Low Risk

purchase

Purchase pipeline check credits. Returns a Stripe Checkout URL that the user must open in a browser to complete payment. The AI cannot complete the payment. Tell the user to open the URL in their browser, complete the Stripe checkout, and then confirm they've paid. Credits are added to the accou...

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

AI agents call purchase to retrieve information from Unphurl without modifying any data. This is common in research, monitoring, and reporting workflows where the agent needs context before taking action. Because read operations don't change state, they are generally safe to allow without restrictions -- but you may still want rate limits to control API costs.

Even though purchase only reads data, uncontrolled read access can leak sensitive information or rack up API costs. An agent caught in a retry loop could make thousands of calls per minute. A rate limit gives you a safety net without blocking legitimate use.

Read-only tools are safe to allow by default. No rate limit needed unless you want to control costs.

unphurl.yaml
tools:
  purchase:
    rules:
      - action: allow

See the full Unphurl policy for all 13 tools.

Tool Name purchase
Category Read
MCP Server Unphurl MCP Server
Risk Level Low

View all 13 tools →

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

Browse the full MCP Attack Database →

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

What does the purchase tool do? +

Purchase pipeline check credits. Returns a Stripe Checkout URL that the user must open in a browser to complete payment. The AI cannot complete the payment. Tell the user to open the URL in their browser, complete the Stripe checkout, and then confirm they've paid. Credits are added to the account automatically once Stripe confirms payment. After purchase, use get_balance to verify credits have been added.. It is categorised as a Read tool in the Unphurl MCP Server, which means it retrieves data without modifying state.

How do I enforce a policy on purchase? +

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

What risk level is purchase? +

purchase is a Read tool with low risk. Read-only tools are generally safe to allow by default.

Can I rate-limit purchase? +

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

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

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

Enforce policies on Unphurl

Open source. One binary. Zero dependencies.

npx -y @policylayer/intercept
github.com/policylayer/intercept →
// GET IN TOUCH

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