What are the security risks of a planner-executor agent architecture and how do I mitigate them?

Planner-executor agent architectures face security risks primarily from expanded attack surfaces in multi-agent orchestration and dynamic workflows, which can lead to workflow hijacking, tool misuse, and unauthorized actions. Mitigations focus on strict controls over agent interactions, tool usage, and continuous evaluation to prevent and detect malicious activities.

Here are concrete controls to mitigate these risks:

• Implement least-privilege tools per specialist agent and strict delegation schemas to prevent workflow hijacking and tool misuse (MAESTRO Layer 3: Agent Frameworks).
• Use coordinator-owned final writes and bounded subagent outputs to limit the impact of malicious subtask framing and prompt injection through inter-agent messages (MAESTRO Layer 3: Agent Frameworks).
• Harden sandboxes, restrict networks, and scope credentials for deployment infrastructure to prevent container compromise and lateral movement (MAESTRO Layer 4: Deployment and Infrastructure).
• Require explicit tool approvals for sensitive actions and enforce file path conventions to control tool execution surfaces (MAESTRO Layer 4: Deployment and Infrastructure).
• Establish immutable event logs and separate operational dashboards for grader results to counter grader manipulation and log injection (MAESTRO Layer 5: Evaluation and Observability).
• Conduct human sampling of passed outcomes and alert on repeated max-iteration failures to detect hidden failed iterations and over-reliance on "satisfied" signals (MAESTRO Layer 5: Evaluation and Observability).
• Utilize Intent-Based Access Control (IBAC) to ensure every consequential action aligns with the agent's authorized intent, defending against external manipulation, adversarial prompt injection, and model hallucination (MAESTRO Layer 3: Agent Frameworks, Layer 6: Security & Compliance).
• Implement tool-call validation gates including schema validation, allowlisted tools/actions, and parameter constraints to prevent tool misuse and unsafe tool calls (MAESTRO Layer 3: Agent Frameworks, Layer 7: Agent Ecosystem).
• Enforce per-task and per-agent budgets, circuit breakers, and timeout enforcement to mitigate rate limit and resource exhaustion attacks (MAESTRO Layer 3: Agent Frameworks, Layer 4: Deployment and Infrastructure).
• Conduct continuous, automated security evaluation using golden datasets, robust eval harnesses, and automated red-teaming tools to identify and prevent regressions (MAESTRO Layer 5: Evaluation and Observability).