameter semantics largely undocumented.

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 description states the tool explains how to obtain pricing for a GhostKey/SML paid capability, but does not clearly say it returns a quote or challenge. The verb 'explain' is less direct than 'get' or 'fetch', and there is no explicit differentiation from sibling tools like ghostkey_catalog or ghostkey_policy.

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 implies the tool should be used to obtain authoritative pricing from a fresh HTTP 402 challenge and warns against copied wallets or stale fixed prices, but it does not explicitly state when to choose this tool over alternatives or provide exclusions beyond the freshness caveat.

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