forward-mail-message

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

Annotations indicate destructiveHint=true, so write behavior is expected. The description adds that the message is saved in the Sent Items folder, mentions HTTP 400 error conditions, and notes that MIME must be base64 encoded. This provides good behavioral context beyond the 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 well-structured with bullet points for each format and a separate tip. It is not overly verbose; each sentence adds value. Could be slightly more concise, but overall effective.

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 description covers main behavioral aspects (format options, error conditions, sent storage) but is missing details about the response (no output schema). The agent may need to know what the API returns upon success or failure. Given complexity, a bit more completeness would be ideal.

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 75%, baseline 3. The description adds significant meaning beyond the schema: it clarifies mutual exclusivity of comment/body and toRecipients/parameter, and explains that MIME format requires base64 encoding. This helps the agent correctly construct the request.

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 forwards a message using JSON or MIME format. It distinguishes from sibling create-forward-draft by noting that this method saves to Sent Items immediately, while a draft can be created and sent later. The tip reinforces the purpose by advising against manual reconstruction.

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 guidance on when to use this tool versus creating a draft ('Alternatively, create a draft to forward a message, and send it later'). It also warns against specifying both comment and body, or both toRecipients in two places. However, it does not explicitly guide choice between JSON and MIME formats.

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