type

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

With no annotations, the description carries the full burden. It usefully discloses that this simulates keystrokes and fires key events rather than setting a value directly — a meaningful behavioral distinction for framework-bound inputs — but it says nothing about failure when the selector matches nothing, focus/scroll behavior, or what the call returns after typing finishes.

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 short sentences, front-loaded with the verb and target, followed by usage and the alternative. No repeated schema info and no wasted clauses.

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 simple three-parameter tool with full schema coverage, no output schema, and no annotations, the description covers purpose, target, mechanism, and sibling routing. The remaining gap is failure behavior and post-condition (e.g., whether text is appended or replaces existing content), which is a minor but real omission.

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 schema already documents selector, text, and delay with ranges and a default. The description adds no parameter-level detail beyond implying keystroke timing semantics; baseline 3 applies when the schema does the heavy lifting.

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 gives a specific verb (type), the target (a focusable element matching a CSS selector), and the mechanism (simulated keystrokes firing key events). It also names the sibling it differs from ('prefer fill'), so an agent can distinguish it from fill/click/press without reading either schema.

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 states the when ('typing into inputs or contenteditable regions') and names an explicit alternative with its selection condition ('For filling a form field in one shot, prefer fill'). It stops short of covering the press sibling, which is the other likely confusion for special keys like Enter or Tab, so the routing guidance is clear but not exhaustive.

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