openwebui_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. It discloses that base64-encoded content is required for MCP stdio transport and implies a returned file ID for downstream use. However, it omits details like persistence, overwrite behavior, or potential errors, which for a simple upload tool is understandable but leaves some transparency gaps.

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 two concise sentences. The first states the core purpose, and the second provides a critical requirement and a clear next-step reference. Every sentence earns its place with no redundant information.

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 simple upload tool with three parameters and no output schema, the description covers the main action, a key requirement, and the intended follow-up workflow. It does not mention size limits, authentication, or error conditions, but given the low complexity, it is sufficiently complete for an agent to invoke correctly.

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 description coverage is 100%, so all parameters are already documented in the input schema. The description adds context about the base64 requirement for MCP stdio transport, which slightly enhances understanding, but this does not significantly elevate the semantic value beyond what the schema provides. Thus, a baseline score of 3 is appropriate.

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' and resource 'file to Open WebUI', distinguishing it from sibling file-related tools like list_files, delete_file, and add_file_to_knowledge. The explicit mention of using the returned file ID with add_file_to_knowledge further clarifies its distinct role in the workflow.

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 clear context on when to use this tool: it handles uploading with base64-encoded content required for MCP stdio transport, and it directs the user to a follow-up action (add_file_to_knowledge). It lacks explicit exclusions or direct comparison to alternatives, but the workflow guidance is strong enough for a 4.

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