List Home Assistant users

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

Annotations already declare readOnlyHint=true and openWorldHint=true, so safety is covered. The description adds genuinely useful context beyond that: that system-generated Supervisor users appear in the result and should be left alone, plus the note that username is only present for local logins.

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?

A single front-loaded sentence; the enumerated field list is the bulk of it and earns its place as a substitute for a missing output schema, though it is slightly dense.

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?

There is no output schema, so spelling out the returned fields is exactly the right compensation, and the system-generated-user caveat closes the only real ambiguity for a simple read-only list 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 100% and the single instance_id parameter already documents its refusal behavior, so the description correctly does not repeat it. Baseline 3 applies since the description adds no parameter meaning of its own.

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?

States a specific verb+resource ('List every user on this Home Assistant instance') and enumerates the returned fields, so an agent can distinguish it from siblings like ha_create_user, ha_update_user, or ha_delete_user at a glance.

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?

Usage is implied by the read-only listing purpose, but there is no explicit when-to-use or when-not, and no alternative tool (e.g., a hypothetical single-user getter) is named or excluded.

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