Low Risk

list_blocks

Lists all program blocks (OB, FC, FB, DB) for a specific PLC

Single-target operation

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

AI agents call list_blocks to retrieve information from Gangsterke Tia Portal 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 list_blocks 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.

gangsterke-tia-portal.yaml
tools:
  list_blocks:
    rules:
      - action: allow

See the full Gangsterke Tia Portal policy for all 12 tools.

Tool Name list_blocks
Category Read
Risk Level Low

View all 12 tools →

Agents calling read-class tools like list_blocks 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 list_blocks tool do? +

Lists all program blocks (OB, FC, FB, DB) for a specific PLC. It is categorised as a Read tool in the Gangsterke Tia Portal MCP Server, which means it retrieves data without modifying state.

How do I enforce a policy on list_blocks? +

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

What risk level is list_blocks? +

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

Can I rate-limit list_blocks? +

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

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

list_blocks is provided by the Gangsterke Tia Portal MCP server (@iflow-mcp/gangsterke-tia-portal-mcp-server). Intercept sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Let agents act without letting them run wild.

Deterministic policy on every MCP tool call. Per-identity grants. Full audit log.

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