Check an x402 endpoint reliability score

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

No annotations, so the description carries the full burden, and it does well: it discloses that the call is paid (small USDC via x402 on Algorand) and requires the AVM_MNEMONIC environment variable. It omits the exact cost, failure behavior, and whether the payment is consumed on error.

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, each earning its place: cost/mechanism, purpose, and environmental prerequisite. The critical constraint (paid call) is front-loaded so an agent sees it before committing.

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 annotations and no output schema, the description covers cost, requirement, and purpose adequately. It could be more complete by hinting at the score's shape or failure modes, but nothing essential to invoking it is missing.

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 100%, including a format hint and example URL, so the schema already documents the single parameter fully. The description adds no syntax beyond what the schema provides, which is the expected baseline here.

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?

States a specific verb ('Returns the ... reliability score') and resource ('target x402 endpoint URL') and the decision it supports. It does not explicitly distinguish itself from the sibling check_x402_reliability_batch, but the singular targetUrl and phrasing imply a single-endpoint check.

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?

Provides clear usage context: 'so you can decide whether to trust it before routing payment to it.' It does not name the batch sibling as an alternative for multiple-URL scenarios, so routing guidance between siblings is incomplete.

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