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

Goes well beyond the annotations: explains the approval segregation rule (same API key, other keys, sign-in, created agents are refused), that payouts run in Stripe test mode until live is switched on, the 404 when payout runs are disabled (cross-referencing list_payout_runs execution.enabled), and credential/workspace requirements. This is rich behavioral context for a mutation tool whose annotations only give generic hints.

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 behavior and mode split are front-loaded, and each sentence carries distinct information (approval rules, test mode, 404, credentials, workspace claim). The prose is dense with long compound sentences, which slightly hurts readability but no sentence is wasted.

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 3-parameter mutation tool with no output schema, the description covers mode semantics, approval flow, environment (test mode), error conditions (403/404), and credential prerequisites. Nothing an agent needs to call it correctly or interpret failures 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%, so baseline is 3; the description adds meaning by stating dry_run defaults to true and that a non-dry-run request needs a period that has ended. It reinforces rather than merely repeats the schema, but adds no format detail beyond what the schema already documents.

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 opening sentence names both modes precisely: report what would be paid vs. actually request the payout, with a specific resource (marketplace ledger, a period). An agent can immediately separate this from approve_payout_run, reject_payout_run, retry_payout_run, or list_payout_runs.

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 states dry_run true (default) yields a report and nothing moves, while dry_run false requires an ended period and hands off to an approver; it also names approve_payout_run and the 403 it produces. Prerequisites (billing write scope, claimed workspace, payout runs enabled) and the 404 condition are spelled out, leaving little to inference.

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