// MCP TOOL REFERENCE

browser_execute_script

Execute JavaScript code in the context of the current page. Returns the result.

Accepts freeform code/query input (code)

Part of the Browser MCP server. Enforce policies on this tool with Intercept, the open-source MCP proxy.

// WHEN AI AGENTS USE THIS TOOL

AI agents invoke browser_execute_script to trigger processes or run actions in Browser. Execute operations can have side effects beyond the immediate call -- triggering builds, sending notifications, or starting workflows. Rate limits and argument validation are essential to prevent runaway execution.

// WHY ENFORCE A POLICY ON BROWSER_EXECUTE_SCRIPT

browser_execute_script can trigger processes with real-world consequences. An uncontrolled agent might start dozens of builds, send mass notifications, or kick off expensive compute jobs. Intercept enforces rate limits and validates arguments to keep execution within safe bounds.

// RECOMMENDED POLICY

Execute tools trigger processes. Rate-limit and validate arguments to prevent unintended side effects.

io-github-agent360dk-browser-mcp.yaml

tools:
  browser_execute_script:
    rules:
      - action: allow
        rate_limit:
          max: 10
          window: 60
        validate:
          required_args: true

See the full Browser policy for all 29 tools.

// DETAILS

Tool Name browser_execute_script

Category Execute

MCP Server Browser MCP Server

Risk Level High

// MORE BROWSER TOOLS

Execute browser_hover Execute browser_navigate Execute browser_wait Execute browser_wait_for_network Write browser_click Write browser_close_tab Write browser_fill Write browser_handle_dialog

View all 29 tools →

// WHAT CAN GO WRONG

Agents calling execute-class tools like browser_execute_script have been implicated in these attack patterns. Read the full case and prevention policy for each:

Browse the full MCP Attack Database →

// OTHER EXECUTE TOOLS ACROSS MCP SERVERS

Other tools in the Execute risk category across the catalogue. The same policy patterns (rate-limit, validate) apply to each.

Agent Passport System — Cryptographic Identity for AI Agents commerce_preflight Agent Passport System — Cryptographic Identity for AI Agents execute_with_context Agent Passport System — Cryptographic Identity for AI Agents gateway_execute_approval Agent Passport System — Cryptographic Identity for AI Agents governance_360 Agent Passport System — Cryptographic Identity for AI Agents parse_governance_block_html AgentClear — API Marketplace for AI Agents call_service

// IN CONTEXT OF HIGH RISK

browser_execute_script is one of the high-risk operations in Browser. For the full severity-focused view — only the high-risk tools with their recommended policies — see the breakdown for this server, or browse all high-risk tools across every MCP server.

// RELATED READING

// FAQ

What does the browser_execute_script tool do? +

Execute JavaScript code in the context of the current page. Returns the result.. It is categorised as a Execute tool in the Browser MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on browser_execute_script? +

Add a rule in your Intercept YAML policy under the tools section for browser_execute_script. You can allow, deny, rate-limit, or validate arguments. Then run Intercept as a proxy in front of the Browser MCP server.

What risk level is browser_execute_script? +

browser_execute_script is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit browser_execute_script? +

Yes. Add a rate_limit block to the browser_execute_script rule in your Intercept 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.

How do I block browser_execute_script completely? +

Set action: deny in the Intercept policy for browser_execute_script. 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.

What MCP server provides browser_execute_script? +

browser_execute_script is provided by the Browser MCP server (@agent360/browser-mcp). Intercept sits as a proxy in front of this server to enforce policies before tool calls reach the server.

browser_execute_script

Enforce policies on Browser