discover_service

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

With no annotations provided, the description carries the full burden. It discloses that the operation is read-only ('Read') and that no payment is made ('Free — no payment is made'), which is useful. However, it does not address error handling, authentication requirements, or the case where the manifest is unavailable, leaving gaps in behavioral transparency.

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 concise sentences: the first front-loads the core purpose, and the second adds a clarifying cost note. Every word earns its place with no redundancy or fluff.

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 simple discovery tool with one parameter, no output schema, and no annotations, the description sufficiently covers what the tool does and what the user will learn (routes, prices, payment rails, schemas). It omits edge-case behavior like errors or unavailable manifests, but given the tool's simplicity, it is largely complete.

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?

The input schema already provides a complete description of baseUrl with an example. The tool description reinforces that baseUrl is the service origin but adds no additional syntax or format details beyond what the schema provides. Since schema coverage is 100%, the baseline of 3 applies.

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 explicitly states the action ('Read'), the resource (x402 service's /.well-known/x402 manifest), and the outcome (learn routes, prices, payment rails, response schemas). This clearly distinguishes it from sibling tools like browse_catalog and list_commerce_tools, which focus on different 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 implies this tool is for discovering a service's capabilities before interacting, but it does not explicitly state when to use it versus alternatives or mention any exclusions. The 'Free — no payment is made' note hints at a low-cost operation but does not provide explicit guidance on sibling tool selection.

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