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

Annotations already declare destructiveHint=true, idempotentHint=true and readOnlyHint=false, so the safety profile is covered. The description adds genuinely non-redundant behavior: token expiry/invalidation on changed records and that existing export holds are enforced. The clause "Prepare clearing explicit invoice account coding; client/workspace fallbacks remain" is semantically useful but grammatically murky, costing some clarity.

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 short sentences with the precondition front-loaded and no filler. The middle sentence about "Prepare clearing explicit invoice account coding" is awkwardly worded and slightly interrupts the otherwise tight flow.

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, non-idempotent-looking-but-idempotent mutation with no output schema and one parameter, the description covers the confirmation workflow, token invalidation, fallback behavior and export holds. It stops short of saying what the cleared posting account reverts to or what a successful response contains, but the essentials are present.

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?

With a single parameter and 0% description coverage in the schema metadata, the description compensates by explaining that confirmation_token must come from this operation's preview, is the only accepted input, and becomes invalid if the record changes or the token expires. That goes beyond the schema's field hint, though it doesn't specify token lifetime or format.

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 states a specific verb+resource (clearing the invoice posting account) and explicitly ties it to the exact change produced by preview_clear_invoice_posting_account, distinguishing it from siblings like set_invoice_posting_account. An agent can tell what it does and which preview it depends on 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?

It states the exact precondition (only after the user confirms the preview), the exclusivity of the input ("Accepts its confirmation_token only"), and the fallback when state drifts ("changed or expired records require a new preview"). When-to-use and when-to-re-preview are both explicit.

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