AgentGuard

AgentGuard is Runlayer’s purpose-built ML model for agent reasoning security. Where per-call tool scanners look at one input or output at a time, AgentGuard watches the agent’s trajectory across a session and detects when behavior diverges from the user’s intent. AgentGuard surfaces inside Sessions on each agent turn.

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What AgentGuard detects

AgentGuard is built to catch agentic attacks that per-call scanners miss:

• Output-steering injection — a tool output contains hidden instructions that redirect the agent
• Sudden reasoning pivots — the agent’s reasoning abruptly changes direction with no basis in the conversation
• Slow-chain drift — gradual, step-by-step divergence from the original task

It distinguishes legitimate behavior changes from genuine misalignment. A high-privilege operation that matches user intent is allowed; an agent autonomously taking the same action outside the requested task is not.

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Reading the turn scores

Each scored turn in Sessions has three bars. A full bar is good. A bar turns red when it drops below 70%. A turn is flagged when the combined drift (alignment plus both stability shifts) or the classifier crosses its threshold. The Strict, Balanced and Moderate sensitivity levels move those thresholds; at Moderate both must agree before a turn is flagged, unless the classifier is unavailable, in which case the drift check decides alone.

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Configuration

AgentGuard is configured under Settings → Security Scanners → Session scanning.

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Agent monitoring

The main toggle for AgentGuard.

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Block later tool calls when any scanner blocks

When any per-call scanner blocks a tool call, every later tool call in the session is denied too. The agent keeps running but can’t use tools. To end a session yourself, use Stop on the session. With this setting off, nothing enforces a session-level block, so Sessions shows that session as Flagged instead of Blocked.

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Rollout guidance

1. Start in Alert so you can see what AgentGuard would do without affecting agents in production.
2. Review Flagged sessions in Sessions and confirm the verdicts match your security policy.
3. Move Agent monitoring to Block for high-risk teams or agents first.
4. Enable Block later tool calls when any scanner blocks once your per-call scanner tuning is stable.

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Requirements

• Sessions enabled for the workspace (Settings → Agent session monitoring)
• A deployment with ToolGuard capabilities

If AgentGuard options do not appear in Security Scanners, confirm both above.

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