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

Annotations already declare destructiveHint=true and idempotentHint=true, so the mutation profile is known; the description adds genuinely new context: the confirmation-token lifecycle (single token, expires, invalidated by record changes) and a data validation rule that posting accounts must belong to the workspace's current chart. It stops short of describing the outcome of a successful apply or what clearing looks like, so not a 5.

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 critical constraint (apply only the previewed change after confirmation) is front-loaded in the first sentence, and each following sentence adds a distinct rule. Minor waste: the trailing 'Requires confirmation.' restates the first sentence, and 'Prepare setting or clearing...' is awkwardly worded for what is a write operation.

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 destructive, token-gated mutation with no output schema, the description covers the token lifecycle, the confirmation gate, and the chart-of-accounts validation - enough for an agent to call it safely. It omits what a successful call returns or how a cleared default is represented, which would matter for chaining.

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?

Only one parameter with reported 0% schema coverage, but the description compensates well: it says the tool accepts the confirmation_token only and pins the token's provenance to preview_update_client_defaults plus its expiry behavior. That is meaning the bare string type would not convey, though it does not restate the 20-262144 length bounds or the nested 'input' wrapper.

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 (apply) on a specific resource (a client's currency and posting-account default), and immediately names the sibling it is paired with, preview_update_client_defaults. An agent can distinguish it from the many other update_* tools in the sibling list without opening any schema.

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?

Explicit prerequisites: the call must follow a preview and a user confirmation of that preview, and the token must be the exact one returned. It also states the failure path - changed or expired records require a new preview - which routes the agent back to the correct alternative tool.

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