openwebui-mcp-server

openwebui_add_file_to_knowledge

Add an uploaded file to a knowledge base for RAG retrieval. Use the file ID from the upload response to link it to a specific knowledge base.

Instructions

Add an uploaded file to a knowledge base for RAG retrieval. The file must already be uploaded via openwebui_upload_file. Get the file ID from the upload response.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "knowledge_id": "<knowledge_id>",
      "file_id": "<file_id>"
    },
    "name": "openwebui_add_file_to_knowledge"
  }
}

Input Schema

Name	Required	Description	Default
`file_id`	Yes	File ID (from openwebui_upload_file response)
`knowledge_id`	Yes	Knowledge base ID

Schema Changelog

Changes observed during successful MCP inspections.

First observedv1.0.2Aug 10, 2026

TDQS

A3.8/5.0

Behavior2/5

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

With no annotations, the description carries the full burden. It mentions the prerequisite but does not disclose any side effects, permissions, idempotency, or error behavior. Since this is a mutation tool, the lack of such detail is a significant gap.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Two sentences with no fluff. Each sentence earns its place: one states the purpose, the other states the prerequisite and parameter source.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a simple 2-parameter add operation, the description covers the essential prerequisite and purpose. It lacks details about return values or failure modes, but the schema and simplicity of the tool make this acceptable.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, with both parameters already described. The description adds marginal value by re-emphasizing where to get the file ID, but does not meaningfully extend the schema semantics.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the action ('Add an uploaded file to a knowledge base') and the purpose ('for RAG retrieval'). It includes the prerequisite that the file must already be uploaded, which distinguishes it from upload and removal sibling tools.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description gives clear context by specifying the prerequisite ('The file must already be uploaded via openwebui_upload_file') and how to get the file ID. It does not explicitly mention alternatives or when not to use, but the context is clear enough for an agent.

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