select_profile

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

No annotations are provided, so the description carries the full burden. It adds that the switch 'takes effect immediately,' which is a useful side-effect detail. However, it does not mention persistence, error handling, or any impact on other profiles, leaving some transparency gaps.

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?

The description is two sentences, with the first sentence immediately stating the action and target. Every word earns its place; there is no fluff or redundancy.

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 simple one-parameter tool, the description covers the core purpose, the prerequisite step, and the immediate effect. An output schema exists to document return values, so the description need not repeat those. Minor gaps like out-of-range behavior are not critical for this simple 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 schema already explains 'profile_index' as the 0-based index and points to list_profiles. The tool description repeats this guidance ('Use list_profiles first') but does not add new semantic information beyond what the schema provides, so baseline 3 is appropriate.

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?

The description uses a specific verb ('Switch') plus a clear resource ('the active Karabiner-Elements profile'). It distinguishes from sibling tools like list_profiles, which lists profiles, and rule-editing tools, which operate on rules rather than profiles.

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?

It explicitly instructs to 'Use list_profiles first to see available profiles and their indices,' giving a clear prerequisite step. It does not discuss exclusions or alternatives beyond this, but the guidance is specific and actionable.

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