Fills input elements using a CSS selector, enabling secure form automation in guarded browsing sessions when write mode is active.
입력 요소에 값을 채운다. 읽기 전용 모드(기본)에서는 거절된다.
| Name | Required | Description | Default |
|---|---|---|---|
| value | Yes | 입력할 값 | |
| selector | Yes | 입력 요소의 CSS 셀렉터 |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations declare readOnlyHint=false, confirming it's a write operation. The description adds valuable context that calls are rejected in default read-only mode, which is not present in annotations. This goes beyond what structured fields provide.
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 concise sentences, front-loaded with the core action and immediately followed by the critical rejection condition. No wasted words.
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 fill tool with two fully-documented parameters, the description covers the main behavior and the key constraint (read-only rejection). It could mention that the selector must reference an interactive input, but this is minor and largely implied.
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 both parameters (selector and value) are already documented with descriptions. The tool description does not add extra semantic detail beyond what the schema provides, maintaining the baseline score.
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 ('fill') and resource ('input element') with a clear action. Distinguishes from siblings like browser_click and browser_get_text by targeting input elements specifically.
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?
Implied usage: it's clear this tool is for populating form fields, and the read-only mode rejection hints at when it won't work. However, it does not explicitly name alternatives or conditions for choosing it over other interaction tools.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.