upload_file

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

Without annotations, the description carries the full burden of disclosing behavioral traits. It mentions Base64 encoding and server-side decoding/storage, but omits critical details like file size limits, allowed MIME types, idempotency, permissions, or error handling.

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?

Two concise sentences that front-load the core purpose and include a technical detail (Base64 encoding). Every word earns its place with no redundancy.

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 fails to mention the return value or output (e.g., file ID, URL). Given no output schema, this is a significant gap. Also missing are potential errors or side effects, making the tool contextually incomplete for safe agent use.

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?

Input schema has 100% coverage, so the baseline is 3. The description reinforces that content_base64 is Base64-encoded, but adds no additional meaning beyond the schema for other parameters. The extra clarification is minor.

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 uploads a file attachment and associates it with a message, specifying the encoding and storage process. It distinguishes itself from sibling tools like 'download_file' by the upload action.

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 (e.g., when to upload vs. when to download). There is no mention of prerequisites, constraints, or context that would help an agent choose this tool.

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