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

Annotations already establish readOnly, idempotent, and non-destructive behavior. The description adds meaningful behavioral context: 'FREE,' 'discoverable,' 'live x402 prices,' and 'Fresh-State acquisition roles,' which go beyond the annotations and help the agent understand the data freshness and scope.

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 a single, front-loaded sentence that states the core value proposition first ('FREE catalog/pricing surface') and packs the key return items and purpose into the remainder without wasted words.

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?

For a read-only, no-required-param pricing query with an output schema and clear annotations, the description covers what the tool does, why to use it, and its free status. The only notable gap is parameter-level guidance, which is minor for this tool's simplicity.

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%, so the description bears the burden of explaining the parameters. It does not explain 'tier' or 'max_price_usd,' though 'budget' hints at price filtering. The enum values are visible in the schema, but the description adds no semantic meaning 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 description uses a specific verb ('Returns') and names concrete resources: SALT19 products, live x402 prices, schemas, and Fresh-State acquisition roles. It also clearly frames the tool as a free catalog versus paid calls, distinguishing it from cost-incurring siblings.

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 explicitly says the tool is for budgeting 'before choosing a paid call,' giving a clear use case and timing. It does not name specific sibling tools or state when not to use it, but the free-vs-paid framing provides adequate context.

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