keyboard_input

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

There are no annotations, so the description carries the full transparency burden. It discloses a non-obvious side effect: the tool automatically resumes if stopped and restores the pause state afterward. It also communicates the one-to-four-key cap and the supported action types. It does not cover failure modes, but an output schema is present.

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?

Two concise sentences deliver purpose, a key side effect, and the intended use cases. The core scoping fact is front-loaded, and no sentence is wasted.

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 a complete input schema, an output schema, and moderate tool complexity, the description provides enough context for an agent to call the tool correctly. It covers what the tool sends, how many items it accepts, and its side effects on emulator pause state. It does not explicitly route to alternatives, but the use-case sentence gives sufficient selection context.

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 baseline is 3. The description repeats the one-to-four-key limit and PETSCII token idea already present in the keys property, but adds no format, syntax, or operational nuance beyond the schema. The action enum and durationMs are already well described in the input schema.

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 states a specific verb and resource: it sends one to four keys or PETSCII tokens to the C64. It also defines the intended operations (presses, releases, and taps), which clearly differentiates it from sibling input tools like joystick_input.

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 explicitly says 'Use for key presses, releases, and taps', providing clear context for when the tool is appropriate. It does not name alternative tools or state when not to use it, but the intent is unambiguous.

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