set_key

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

Annotations provide the safety profile (write, not destructive, not idempotent), but the description adds two traits beyond them: 'replacing whatever is there' (overwrite semantics) and 'Staged only' (the change is not live until applied). The staging disclosure is especially valuable for an agent that must later call apply_changes. Nothing here contradicts the annotations.

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, front-loaded with the core purpose before the dial and Multi/Toggle conditions. No filler, though the trailing conditional tips could be grouped more cleanly.

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?

An output schema exists, so return values need no explanation, and all parameters are covered by the schema. The description correctly closes the loop on the staging model and the dial/Multi/Toggle workflows, leaving little an agent needs to call it correctly.

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 the schema already documents all eight parameters, including the slot, device, action, image and title_style formats. The description's only parameter-level addition is that dial actions must 'support Encoder,' which is marginal beyond what the schema states. Baseline 3 applies when the schema does the heavy lifting.

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 ('Place an action on a key or dial') with the scope qualifier 'replacing whatever is there,' so an agent knows this overwrites rather than appends. It distinguishes itself implicitly from add_child by routing Multi/Toggle follow-ups there, but does not explicitly differentiate from update_key or clear_key, so it falls short of full sibling disambiguation.

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 conditional guidance ('For dials use dial<N> with an action that supports Encoder' and 'For a Multi/Toggle Action, set it here, then add_child'), which is genuinely useful workflow context. However it never states when to use set_key versus update_key or clear_key for the ordinary key case, leaving the main selection decision to inference.

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