gmail_update_draft

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It clearly warns that ANY ATTACHMENT NOT RE-SPECIFIED IS DROPPED, which is a critical side-effect. It also explains how to retain attachments via messageId/attachmentId. This is exemplary transparency for a mutating operation.

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 two sentences with no filler. It leads with the core purpose, then immediately states the critical caveat about attachments, and finishes with a concrete workaround. Every sentence earns its place, and the structure is ideal for quick agent parsing.

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 mutation tool with 8 parameters, no annotations, and no output schema, the description covers the essential behavioral hazard (attachment loss) and provides a practical usage pattern. It does not describe the return value or mention prerequisites like the draft existing, but given the clarity of the operation and the schema's parameter descriptions, it is reasonably complete. A short note on the response would push it to 5.

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 low (38%), so the description must compensate. It adds significant meaning to the attachments parameter by explaining both the file-path variant and the re-attach variant, and it clarifies that messageId comes from gmail_get_draft. It does not elaborate on other parameters, but the schema already provides descriptions for to, body, and account, and the description's guidance on attachments covers the most complex parameter.

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 states a specific verb ('Replace') and a clear resource ('the contents of a Gmail draft'). It distinguishes itself from siblings like gmail_create_draft, gmail_get_draft, and gmail_delete_draft by emphasizing it is a full replacement, not a partial update. An agent can immediately understand what this tool does without ambiguity.

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?

The description explicitly notes that Gmail has no partial draft update, implying this tool should be used only when a full replacement is intended. It also provides a concrete usage pattern for preserving attachments by referencing gmail_get_draft. It does not explicitly contrast with alternatives like gmail_create_draft, but the context is clear enough for most cases.

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