l402-discover

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

With readOnlyHint=true and openWorldHint=true already present, the description adds meaningful behavioral details: no payment is committed, the challenge is cached for later reuse, and responses include pricing and payment-method information. It does not contradict the annotations and gives enough context for safe usage.

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 compact and front-loaded: the core action appears first, followed by return-value highlights and the caching behavior. Every sentence earns its place without fluff or repetition.

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 probe tool with one required parameter and no output schema, the description covers what the tool returns, when to use it, and the relevant caching side effect. It does not specify failure behavior or non-L402 endpoints, but those are minor gaps given the overall clarity.

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%, so the schema already documents both parameters and their defaults. The description reinforces that 'url' is the endpoint being probed but adds little about 'method' beyond what the schema provides. 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 uses a specific verb ('Probe') and resource ('endpoint') and states the purpose: discover L402 pricing without payment. It also names concrete outputs (cost in sats, payment methods, credit tiers) and distinguishes itself from l402-pay by mentioning challenge caching. This makes the tool's role clear even among many 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?

The description clearly implies the tool is a pre-payment discovery step: 'without committing to payment' and 'a subsequent l402-pay can reuse it' provide strong context for when to use it. It does not explicitly enumerate exclusions or alternative tools, but the intended workflow is evident.

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