LLM-to-LLM Governance

Field	Value
Document ID	ASCEND-SEC-009
Version	2026.04
Last Updated	April 2026
Author	Ascend Engineering Team
Publisher	OW-KAI Technologies Inc.
Classification	Enterprise Client Documentation
Compliance	SOC 2 CC6.1/CC6.2, PCI-DSS 7.1/8.3, HIPAA 164.312, NIST 800-53 AC-2/SI-4

Enterprise-grade governance for AI agent-to-agent communication.

Overview

ASCEND provides LLM-to-LLM governance to control and monitor when one AI agent passes prompts to another. This prevents injection propagation, enforces chain depth limits, and maintains audit trails for compliance.

Fail-Secure Behavior

If the LLM governance service is unreachable or returns an error, agent actions are denied by default. The policy engine's default decision is DENY — there is no allow-by-default configuration.

Architecture

Agent A (source)
    │
    ├── prompt_content
    │
    ▼
┌─────────────────────────────┐
│ PromptSecurityService       │
│   .analyze_llm_chain()      │
├─────────────────────────────┤
│ 1. Check chain depth        │  ← llm_chain_depth_limit (default: 5)
│ 2. Analyze prompt           │  ← Same as prompt injection detection
│ 3. Log to llm_chain_audit   │  ← SHA-256 hash, no raw content
│ 4. Return decision          │
└─────────────────────────────┘
    │
    ▼
Agent B (target)

Configuration

LLM-to-LLM settings are part of org_prompt_security_config:

-- Default settings
scan_llm_to_llm = true           -- Enable chain scanning
llm_chain_depth_limit = 5        -- Max nested agent calls
require_chain_approval = false   -- Require approval for high-risk chains

Chain Depth Limits

Depth	Description	Default Behavior
1	Direct agent call	Allowed
2-5	Nested calls	Allowed (scanned)
>5	Deep nesting	Blocked

API Usage

Analyze Chain Communication

from services.prompt_security_service import PromptSecurityService

service = PromptSecurityService(db, org_id=1)
result = service.analyze_llm_chain(
    source_agent_id="agent-orchestrator",
    target_agent_id="agent-executor",
    prompt_content="Execute the following task...",
    parent_chain_id=None,  # UUID if nested
    source_action_id=12345
)

if result["allowed"]:
    # Proceed with agent communication
    pass
else:
    # Block and log
    print(f"Blocked: {result['reason']}")

Response Format

{
    "allowed": true,
    "chain_id": "550e8400-e29b-41d4-a716-446655440000",
    "depth": 1,
    "injection_detected": false,
    "risk_score": 0,
    "patterns_matched": [],
    "reason": null
}

Blocked Response

{
    "allowed": false,
    "chain_id": "550e8400-e29b-41d4-a716-446655440001",
    "depth": 6,
    "reason": "Chain depth limit exceeded (6 > 5)"
}

Audit Trail

All chain communications are logged to llm_chain_audit_log:

Column	Description
chain_id	Unique UUID for this chain
parent_chain_id	Parent chain for nested calls
depth	Nesting level (1 = direct)
source_agent_id	Agent sending the prompt
target_agent_id	Agent receiving the prompt
prompt_content_hash	SHA-256 hash (no raw content stored)
prompt_length	Character count
injection_detected	Boolean detection result
risk_score	0-100 risk score
patterns_matched	Array of matched pattern IDs
status	allowed, blocked, escalated
block_reason	Reason if blocked

Query Chain Log

# Via API
GET /api/v1/admin/prompt-security/chain-log?status_filter=blocked

# Response
{
    "total": 5,
    "chains": [
        {
            "chain_id": "...",
            "depth": 6,
            "source_agent_id": "orchestrator",
            "target_agent_id": "executor",
            "status": "blocked",
            "block_reason": "Chain depth limit exceeded (6 > 5)"
        }
    ]
}

Detection Patterns

The same patterns used for prompt injection apply to LLM-to-LLM communication. Key patterns for chain attacks:

Pattern ID	Description	Severity
PROMPT-020	Chain injection propagation	Critical
PROMPT-001	Direct instruction override	Critical
PROMPT-004	Jailbreak mode attempts	Critical

PROMPT-020 Pattern

Detects when an agent is instructed to propagate malicious prompts:

\b(pass|forward|relay|send|propagate)\s+(this|these|the\s+following)\s+(instructions?|commands?|prompts?|messages?)\s+(to|for)\s+(the\s+)?(next|other|downstream|target|receiving)\s*(agent|AI|model|LLM|assistant)?\b

Use Cases

1. Orchestrator-Worker Pattern

User Request
    │
    ▼
[Orchestrator Agent]──┬──► [Worker Agent 1]
    chain_id: A       │
                      ├──► [Worker Agent 2]
                      │    chain_id: B, parent: A
                      │
                      └──► [Worker Agent 3]
                           chain_id: C, parent: A

2. Recursive Agent Calls

[Research Agent]
    │ depth=1
    ▼
[Search Agent]
    │ depth=2
    ▼
[Summarize Agent]
    │ depth=3
    ▼
[Verify Agent]
    │ depth=4
    ▼
[Format Agent]
    │ depth=5 ← At limit
    ▼
[Export Agent]  ← BLOCKED (depth=6)

3. Cross-Tenant Prevention

Chain governance ensures agents from one tenant cannot inject prompts into agents of another tenant through the organization_id filter.

Integration Points

MCP Governance

When using MCP (Model Context Protocol) servers, chain governance integrates automatically:

# In mcp_governance_service.py
if action_type == "llm_call":
    chain_result = prompt_service.analyze_llm_chain(
        source_agent_id=current_agent,
        target_agent_id=target_agent,
        prompt_content=mcp_request.prompt
    )
    if not chain_result["allowed"]:
        return MCPDenied(reason=chain_result["reason"])

Action Submission

Chain analysis is part of the standard /api/v1/actions/submit flow when action_type indicates inter-agent communication.

Compliance

• SOC 2 CC6.1: Access control and monitoring
• NIST 800-53 SI-10: Information Input Validation
• OWASP LLM Top 10: LLM01 (Prompt Injection), LLM07 (Insecure Plugin Design)

Best Practices

1. Set reasonable depth limits - Default of 5 is sufficient for most architectures
2. Monitor blocked chains - Review /chain-log regularly for anomalies
3. Use unique agent IDs - Helps with audit trail analysis
4. Hash sensitive content - Only hashes stored, never raw prompts
5. Enable in monitor mode first - Evaluate before enforcing blocks