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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds genuine architectural context beyond that: credits land on the balance before invoice debits, so over/under/late/duplicate payments become balance states rather than exceptions — useful for an agent predicting what the emitted code does.

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?

Front-loaded with the precondition and the deliverable, and the parenthetical alternative is placed at the end where it belongs. Dense but every clause carries information; only minor cost is the stacked artifact list.

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?

An output schema exists, so return values need no explanation. Preconditions, the sibling alternative, the companion skill, and the runtime semantics of the generated code are all present — nothing an agent needs to invoke this correctly 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 coverage is 100% and both parameters carry enum descriptions, so the baseline is 3. The description restates the three part artifacts ('schema', 'webhook', 'settle') in prose but adds no syntax or format detail beyond what the schema already documents, and never addresses 'framework'.

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 (emits/generates) and a concrete artifact set — ledger schema, cumulative-credit webhook handler, atomic invoice-settle function — for a named resource (top-up wallet integration). It also distinguishes itself from the sibling checkout/plugin path, so an agent can route correctly without opening schemas.

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?

Gives an explicit precondition ('For EXISTING apps') and an explicit when-not with the alternative named ('New store with no users? Use the checkout/plugin path instead'). It also names a companion skill to pair with, leaving no routing ambiguity.

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