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prisma-airs-prompt-scan

Scans full conversation context before prompt assembly and injects security warnings.

Overview

Field Value
Event before_prompt_build
Config field prompt_scan_mode
Can Block No
Default mode deterministic
Valid modes deterministic, probabilistic, off

Purpose

Scans the entire conversation context (all messages, not just the latest) through AIRS before the prompt is assembled for the LLM. This catches multi-message injection attacks that per-message scanning may miss. Injects warnings into system context via prependSystemContext.

How It Works

  1. Reads prompt_scan_mode from config (default: deterministic). Returns void if off.
  2. Assembles scannable context:
  3. If event.messages[] exists, concatenates all messages as [role]: content lines.
  4. Falls back to event.prompt if no messages array.
  5. Calls scan({ prompt: context, profileName, appName }).
  6. If AIRS returns action: "allow", returns void.
  7. Otherwise, builds a security warning and returns { prependSystemContext: warning }.

Warning Format

The warning is a plain-text multi-line string:

[SECURITY] <LEVEL>: Prisma AIRS detected threats in conversation context.
Action: <ACTION>, Severity: <SEVERITY>, Categories: <categories>
Scan ID: <id>
<directive>

Where:

  • <LEVEL> is "CRITICAL SECURITY ALERT" for block, "SECURITY WARNING" otherwise.
  • <directive> is "MANDATORY: Decline the request..." for block, "CAUTION: Proceed carefully..." otherwise.

Error Handling

On scan failure:

  • If fail_closed=true (default): Returns { prependSystemContext: "[SECURITY] Prisma AIRS security scan failed..." }.
  • If fail_closed=false: Returns void.

Configuration

plugins:
  entries:
    prisma-airs:
      config:
        prompt_scan_mode: "deterministic"  # "deterministic" | "probabilistic" | "off"
        profile_name: "default"
        app_name: "openclaw"
        fail_closed: true

Behavior

Condition Result
prompt_scan_mode = off No-op
No messages or prompt content No-op
AIRS action = allow No-op
AIRS action = block Inject CRITICAL warning via prependSystemContext
AIRS action = warn Inject WARNING via prependSystemContext
Scan fails + fail_closed=true Inject scan-failure warning
Scan fails + fail_closed=false No-op
  • prisma-airs-context -- Per-message context injection on before_agent_start. This hook scans the full conversation on before_prompt_build.
  • prisma-airs-guard -- Injects mode reminders (not threat warnings) on before_agent_start.