update-mail-message

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

Annotations already indicate destructiveHint=true and readOnlyHint=false, marking this as a write operation. The description adds context about which properties can be updated (e.g., isRead, flag, categories, importance) but does not disclose extra behavioral traits like side effects, required permissions, or rate limits. It does not contradict annotations.

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 sentence that front-loads the purpose and includes specific examples. Every part adds value; there is no waste. It is appropriately short and clear.

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?

Given the tool's complexity (5 parameters, nested objects, no output schema), the description covers the main use cases (updating message properties) adequately. It does not explain return values, but annotations and sibling tools provide context. Minor gaps: no mention of handling drafts vs sent messages, or partial updates.

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 80%, so most parameters are already documented. The description adds meaning by listing example updates (mark read, flag, change categories, etc.), which maps to some body properties. However, not all parameters (like confirm, includeHeaders) are covered in the description, and the body schema includes properties not mentioned (e.g., attachments, toRecipients).

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 verb (update) and the resource (existing Outlook email message), and provides specific examples like mark read/unread, flag, change categories, importance, edit draft's subject, body, or recipients. This distinguishes it from siblings such as send-mail, delete-mail-message, or create-draft-email.

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 provides examples of when to use the tool (update properties) but lacks explicit guidance on when not to use it or alternatives. For instance, it does not contrast with send-mail for sending or delete-mail-message for deletion. Usage is implied but not explicit.

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