gmail.send_message

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

With no annotations, the description carries the full burden of disclosing behavioral traits. It only states the action 'send' without mentioning side effects, authentication requirements, rate limits, or what happens after sending. This is insufficient for an agent to understand the tool's behavior beyond the obvious.

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?

The description is a single concise sentence that front-loads the core purpose. It contains no filler words or redundant information. However, it is so brief that it sacrifices necessary detail, which is a trade-off rather than a pure strength.

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?

Given the tool has four required parameters and no annotations, the description is incomplete. It does not explain how to use the parameters, any prerequisites, or side effects. The presence of an output schema is helpful but does not compensate for the lack of operational context. The description is far from sufficient for an agent to correctly invoke the tool.

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 0%, so the description must compensate by explaining the parameters. It does not: the four required parameters (account, to, subject, body) are not mentioned at all. The only hint is 'from an account', which vaguely relates to the account parameter but provides no semantics.

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 clearly states the verb 'send' and the resource 'email', and the phrase 'from an account' adds scope. It distinguishes itself from sibling tools like list_messages and read_message by indicating a write operation. However, it could be more specific about what 'account' refers to and any additional capabilities.

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 tool versus alternatives, nor any prerequisites or exclusions. The only hint is the tool name and siblings, but the description itself offers no usage direction.

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