keycloak-mcp-server

assign-role-to-user

Assign a specified role to a user in Keycloak. Provide realm, user ID, and role name; optionally include client ID to assign a client role.

Instructions

Assign a realm role, or a client role when clientId is given, to a user

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": {
      "realm": "<realm>",
      "userId": "<userId>",
      "roleName": "<roleName>"
    },
    "name": "assign-role-to-user"
  }
}

Input Schema

Name	Required	Description
`realm`	Yes	Realm name
`userId`	Yes	User ID
`clientId`	No	Client ID to resolve roleName as a client role. Omit for a realm role
`roleName`	Yes	Role name

Schema Changelog

Changes observed during successful MCP inspections.

First observedv2.0.0Aug 14, 2026

TDQS

A4/5.0

Behavior3/5

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

No annotations are provided, so the description must carry the burden of behavioral disclosure. It does add context about the dual realm/client role behavior, but it does not mention permissions, idempotency, what happens if the role already exists, or the response format. This is a clear but basic mutation tool; more transparency would be valuable.

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?

The description is a single sentence of about 15 words, front-loaded with the action and resource. It is optimally concise with no filler or redundant detail.

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 4-parameter assignment tool with no output schema, the description covers the essential behavior and the one conditional parameter (clientId). It could mention response details or error conditions, but given the low complexity, it is largely complete.

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 coverage is 100%, so per the rubric the baseline is 3. The description adds no new parameter semantics beyond what the schema already provides, and the clientId explanation mirrors the schema description.

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: 'Assign a realm role, or a client role when clientId is given, to a user'. It uses a specific verb ('assign') and identifies the resource (role) and recipient (user). It also distinguishes between realm and client roles, which differentiates it from sibling tools like remove-role-from-user or assign-role-to-group.

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 provides clear usage context by specifying that clientId is used for client roles, otherwise a realm role is assigned. However, it does not explicitly mention alternatives or 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.

Deploy Server