Press a key

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

Annotations already declare destructiveHint=true and non-idempotent, so the agent knows a keypress can trigger irreversible effects. The description adds nothing behavioral beyond that — no warning that a key can fire destructive actions, no statement about focus/target window, and no note on repeat or timing. With annotations present, a small amount of added context is expected but nearly absent here.

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 compact sentences with no padding; the key-format examples lead and the macOS note follows. Slightly awkward as an opening fragment, but 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?

For a five-parameter, zero-schema-coverage, no-output-schema tool, the description covers only the primary parameter and one modifier. Modifier keys and the consequences of a destructive keypress are left unstated, which is thinner than this tool's complexity warrants.

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 0% across five parameters, so the description must carry the load. It does explain the `key` value format well (literals like "Enter", "ArrowLeft", "=", plus egui names like "Plus") and clarifies that `cmd` maps to Cmd on macOS, but `alt`, `ctrl`, and `shift` are never addressed and no combination semantics are given.

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 conveys that this simulates a keypress on the canvas and gives concrete key examples ("A", "Enter", "ArrowLeft", "Plus"), so the resource is identifiable. But it is a noun-phrase fragment with no verb and no differentiation from the sibling `type_text`, which is the obvious confusion point for an agent choosing between keyboard tools.

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?

There is no statement of when to use this tool versus `type_text`, `pointer`, or `run_command`, and no prerequisites or exclusions. The examples imply 'single key/shortcut' usage but that inference is left entirely to the agent.

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