gmail_send

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 and does not discharge it: it never says sending is an irreversible external side effect, whether the message lands in Sent, whether HTML in the body is rendered, or whether an authenticated Gmail session is a prerequisite (the presence of flow_browser_check_session siblings makes that a live question). Only 'via Gmail' gestures at the transport.

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 front-loaded sentence with zero waste: the action and transport come first, the optional-field note second. Nothing is repeated from the schema and no filler is present.

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 five-parameter send tool whose schema is fully annotated, the essentials are nearly covered. What remains missing is material for a side-effecting external action: confirmation/safety expectations, authentication prerequisites, and any indication of what a successful send returns now that there is no output schema.

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%, so all five parameters are already documented, including that CC/BCC take comma-separated lists and the body supports HTML. The description's mention of optional CC and BCC adds the useful nuance that only three fields are mandatory, but goes no further than the schema. 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?

The description gives a specific verb and resource ('Send an email via Gmail'), which is enough to separate it from gmail_search, gmail_read and the Drive/Sheets/Docs siblings. It does not, however, distinguish it from gmail_reply, the other sibling that produces outgoing mail, so an agent must infer that reply is for threading onto an existing message.

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?

Nothing states when to use this instead of gmail_reply or when not to use it. The only usage signal is 'optional CC and BCC', which is a field note rather than guidance, so an agent has to reason about the alternative from the sibling names alone.

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