upload_file

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

Even though annotations only say readOnlyHint=false and destructiveHint=false, the description adds substantial behavioral context: temporary server-side storage, auto-deletion after 1 hour, deletion via release_file, and a precise return mapping. This goes well beyond what annotations provide and does not contradict them.

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 and front-loaded with the purpose, followed by concise Args and Returns sections. Every sentence contributes useful information, with no filler or repetition of schema details.

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?

With no output schema, the description compensates by explicitly listing the return keys (session_id, file_path, message) and their meanings. It covers input formats, temporary lifecycle, cross-tool usage, and cleanup, making the tool fully usable from the description alone.

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 has 0% description coverage, but the description fully compensates. It explains that file_content can be base64-encoded bytes or an HTTP/HTTPS URL, and that filename is a hint for determining the file extension (e.g., 'data.xlsx'). This adds clear semantics beyond the bare parameter names.

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 opens with a clear verb and object: 'Upload a file for server-side processing.' It distinguishes this tool from its siblings (download_file, release_file, multi_file) by explicitly stating it accepts a base64 string or HTTP/HTTPS URL and returns a session_id and file_path for use with other tools.

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 clearly implies when to use the tool: it is the entry point to get a session_id and file_path that 'can be used with any other tool.' It also mentions lifecycle details like 1-hour auto-deletion and release_file. However, it does not explicitly name alternative tools or state when not to use this tool, so it stops short of a 5.

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