update_email_draft

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

Annotations already declare readOnlyHint=false, destructiveHint=false and openWorldHint=false, so the safety profile is largely covered. The description adds one genuinely non-annotated fact — that no email is dispatched — but says nothing about partial-update behavior (what happens to fields not passed, e.g. maxLength limits, whether omitted fields are cleared) or permission needs.

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 filler, with the action and its field scope front-loaded before the reassurance about sending. 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?

An output schema exists, so return values need no explanation, and annotations cover the safety profile. For a mutation tool with 4 parameters and 0% schema coverage, the description is adequate but leaves gaps around draft_id, partial-update semantics, and length limits.

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 carry parameter meaning. It names three of the four parameters (recipient, subject, body) and their role, which is real added value, but omits draft_id entirely and gives no format/length or null/default semantics for the rest.

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 ('Edit a draft') and enumerates the editable fields (recipient, subject, body), which cleanly separates it from get_email_draft and export_email_draft. It stops short of naming any sibling or drawing an explicit boundary with draft_enquiry, so it is clear but not fully differentiated.

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 is sent' implies this is the staging/edit path rather than a send path, which is useful when-to-use context. However, it never states when to prefer this over draft_enquiry or get_email_draft, nor any prerequisites (e.g. draft must already exist), leaving usage only implied.

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