start

// WHEN AI AGENTS USE THIS TOOL

AI agents invoke start to trigger processes or run actions in Browserbase. 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 START

start 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.

browserbase.yaml

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

See the full Browserbase policy for all 6 tools.

// DETAILS

Tool Name start

Category Execute

MCP Server Browserbase MCP Server

Risk Level High

// MORE BROWSERBASE TOOLS

Execute act Execute end Execute navigate Read extract Read observe

// WHAT CAN GO WRONG

Agents calling execute-class tools like start 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

start is one of the high-risk operations in Browserbase. 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 start tool do? +

Create or reuse a Browserbase session. It is categorised as a Execute tool in the Browserbase MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on start? +

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

What risk level is start? +

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

Can I rate-limit start? +

Yes. Add a rate_limit block to the start 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 start completely? +

Set action: deny in the Intercept policy for start. 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 start? +

start is provided by the Browserbase MCP server (browserbase). Intercept sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policies on Browserbase