imap_upload_file

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

With no annotations provided, the description carries the full burden, and it does so well. It discloses both the max upload size (26214400 bytes) and the auto-deletion behavior (after 86400000 ms), including configurable environment variables. It also states the side effect of returning a path for later use, making the tool's behavior and lifecycle transparent.

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 compact and front-loaded: the main action and purpose appear in the first sentence, workflow in the second, and limits/lifecycle in the third. Every sentence conveys a needed fact without fluff or repetition.

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 tool with no annotations and no output schema, this description is complete enough for an agent to call it correctly and integrate it into the email-sending workflow. It explains purpose, when to use it, the next step, size constraints, and auto-cleanup behavior; nothing essential is missing.

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 already documents all three parameters: filename, base64-encoded content, and MIME type, so schema coverage is 100%. The description adds no parameter-specific detail beyond the general purpose, so the baseline score of 3 is appropriate: the schema handles parameter semantics, and the description adds minimal unique param guidance.

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 'Upload a file to the attachment root' and the resource/use case: 'return a path for imap_preview_send_email attachments.' It explains what the tool does and why it exists, distinguishing it from siblings by positioning it as an attachment-staging step rather than a send or preview operation.

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?

It gives an explicit workflow: upload, preview, then 'use imap_confirm_send only after explicit user confirmation.' It also provides the rationale for using this path ('avoids putting large attachment bytes in the context window'), which clearly signals when this tool is appropriate.

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