Press Key

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

Beyond the annotations, the description discloses supported key categories, the no-selector fallback, and the exact minimal return shape (tag plus id/name/type/aria-label). The return caveat is valuable because no output schema exists, and it does not contradict the annotations.

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?

Three sentences, front-loaded with the primary action, then capabilities, then the return limitation and alternative. Every sentence earns its place, and there is no filler or redundancy with the schema.

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?

With no output schema, the description adequately explains what the tool returns and directs the agent to query_elements for richer data. All four parameters are fully documented in the schema, and the key decision (selector vs focused element) is called out, so the agent can 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?

Schema coverage is 100%, so the baseline is 3. The description adds meaning for selector behavior ('focused element when no selector is given') and reinforces valid key values, which goes slightly beyond what the schema alone states. It does not add detail for exact or tab_id, but the schema already covers those.

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 opens with a specific verb and resource ('Dispatch a key press to an element'), then clarifies the fallback target ('focused element') and supported key forms ('named keys ... and single printable characters'). This clearly separates it from mouse-interaction siblings like click and fill.

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 states when the focused element is used ('when no selector is given') and points to query_elements as the alternative when a full element picture is needed. It does not enumerate exclusions relative to click/fill/select_option, but the guidance is clear enough for correct invocation.

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