l402_pay

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

With no annotations at all, the description carries the full behavioral burden, and it does disclose two important traits: it spends real Lightning funds and it consults a token cache to avoid double-paying. It omits failure modes (insufficient balance, amount over limit), whether payments are irreversible, where tokens are cached, and whether the cache is scoped per wallet, which matters a lot for a money-moving tool.

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 short sentences with zero filler, leading with what the tool does, then the cache-avoidance behavior, then the return value. Nothing here needs trimming or reordering.

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 6-parameter tool that spends real money with no annotations and no output schema, the description covers the happy path and the return value but not error behavior or the safety role of max_amount_sats. Adequate to call the tool, thin for calling it safely.

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%, so every parameter including url, force, dry_run, wallet_id, and max_amount_sats is already documented in the schema. The description only restates the cache behavior implied by force. Baseline 3 applies since the schema does the parameter work.

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 and resource: access an L402-protected URL by auto-paying the Lightning invoice. That is clearly distinguishable from generic payment tools. However, it never distinguishes itself from the closely related siblings l402_challenge_create, l402_payment_verify, or pay_invoice, even though the L402 family overlap is the main ambiguity risk.

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 is only implied: an agent holding a URL that returns HTTP 402 is the intended caller. There is no explicit when-to-use/when-not, and no routing advice to l402_challenge_create plus l402_payment_verify for the manual two-step flow, or to dry_run for price discovery before committing funds.

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