l402_pay

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

With no annotations, the description carries the full burden. It discloses valuable behavioral details: 'Checks the token cache first to avoid re-paying' and 'Returns the response data from the protected resource after successful payment.' However, it omits important side effects (significant financial transaction), behavior of optional parameters like force and dry_run, and error handling (e.g., payment failure, cached token expiration). This is partial transparency but not comprehensive.

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 sentences, front-loaded with the core purpose, and includes only essential behavior (cache check, return response). No filler or redundant information. It is appropriately sized for the tool's complexity.

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 tool with 6 parameters, no output schema, and no annotations, the description is incomplete. It provides a high-level flow but lacks details on optional parameters (force, dry_run, max_amount_sats), expected return format, and edge-case behavior. The presence of related sibling tools (l402_discover, l402_payment_verify) is not leveraged to clarify integration context. An agent invoking this tool would need to infer critical information.

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 only 33% (only url and wallet_id have descriptions). The tool description does not add any meaning for the undocumented parameters (force, method, dry_run, max_amount_sats), and for url and wallet_id it merely restates what the schema already says. The description fails to compensate for the low schema coverage, leaving agents without guidance on the optional parameters.

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 clearly states a specific action: 'Access an L402-protected URL by automatically paying the Lightning invoice.' It also specifies the caching behavior and the return value, distinguishing it from sibling tools like pay_invoice (which only pays) and l402_discover (which finds L402 resources). The verb 'access' plus the resource makes the purpose unambiguous.

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 the tool is used when accessing L402-protected URLs, but it does not explicitly state when to prefer this over alternatives (e.g., pay_invoice, l402_payment_verify) nor when not to use it. It provides context but no explicit exclusions or comparisons, resulting in an implied usage rather than clear guidance.

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