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

Annotations already declare openWorldHint, idempotentHint, and destructiveHint. The description adds valuable protocol behavior beyond that: an initial call yields a payment challenge with currency-specific pricing, and an MPP client pays then calls again. It does not discuss idempotency or charge-reversal implications, but with annotations covering the safety profile this is a strong addition.

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?

Four sentences, front-loaded with the trigger condition, followed by the payment challenge flow and the no-wallet fallback. No sentence is redundant, and the alternative path is placed last as a natural exception.

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?

Covers the critical invocation behavior: precondition, challenge response, currency behavior, retry flow, and fallback path. It does not explain what a successful paid response contains, but without an output schema that is a minor gap given how well the payment flow is described.

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% for both parameters, so the schema already carries parameter meaning. The description does not add syntax or format details beyond the schema, but it does not need to; baseline 3 applies.

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 (pay), resource (full transcript of a job), and precondition (get_job status is 'payment_required'). It also explicitly references sibling get_job, making the distinction from status-checking tools obvious.

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?

Explicitly says when to use it (job in payment_required status) and gives a clear alternative when no MPP wallet exists: show payment_url from get_job instead. The two-step call-without-payment-then-retry flow is spelled out.

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