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

Annotations already mark this as destructive and not read-only. The description adds useful nuance by saying only mutable fields are saved and that sender overrides are validated, but it does not explain side effects, whether fields are cleared when omitted, or other consequences beyond the annotation hints.

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, front-loaded sentence with no filler. It efficiently communicates the core update operation and the secondary override behavior without wasting words.

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?

With no output schema and no parameter documentation, the description leaves out critical invocation details: which fields can be edited, what the override field is called, and what the response contains. The tool's destructive and idempotent nature is covered by annotations, but the operational payload contract is missing.

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%, and the schema only exposes id, request_id, and idempotency_key. The description mentions 'mutable candidate email draft fields' and a 'sender override' but does not name or explain the payload keys, making it difficult for an agent to construct a correct request. It provides only high-level intent, not operational parameter meaning.

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 tool updates/saves mutable candidate email draft fields and can set or clear a validated sender override. This distinguishes it from siblings like email_drafts_read, email_drafts_send, and email_drafts_discard, even without naming them.

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 implies usage: it is for editing an existing draft, not for sending, discarding, listing, or reading. However, it does not explicitly state when to prefer this over alternatives or mention exclusions, so guidance remains implicit rather than explicit.

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