Home Assistant MCP Server

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List services

list_services

Read-onlyIdempotent

Query Home Assistant service signatures to discover available domains and service names, then retrieve parameter schemas and full details for a specific domain or service.

Instructions

Expose registered service signatures. With no arguments returns each domain and its service names. With a domain returns descriptions and parameter schemas for its services. With domain and service returns that one service in full detail.

Tool call template

This tool declares no required parameters. Add optional parameters from the input schema as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {},
    "name": "list_services"
  }
}

Input Schema

Name	Required	Description	Default
`domain`	No	Service domain, for example 'light' or 'climate'.
`service`	No	Single service name within the domain, for example 'turn_on'.

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.2.1Nov 5, 2026

TDQS

A4.2/5.0

Behavior4/5

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

The annotations already establish that this is a safe, read-only, idempotent, non-destructive, closed-world operation. Beyond that, the description usefully discloses the progressive return behavior: no arguments returns domain/service names, a domain returns descriptions and parameter schemas, and a specific service returns full detail. It does not cover invalid input behavior, which is a minor gap for a simple read-only lookup.

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?

Three sentences map directly to the three invocation modes, with no wasted wording. The most important broad behavior is front-loaded and the escalation to more specific queries follows logically.

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 read-only lookup with no output schema, the description is nearly complete because it explains what is returned at each argument level. A small gap remains around edge cases, such as what happens when service is supplied without domain or when a domain/service is invalid.

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

Parameters4/5

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

Schema coverage is 100%, so the schema already documents both optional parameters with examples. The description adds meaningful semantics by explaining how the parameters combine: no arguments for a broad listing, domain for service-level detail, and domain plus service for full detail on one service.

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 states a specific resource and action: exposing registered service signatures. It clearly distinguishes the three result granularities (all domains, a domain, and a single service), so an agent understands what the tool does without opening the schema.

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

Usage Guidelines3/5

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

The description explains how to invoke the tool at different levels of detail, which is useful implied usage guidance. However, it does not explicitly say when to use this tool versus siblings such as get_entity_details, list_registry, or search_entities, and it provides no exclusions or prerequisites.

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