Fill multiple form fields in a single call. Supports inputs, textareas, selects, checkboxes, and radios.
AI agents invoke browser_fill_form to trigger actions in YetiBrowser MCP. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call — builds kicked off, notifications sent, workflows started.
This tool interacts with web forms by filling multiple fields at once, triggering browser-side DOM events and potentially auto-submitting forms. It is a browser automation action that modifies web page state and can trigger external operations (e.g., form submissions that create accounts, send messages, or initiate purchases) depending on the form and arguments provided.
From the tool's definition Fill multiple form fields in a single call. Supports inputs, textareas, selects, checkboxes, and radios.
Documented attack patterns abuse exactly the kind of access browser_fill_form gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and YetiBrowser MCP, and nothing reaches the server without passing your rules. This is the rule we recommend for browser_fill_form:
{
"version": "1",
"default": "deny",
"tools": {
"browser_fill_form": {
"limits": [
{
"counter": "browser_fill_form_rate",
"window": "minute",
"max": 10,
"scope": "grant"
}
]
}
}
}browser_fill_form stays usable, but rate-capped — a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.
Free to start. No card required.
Fill multiple form fields in a single call. Supports inputs, textareas, selects, checkboxes, and radios. It is categorised as a Execute tool in the YetiBrowser MCP MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the YetiBrowser MCP server in PolicyLayer and add a rule for browser_fill_form: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches YetiBrowser MCP. Nothing to install.
browser_fill_form is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.
Yes. Add a rate_limit block to the browser_fill_form rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.
Set action: deny in the PolicyLayer policy for browser_fill_form. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.
browser_fill_form is provided by the YetiBrowser MCP server (yetidevworks/yetibrowser-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from YetiBrowser MCP, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
17 YetiBrowser MCP tools catalogued and risk-classified — across an index of 43,000+ MCP servers.