Star Gmail messages

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

No annotations are provided, so the description carries the full behavioral burden. "Add" implies a Gmail state mutation, but there is no mention of idempotency (re-starring an already-starred message), permission/scope requirements, how invalid ids are handled, or that the change is reversible via unstar. That is a real gap for a write operation with zero annotation coverage.

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?

Two short sentences, zero waste, with the action front-loaded before the usage hint. Every clause earns its place.

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 trivial one-parameter tool the essentials (what it does, when to use it) are present. But with no annotations and no output schema, an agent still lacks confirmation of the mutation's safety profile and idempotency, so it is adequate rather than complete.

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 schema description coverage at 100% and a single well-documented `ids` array (including maxItems 500 and minItems 1), the schema already does the heavy lifting. The description adds only "given messages," which reiterates rather than extends the schema, so the 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 (adding the STARRED label to messages) that an agent can act on immediately. However, it never distinguishes itself from the sibling gmail_apply_label, which can plausibly achieve the same effect via the STARRED label, so the boundary between the two is left implicit.

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?

"Use for urgent or action-needed mail" gives a usage scenario, which is more than nothing. But it offers no alternatives or exclusions — notably it never says to prefer gmail_apply_label (or vice versa) when a generic label operation would do, leaving the choice to inference.

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