macaroons_execute

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

With no annotations, the description carries the full burden, and it delivers: it explains the hold-invoice settlement condition, refund on bridge errors or predicate failures, and the no-wallet default that returns payment_required with a real invoice. This is unusually concrete about payment behavior and error paths.

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 dense sentences with the main action first, followed by payment mechanics and the default no-wallet behavior. Every sentence adds information and none repeats schema content.

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?

The complex payment flow, refund behavior, and no-wallet fallback are well covered. However, since there is no output schema, the description could be more explicit about the success return shape and how refund/error responses are surfaced; it only details the payment_required return path.

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%, but the description adds workflow-level meaning around predicate (settlement condition) and resume_macaroon (usable only after a prior payment_required) beyond the parameter descriptions. It still leaves max_spend_sats to the schema, which is acceptable because the schema already documents it.

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 names a specific verb ('Execute') and resource ('paid marketplace capability by capability_id'), and the payment mechanism makes it distinct from sibling search/metadata/purchase tools. It is immediately clear what operation the tool performs.

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 makes the tool's role clear—executing a paid capability and paying via L402—but does not explicitly state when to prefer it over macaroons_purchase or search. Context implies it, but no direct exclusions or alternatives are named.

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