Mark Gmail messages as read

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

With no annotations, the description carries the full burden. It usefully discloses the underlying mechanism (UNREAD label removal) rather than just restating 'mark read', which is real added value. However it omits relevant behavioral context for a mutation: required Gmail modify scope, idempotency/repeat-safety, and the 500-id batch ceiling.

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?

One short, front-loaded sentence with zero filler; every word earns its place. It is arguably under-specified rather than padded, which is a completeness issue rather than a conciseness one.

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 simple single-parameter mutation with no output schema, the description is minimally adequate, but with no annotations and no output schema it should at least note permission requirements or that the operation is idempotent. Nothing an agent needs to call it is strictly missing, but the safety context is thin.

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 description coverage is 100% with a single well-documented 'ids' parameter, so the baseline is 3. The description's 'given messages' adds no format, ordering, or batching detail beyond the schema's own 'Message ids to mark as read.'

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 gives a specific operation (remove the UNREAD label) applied to a specific resource (given messages), and the Gmail label mechanic distinguishes it from gmail_apply_label or gmail_archive. It does not explicitly name a sibling or state why one would choose this over gmail_apply_label with the UNREAD label id, so it falls short of a 5.

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?

There is no guidance on when to use this versus gmail_apply_label (which could achieve the same label removal) or when it is inappropriate. The agent must infer the intended context from the tool name alone.

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