gmail_send_message_strict

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

Annotations already declare readOnly=false, openWorld=true and idempotent=false; the description usefully adds the confirm_send=true safety gate and the HTML rendering behavior (multipart/alternative with plain fallback). It does not mention irreversibility, quota/rate limits, or auth scope, but with annotations present the bar is lower.

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?

Four short sentences, front-loaded with purpose, then the hard requirement, then the HTML behavior, then the workflow preference. No filler or repetition.

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 10-parameter, non-idempotent, outbound-email mutation with no output schema, the description omits what the call returns (message id/thread id) and the semantics of thread_id and attachments. It covers the safety gate but not enough of the call/response contract.

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 30% across 10 parameters, so the description needs to compensate and largely does not. It restates confirm_send and is_html, which the schema already documents, while leaving thread_id (does it thread the message or create a new one?), to/cc/bcc constraints, and body format entirely unexplained.

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 ("Directly sends a Gmail message") and adds a differentiator: "This is the only direct-send tool." That implicitly separates it from gmail_create_draft and gmail_send_draft, though the siblings are not named explicitly.

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?

"Draft-first is preferred" signals when not to use this tool and routes toward the draft workflow, and the confirm_send=true gate is stated up front. It stops short of naming the alternative tool or spelling out the conditions (e.g., irreversible send, no undo) that should decide the choice.

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