set_temperature

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

Annotations already declare destructive=true, openWorldHint=true, and non-idempotent. The description goes beyond them by disclosing the partial-update behavior (omitted setpoints are kept) and the exact authorization requirements for hosted vs local use, which is genuinely useful context for a mutation tool.

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?

Three tight sentences: purpose and scope first, then parameter behavior, then permissions. No filler, and the most important constraint (the 1–24 hour hold) is front-loaded.

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 write tool, the description pairs annotations (destructive, open-world) with authorization requirements, expiry semantics, and partial-update behavior. No output schema exists, but that is acceptable for a setter; the only gap is the absence of alternative-tool routing.

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 only 20% (just thermostat_id), so the description must compensate, and it does: it explains that heat/cool may be supplied singly or together, that units must be explicit F/C, and that omitted setpoints persist. It still does not fully enumerate all five parameters, so it is not exhaustive.

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 plus a scoping constraint ('Set a 1–24 hour temperature hold'), which clearly separates it from set_hvac_mode and resume_schedule. It never names a sibling explicitly, so it falls short of the 'distinguishes from siblings' bar for a 5.

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?

Gives concrete operating conditions ('Supply heat, cool, or both with explicit F/C units. Keeps any omitted setpoint') and prerequisites (account write permission, client write scope, or --allow-writes locally). It does not state when NOT to use this versus resume_schedule or set_hvac_mode, so no exclusions or alternative routing.

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