graph_send_message

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

No annotations are provided, so the description carries much of the behavioral burden. The top-level description only says 'via Microsoft Graph API', while the schema's own description adds that it uses POST /me/sendMail and requires OAuth2 with Mail.Send. The behavior is available to the agent through the schema, but the description itself adds no extra behavioral insight.

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?

A single imperative sentence with a tightly scoped parenthetical manages to convey both the action and the prime usage condition with zero filler.

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 combination of the compact description and the rich schema (100% param coverage, output schema, nested attachment definition) gives the agent everything needed to invoke it. The only thing absent from the description/schema is an explicit comparison to smtp_send_message, but the attention-grabbing definition is sufficient.

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?

The description does not mention any of the 12 parameters, but the schema provides 100% description coverage for every field, so the baseline of 3 applies. The schema fully describes recipients, subject, bodies, attachments, and threading fields.

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?

States a specific verb and target (send email via Microsoft Graph API) and immediately gives the critical use-case context (required when SMTP is blocked for personal hotmail/outlook.com accounts). This clearly separates it from sibling SMTP/EWS/IMAP senders.

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 parenthetical gives a clear condition for choosing this tool: personal hotmail/outlook.com accounts where SMTP is blocked. It does not explicitly name the preferred alternative (e.g., smtp_send_message) or describe when NOT to use it, but the context is clear enough.

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