Draft an email

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

Annotations indicate readOnlyHint=false (mutating) and destructiveHint=false. The description adds value by disclosing recipient validation, the fact that it does not send, and optional CRM linking. This provides behavioral insight beyond annotations, though it could mention whether drafts are overwritten or appended.

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 sentences, front-loaded with the core action, no redundant words. Every sentence provides essential information without fluff.

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?

The tool has 6 parameters, no output schema, and minimal annotations. The description covers core purpose and key constraints but omits details like return behavior, error handling for invalid recipients, or what happens to existing drafts. It is adequate but has clear gaps in completeness.

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 33% with descriptions for 'to' and 'company' in the schema. The description adds mention of recipients being validated (relating to 'to') and optional CRM linking (relating to 'company'), but does not explain 'cc', 'body', 'subject', or 'project'. Given low coverage, the description insufficiently compensates.

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 it composes and saves an email draft, specifying it does not send and that recipients are validated. It directly addresses the verb 'draft' and distinguishes from siblings like 'mark_email_sent' or 'list_mail' by emphasizing the draft-only behavior.

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 says the tool does not send and explains the reason (no mail connector), implying it is for draft creation only. However, it does not explicitly contrast with sibling tools like 'mark_email_sent' for sending, which would strengthen guidance.

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