Get full email message

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

No annotations are provided, so the description carries the burden. It states the tool fetches full content, which implies a read operation, but does not disclose any side effects, permissions, or limitations. It adds some context (what is included in the content) but lacks details like whether it marks messages as read or requires specific scopes.

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, front-loaded with the action and resource, and includes the key detail about where the ID comes from. No wasted 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?

Given the tool is simple (one parameter, no output schema, no nested objects), the description is complete enough. It explains what the tool does, what the parameter is, and how to obtain it. It could mention return format, but the absence of an output schema and the simplicity of the tool make this acceptable.

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 schema description coverage is 100% (the only parameter messageId is described as 'The Graph message ID.'). The description adds that the ID is 'as returned by list_messages or search_messages', which provides useful context beyond the schema. However, the schema already covers the parameter meaning, so the description adds marginal value.

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 fetches full content of a single message by its Graph message ID, specifying the resource (message) and the action (fetch full content including body, recipients, sender). It also distinguishes from siblings by referencing list_messages or search_messages as sources for the ID.

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: use this tool when you have a message ID from list_messages or search_messages and need full content. It does not explicitly state when not to use it or mention alternatives, but the context is clear enough for an agent to decide.

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