Press Key

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

The description discloses that a target, if provided, is clicked or focused first — a side effect not obvious from the annotations. It also states the return value {"ok": true}. Annotations already indicate destructive behavior (destructiveHint=true), so additional warnings are less needed. The description adds useful context beyond the structured fields without contradicting them.

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-organized with separate sections for Args and Use when, making it easy to scan. Every sentence adds value, including examples and return type. 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?

Despite having 9 parameters, the description covers the key aspects: what it does, how to specify targets, examples of key syntax, and the behavior when no target is given. Combined with the fully described schema and output schema, the description is complete enough for an agent to select and invoke the tool 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?

Although schema coverage is 100%, the description adds meaning by explaining the key syntax with examples and clarifying the behavior when no target is given ('key goes to whatever currently has focus'). It also notes that elementId is preferred over selector or coordinates, but this is partially echoed in the schema. Overall, the description enhances understanding of parameter usage beyond the raw 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 clearly states the tool's function: 'Sends a key or chord to the focused element or page' with concrete examples like 'Enter', 'Escape', 'Control+A'. This specifies the verb (sends), resource (key or chord to element/page), and distinguishes from siblings such as typ_text (which inputs text) or click (which clicks).

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 provides explicit 'Use when' examples, such as 'press Enter to submit the search' and 'select all text in this field', indicating appropriate scenarios. It also explains how targeting works ('If a target is given, it is clicked/focused first'), but does not explicitly mention when not to use the tool or name alternative tools, so it falls short of a 5.

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