Set climate mode

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

Annotations already declare idempotent=true, destructive=false, and openWorld=false, so safety is covered. The description adds useful context beyond annotations: it discloses the exact service call, the JSON payload shape, the HTTP transport, and the return value (changed states) — though the return detail is partly redundant given an output schema exists.

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 with the action, followed by the underlying call, then clearly labeled Use when / Not for / Returns lines. Tight and zero waste.

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?

For a two-param, fully-specified mutation, the definition covers purpose, routing to the correct sibling, transport/payload, and return behavior. Nothing needed to invoke it correctly is missing, even though some of the return information overlaps the output schema.

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%, so both parameters (entity_id, hvac_mode) are already fully documented in the schema, including the mode list. The description restates the mode values but adds no syntax, format, or edge-case detail beyond what the schema provides; baseline 3 applies.

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 (Set) and resource (a climate entity's heating/cooling mode), and names the exact underlying call `climate.set_hvac_mode`. An agent can distinguish it from siblings like services_set_cover_position or entities_set_value without opening any 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?

Explicitly gives when to use (switching a thermostat between heat/cool/auto/off/fan_only/dry) and an explicit not-for clause that routes temperature changes to `entities_set_value`. This is the full when/when-not/alternative pattern.

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