gmail_batch_modify_labels

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

Annotations already declare non-destructive, idempotent, open-world, non-read-only behavior, so the bar is lower. The description still adds real context beyond them: the 25-item cap is a hard operational limit and 'single audit entry' tells the agent the call is recorded as one unit, which matters for gmail_audit_query usage. It does not say what happens on partial failure or whether add/remove are applied atomically.

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?

Three short clauses, front-loaded with the action and its scope, no filler. 'Single audit entry' is slightly cryptic out of context but is the only borderline clause.

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 mutation batch tool with no output schema and 25% param coverage, the agent still lacks the response shape (success/failure per ID?), conflict rules between add and remove, and whether unknown label names are created or rejected. Adequate but with clear gaps.

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 only 25% — only `ids` is described in the schema — so the description must compensate. It does partially: 'messages/threads' maps to the `type` enum and 'label changes' implies add_labels/remove_labels, but it never explains the add-vs-remove distinction, label ID format, or what happens if both are supplied.

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+resource (label changes) with an explicit batch scope (up to 25 messages/threads), which distinguishes it from the single-item gmail_apply_labels. It never names that sibling, so the differentiation is inferred from 'batch' rather than asserted.

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?

One explicit exclusion is given with a redirect ('TRASH stays protected (use trash tools)'), which is genuine routing guidance. However, nothing tells the agent when to pick this over gmail_apply_labels, gmail_batch_trash, or gmail_restore_message, and the message-vs-thread choice is left unaddressed.

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