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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), so the bar is lower; the description still adds useful behavior by disclosing that rows carry failure reasons and that revertability is reported — a direct hook into revert_account_settings_batch. It does not say what happens for an unknown or expired batch_id, nor whether large batches are truncated.

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 return contract and the trigger condition in two tight clauses, no wasted preamble. The appended Chinese sentence (繁中) duplicates the purpose rather than adding information, which is a small amount of redundancy in an otherwise efficient definition.

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?

No output schema exists, but the description compensates by naming the return shape (timing, source, counts, revert status, per-row failure reasons) and by anchoring the call to apply_account_settings. Missing only edge-case behavior (invalid/expired batch_id, pagination of very large batches) for full completeness.

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?

One required parameter with 100% schema coverage, so the schema already defines batch_id and even its provenance ('batch_id from apply_account_settings'). The description only restates that it selects exactly one batch — marginal value over the schema, so 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 and resource ('Returns one batch by batch_id') and then enumerates the returned facets: send time, origin channel (website/API/MCP), counts, revertability, and per-row result plus failure reason. That level of detail distinguishes it from get_account_settings, list_account_settings, and revert_account_settings_batch 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?

Gives explicit trigger conditions: 'Applies after apply_account_settings, or when the user asks what a bulk change did,' and points to apply_account_settings as the source of batch_id. It lacks an explicit when-not (e.g. 'use get_account_settings for current state, not batch history'), so it stops short of full alternative routing.

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