Replace the contents of an editable UI element. If not directly editable, focus it, select all, and type the new text.
Replace the contents of an editable ui_tree element. Falls back to focusing it, select-all and typing when the widget isn't directly editable.
| Name | Required | Description | Default |
|---|---|---|---|
| id | Yes | ||
| text | Yes | ||
| screenshot_after | No |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full behavioral burden. It usefully discloses the fallback strategy (focus, select-all, typing) which implies existing content is overwritten, but it omits return behavior, error cases when the element isn't editable at all, and side effects like focus stealing.
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 tight sentences with the primary action front-loaded and the fallback detail second. No wasted words, though the fallback clause is slightly run-on.
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?
A mutation tool with no annotations, no output schema, and 0% parameter coverage leaves meaningful gaps: 'screenshot_after' is unexplained and return/error behavior is unstated. The description covers the core action but not enough for an agent to call it confidently in all cases.
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 three parameters. The description only obliquely covers 'id' (the ui_tree element) and 'text' (the contents), and says nothing at all about 'screenshot_after', which is entirely undocumented in both description and 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?
States a specific verb and resource: 'Replace the contents of an editable ui_tree element.' The verb 'replace' (versus the sibling type_text's append/type behavior) gives the agent a usable distinction, though no sibling is named explicitly.
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 implies usage by targeting 'an editable ui_tree element' and describes a fallback path, but it never states when to choose this over type_text, click_element, or key, nor any prerequisite such as the element first being located via ui_tree.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.