Get host OS info

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

Annotations already declare readOnly/idempotent/non-destructive, so the safety profile is covered; the description adds real behavioural context by disclosing the underlying GET /host/info call and the concrete auth failure (SUPERVISOR_TOKEN not set, requires running as an HA add-on). It does not mention rate limits, but for a read-only info call that is minor.

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?

Front-loaded purpose sentence followed by clearly labelled Use when / Not for / Returns / Errors blocks that are easy to scan. The Returns block is somewhat redundant given an output schema exists, which keeps this from a 5.

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?

With an output schema present and annotations covering the safety profile, the description only needs to add selection guidance and failure modes — and it does both, including the exact error payload. Nothing needed to call it correctly is missing.

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?

The tool takes zero parameters, so there is nothing to document and the baseline of 4 applies. The description correctly adds no parameter prose, avoiding noise.

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 and resource ('Get info about the host operating system') and names the exact sibling it must not be confused with (Core, Supervisor, supervisor_get_supervisor_info). An agent can select this tool without opening any other schema.

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?

Explicit 'Use when' clause scopes it to underlying OS/hardware rather than Core or Supervisor, and the 'Not for' clause routes Supervisor's own version to supervisor_get_supervisor_info. Both the trigger and the alternative are named.

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