get-mail-message

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

Annotations already cover read-only, idempotent, and non-destructive behavior. The description adds a useful return-related detail ('including its full body'), but it does not describe default fields, body format, or other response behaviors. It adds some value beyond annotations but is not rich.

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 with no filler or redundant information. It front-loads the action and resource, then immediately adds the key detail about the full body. Every word 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?

For a low-complexity tool with fully documented parameters and strong safety annotations, the description is nearly sufficient for an agent to invoke the call correctly. It could be more complete by explicitly noting how to obtain a messageId or that shared mailbox messages should go through the dedicated shared-mailbox sibling, but those are inferable from the schema and sibling names.

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 input schema provides complete descriptions for both parameters (100% coverage), including the OData $select behavior for 'select' and the role of 'messageId'. The description adds little parameter-level meaning beyond confirming that the full body is included, so the baseline score of 3 is appropriate.

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 action ('Get') and the resource ('a single message'), and adds a meaningful detail that the full body is included. It is clear, but it does not explicitly differentiate from closely related siblings such as get-shared-mailbox-message or list-mail-messages.

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?

No guidance is provided on when to use this tool versus alternatives like list-mail-messages or get-shared-mailbox-message. There is also no mention of prerequisites, such as obtaining a messageId from a list call, or exclusions for shared mailbox scenarios. The usage context is only implicit.

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