x402_discover_url

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

With no annotations provided, the description carries the behavioral burden and adequately discloses that the tool performs network fetches to three specific well-known paths and returns a unified discovery object. It does not detail error behavior, authentication, or failure cases, but the network-read nature is clear.

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 tight sentences with no filler. It leads with the core action, lists the fetched endpoints, and summarizes the returned object, every sentence earning its place.

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 one-parameter tool with no output schema, the description conveys the essential return fields (chains, wallet, endpoints, prices) and the discovery mechanism. It does not specify the exact output shape or failure behavior, but the tool is simple enough that this is a minor gap.

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% and the single url parameter is already documented with a description and example. The tool description adds no additional parameter semantics beyond restating that the URL is the service base URL, so baseline 3 is appropriate.

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 names a specific verb and resource: discover an x402 service by URL, and enumerates the exact well-known endpoints fetched. It is clear on its own but does not explicitly distinguish itself from the sibling x402_discover_urls, which may cover the plural/multi-URL case.

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 usage: use this when you have a base URL and need discovery details such as chains, wallet, endpoints, and prices. It does not explicitly state when not to use it or mention alternative sibling tools, notably the similarly named x402_discover_urls.

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