app_press_key

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

With no annotations, the description carries the full burden. It discloses the raw input behavior, all reachable keys including modifiers, and how to combine them. It does not mention potential side effects (e.g., if app loses focus), but for a keyboard input tool, the coverage is good.

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 well-structured with a clear first sentence stating purpose, followed by details on keys and modifiers. While somewhat lengthy, it packs essential information without 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?

Given the single parameter, 100% schema coverage, and no output schema, the description is fully complete. It covers the tool's operation, all valid inputs, and usage examples, leaving no critical gaps.

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 schema already provides 100% coverage with a description and example. The tool description adds significant value by enumerating valid keys and showing modifier combinations, making the parameter semantics clear beyond the schema alone.

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 clearly states 'Send raw keyboard input to the running app window, not tied to any element,' which distinguishes it from sibling tools like app_type (which targets elements). It uses specific verb+resource and effectively sets it apart.

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?

The description implies when to use this tool (keyboard input not tied to an element) and provides extensive examples, but does not explicitly state when not to use it or contrast with alternatives beyond the 'not tied to any element' phrase.

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