x402_discover_urls

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

With no annotations provided, the description carries the full burden of behavioral disclosure, and it delivers: it reveals the probing targets (/.well-known/x402 and ai-catalog.json), discloses that requests run in parallel (which has rate-limit and load implications the agent should know), and states the return shape is a summary array. Minor gaps remain — no disclosure of failure handling, malformed-URL behavior, or what the summary entries contain — but the core operational traits are honestly surfaced.

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?

Three sentences totaling roughly 40 words, perfectly front-loaded with the core purpose. Each sentence earns its place: batch/parallel scope, probing targets, and return shape. There is zero filler, no repetition of schema content, and no buried critical information — the most important operational fact (parallel batch discovery) leads.

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 single-parameter tool with 100% schema coverage and no output schema, the description covers the essentials: what the tool does, how it operates (which endpoints it probes), and what it returns. The main omission is the contents of the 'summary array' — an agent doesn't know what fields or statuses to expect in the results — and there's no explicit pointer to the singular sibling. Both are minor given the low complexity, but they keep this from a 5.

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%: the urls parameter has a description and concrete examples ('https://svm402.com', 'https://2s.io'). The description adds mild value by explaining what happens to each URL (it is probed for the two discovery files), which enriches the parameter's meaning slightly. No additional format, normalization, or constraint details are needed given the schema already handles it — 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 opens with a specific verb-resource-scope pairing: 'Batch discover multiple x402 services in parallel.' It goes further, specifying exactly what probing occurs (/.well-known/x402 and ai-catalog.json), which makes the tool's behavior concrete. The word 'Batch' and 'multiple... in parallel' clearly differentiate it from the singular sibling x402_discover_url without needing to open either schema.

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?

Usage context is implied through 'Batch... multiple... in parallel' — an agent can infer this is for multi-URL discovery rather than single-URL discovery via x402_discover_url. However, the description never names the sibling alternative or states an explicit when-to-use/when-not-to-use rule. The distinction is inferable but left to the agent to deduce, so it stops short of explicit guidance.

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