Open WebUI MCP Server

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

With no annotations provided, the description carries full burden for behavioral disclosure. It mentions 'ADMIN ONLY' (a permission requirement) but doesn't cover other critical aspects: whether the update is reversible, what happens to existing group members during the update, rate limits, error conditions, or what the output contains. For a mutation tool with zero annotation coverage, this is insufficient.

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 extremely concise—two short sentences with zero wasted words. It's front-loaded with the core purpose and includes a critical permission note. Every word earns its place, making it highly efficient.

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?

Given the tool's complexity (a mutation with 3 parameters in a nested object, no annotations, but with an output schema), the description is minimally adequate. The output schema existence means return values don't need explanation, but the description lacks details on permissions, behavioral traits, and parameter nuances. It covers the basics but leaves significant gaps for an admin-only mutation tool.

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 0%, so the description must compensate. It mentions updating 'name or description,' which aligns with two of the three parameters in the nested GroupUpdateParam object (group_id, name, description). However, it doesn't explain the group_id parameter at all or clarify that name and description are optional (nullable). The description adds some value but doesn't fully compensate for the schema's lack of descriptions.

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 ('Update') and resource ('group's name or description'), making the purpose specific and understandable. However, it doesn't differentiate this tool from other update tools like update_user_role or update_channel, which would require a 5.

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 no guidance on when to use this tool versus alternatives like update_user_role or create_group. The 'ADMIN ONLY' note is a permission constraint, not usage guidance. There's no mention of prerequisites, when-not-to-use scenarios, or comparisons with sibling tools.

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