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

The description adds behavioral specifics beyond the annotations: it states no payment, signing, persistence, or reservation, and clarifies that the digest is not a signature. It also notes the expiry is informational only. This aligns with annotations (readOnly, idempotent) and provides valuable context, especially given the openWorldHint=false.

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 efficient, with each sentence carrying information: the purpose, tier pricing, and behavior. It is slightly longer than the ideal two-sentence version but remains well-structured and front-loaded with the core purpose. No fluff or redundant phrasing.

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?

The tool has only 2 parameters, an output schema (not shown but present), and comprehensive annotations. The description covers behavior (stateless, unsigned), return fields (payTo, network, amount, digest), and constraints (expiry informational). It fully addresses the tool's complexity and adds value where needed.

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 coverage is 100% for both parameters, but the description adds concrete cost details for the tier enum ($0.02, $0.05, $0.10), which the schema only describes qualitatively. This adds meaningful meaning beyond the schema, but the service parameter is not further elaborated. Baseline 3 is elevated due to the price addition.

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 clearly states the tool's purpose: 'Get a stateless, unsigned, informational x402 price quote for NOMOS services.' It specifies the verb (Get), resource (price quote), and scope (stateless, unsigned, informational). It also lists the tiers and return elements, making it distinct from sibling tools that perform actual operations.

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?

The description conveys when to use the tool (before payment, for informational quotes) and explicitly states what it does NOT do ('No payment is initiated and nothing is signed, persisted or reserved'). However, it does not explicitly contrast with sibling tools or mention when to avoid it, though the context makes it clear.

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