Agent Gateway multi-agent security

Critical Enforcement Rules & Rationale

Gcloud Release Tracks: Always use the exact release tracks specified in the commands (e.g.,
```
gcloud beta network-services agent-gateways
```
). Omitting these prefixes causes commands to fail because Agent Gateway features are located in specialized, non-default namespaces.
API Enablement: Include
```
modelarmor.googleapis.com
```
in the API enablement list when setting up guardrails. Excluding it prevents Model Armor policies and filters from successfully attaching to the Gateway.
Egress Verification: Egress policy verification requires using the Python script (scripts/verify_egress_policies.py), not
```
curl
```
. Egress gateways rely on runtime SDK lifecycle handling and JWT context that a standard curl command cannot simulate correctly.
Model Armor Keys: In
```
model-armor-config.yaml
```
, always include both
```
piAndJailbreakFilterSettings
```
and
```
sdpFilterSettings
```
(
```
filterEnforcement: ENFORCE
```
). Invalid or missing filters cause deployment validation failures or lead to silent bypasses of the guardrails.
Subnet Private Access: Any subnet hosting a Private Service Connect network attachment for Egress Gateways must have
```
private_ip_google_access = true
```
enabled in Terraform. Disabling this blocks connectivity to Google-managed endpoints, causing total routing failures for agents.
Direct Delivery: Immediately provide the requested architecture, configuration files, CLI commands, scripts, and diagrams in full. Do not stop at a planning phase, do not generate a plan artifact, and do not ask for user confirmation before delivering outputs.
No Infrastructure Execution: Do not attempt to run deployment or verification commands (such as
```
gcloud
```
,
```
kubectl
```
,
```
terraform
```
, or
```
curl
```
) against real cloud resources during design. You are generating plan configurations, not executing them.

[!IMPORTANT] Just-In-Time (JIT) Resource Loading Protocol: Inspect template files in assets/ and executable scripts in scripts/ using
view_file
as needed for extended configurations, deployment scripts, and test suites.

Quick Reference: Required Filenames

Always generate files with these exact names when requested:

```
agw-ingress-config.yaml
```
(assets/agw-ingress-config.yaml)
```
agw-egress-config.yaml
```
(assets/agw-egress-config.yaml)
```
agw-authz-extension.yaml
```
(assets/agw-authz-extension.yaml)
```
agw-authz-policy.yaml
```
(assets/agw-authz-policy.yaml)
```
model-armor-config.yaml
```
(assets/model-armor-config.yaml)
```
sgp-policy.yaml
```
(assets/sgp-policy.yaml)
```
iap-policy.json
```
(assets/iap-policy.json)
```
model-armor-payload.json
```
(assets/model-armor-payload.json)

1. Dual Ingress & Egress Architecture Design (

dual_ingress_egress_architecture_design

)

Ingress Pattern:
```
CLIENT_TO_AGENT
```
fronted by Ingress Control Plane (Agent Gateway, Model Armor).
Egress Pattern:
```
AGENT_TO_ANYWHERE
```
utilizing Egress Control Plane (Agent Gateway,
```
roles/iap.egressor
```
CEL policies, Cloud DNS) and Egress Data Plane (PSC Interface, Cloud Run, PSC Google APIs Global Endpoint), coordinated via Agent Registry & Agent Engine runtime.

Mermaid Diagram:

mermaid

graph TD
    Client["External Clients"] -->|HTTPS / MCP| GLB["Global Load Balancer"]
    GLB --> Ingress["Ingress Agent Gateway (CLIENT_TO_AGENT)"]
    Ingress --> MA["Model Armor (CONTENT_AUTHZ)"]
    MA --> Agent["Agent Engine Agents (BillingAgent, SupportAgent, FraudAgent)"]
    Agent --> Egress["Egress Agent Gateway (AGENT_TO_ANYWHERE)"]
    Egress --> PSC["Private Service Connect Network Attachment"]
    PSC --> Tools["Private MCP Tool Backends"]

2. Ingress & Egress Guardrail Policy Config (

ingress_and_egress_guardrail_policy_config

)

When requested for Ingress & Egress guardrail policy configs, you MUST generate and create all required files in the workspace:

agw-ingress-config.yaml

(assets/agw-ingress-config.yaml): Declares

governedAccessPath: CLIENT_TO_AGENT

with protocols

HTTP

and

MCP

agw-egress-config.yaml

(assets/agw-egress-config.yaml): Declares

governedAccessPath: AGENT_TO_ANYWHERE

with protocol

MCP

```
agw-authz-extension.yaml
```
(assets/agw-authz-extension.yaml): Configures AuthzExtension service for IAP authorization.
```
agw-authz-policy.yaml
```
(assets/agw-authz-policy.yaml): Configures
```
AuthzPolicy
```
action
```
ALLOW
```
targeting both Ingress and Egress gateways.

iap-policy.json

(assets/iap-policy.json): Binds

roles/iap.egressor

with CEL condition checking

iap.googleapis.com/mcp.toolName == 'get_account_balance' && iap.googleapis.com/mcp.tool.isReadOnly == true

model-armor-config.yaml

(assets/model-armor-config.yaml): Enables

piAndJailbreakFilterSettings

and

sdpFilterSettings

with

filterEnforcement: ENFORCE

```
sgp-policy.yaml
```
(assets/sgp-policy.yaml): Implements Natural Language Constraints blocking transactions > $1000 and sanitizing PII.

3. Ingress & Egress Infrastructure Deployment (

ingress_and_egress_infrastructure_deployment

)

Inspect and provide the step-by-step

gcloud

CLI commands from scripts/deploy_infrastructure.sh:

Enable Required APIs:

compute

networkservices

networksecurity

modelarmor

iap

agentregistry

serviceextensions

, and

aiplatform

Import Agent Gateways: Ingress (

agw-ingress-config.yaml

) and Egress (

agw-egress-config.yaml

) via

gcloud alpha network-services agent-gateways import

Import Authz Extension:

agw-authz-extension.yaml

via

gcloud beta service-extensions authz-extensions import

Import Authz Policy:

agw-authz-policy.yaml

via

gcloud beta network-security authz-policies import

4. Ingress & Egress Security Validation (

ingress_and_egress_security_validation

)

When validating security for Ingress and Egress:

Ingress 403 Unauthenticated Test: Provide the copy-pasteable verification curl command from scripts/validate_ingress_unauth.sh sending an unauthenticated POST request to the Reasoning Engine endpoint expecting HTTP 403 Forbidden.
Python Egress Verification Script (MUST use Python script snippet, NOT curl): Provide the Python verification script snippet from scripts/verify_egress_policies.py sending JSON-RPC
```
tools/call
```
requests (
```
get_account_balance
```
) through the Egress Gateway to verify HTTP 200 for allowed tools.
Model Armor Test Payload: Generate
```
model-armor-payload.json
```
(assets/model-armor-payload.json) containing prompt injection/jailbreak instructions.

5. Troubleshooting Ingress & Egress Failures (

troubleshooting_ingress_and_egress_failures

)

Ingress 403 (Client-to-Agent):
- Root Cause: Unauthenticated client requests or missing/invalid OAuth 2.0 / IAP identity tokens.
- OAuth Configuration Steps:
  1. Configure OAuth 2.0 Client ID credentials in Google Cloud Console.
  2. Grant the client identity / service account
    roles/iap.httpsResourceAccessor
    permission.
  3. Exchange credentials with Google OAuth to acquire an OIDC / OAuth ID token.
  4. Pass the token in the
    Authorization: Bearer <TOKEN>
    header.
- Verification Command: Provide the curl command from scripts/verify_ingress_auth.sh.
Egress 403 (Agent-to-Anywhere):
- Root Cause: Missing
```
roles/iap.egressor
```
  IAM bindings on the Agent Identity, malformed principal ID, or mismatched CEL condition on tool metadata.
- Fix Command: Provide the exact
```
gcloud
```
  command from scripts/fix_egress_iap.sh.

6. Hybrid VPN Connectivity & Egress Routing (

hybrid_vpn_connectivity_egress_routing

)

Terraform HCL: Refer to baseline Terraform config in assets/main.tf for VPC, subnets (
```
private_ip_google_access = true
```
), PSC network attachment, Cloud DNS private forwarding for
```
aws.internal.
```
, and HA VPN gateway/router.
Egress Gateway Config (
agw-egress-config.yaml
): Generate configuration declaring
```
governedAccessPath: AGENT_TO_ANYWHERE
```
, pointing to the PSC network attachment, and referencing
```
aws.internal.
```
in
```
dnsPeeringConfig
```
(see assets/agw-egress-config.yaml).
Python SDK Deployment Script: Refer to scripts/hybrid_vpn_agent.py for the complete script initializing Vertex AI with
```
agent_to_anywhere_config
```
referencing the Egress Gateway, enabling telemetry, and deploying
```
HybridAgent
```
using
```
types.IdentityType.AGENT_IDENTITY
```
.

7. Private Egress GKE Internal Load Balancer (

private_egress_gke_internal_load_balancer

)

Expose GKE internal MCP tool server via an Internal Load Balancer (ILB) at literal IP
```
10.0.1.50
```
, connecting via Agent Gateway PSC Interface + Cloud DNS Private zone.
Cloud DNS Record Mapping: Provide the command from scripts/create_gke_dns_record.sh mapping the private domain to GKE's private ILB IP
```
10.0.1.50
```
.
Explicit TLS Warning: Agent Gateway egress does not natively trust self-signed certificates or private enterprise CAs. You must use publicly trusted TLS certificates signed by a trusted Certificate Authority (e.g., Let's Encrypt).

8. Governance Controls Model Armor SGP (

governance_controls_model_armor_sgp

)

When configuring dual safety layers with Model Armor on Ingress and SGP on Egress:

Model Armor Config: Generate

model-armor-config.yaml

(assets/model-armor-config.yaml) with

piAndJailbreakFilterSettings

and

sdpFilterSettings

(

filterEnforcement: ENFORCE

Semantic Governance Policy: Generate
```
sgp-policy.yaml
```
(assets/sgp-policy.yaml) with Natural Language Constraints blocking transactions > $1000 and sanitizing PII.
Curl PATCH Command: Provide the curl command from scripts/enforce_sgp_patch.sh to update
```
authzExtensions
```
with
```
sgpEnforcementMode
```
set to
```
ENFORCE
```
.

9. Multi-Agent Cloud Run Egress Routing (

multi_agent_cloud_run_egress_routing

)

Do NOT produce a plan artifact or stop at planning. When configuring multi-agent Cloud Run egress routing, you MUST directly provide and generate ALL required components:

Egress Gateway Config (
agw-egress-config-run.yaml
): Generate configuration declaring
```
governedAccessPath: AGENT_TO_ANYWHERE
```
, PSC network attachment, and DNS peering for
```
*.run.app
```
(see assets/agw-egress-config-run.yaml).
Register Cloud Run Services in Agent Registry: Provide the registration commands from scripts/register_cloud_run_services.sh registering all 3 Cloud Run services (
```
marketing-tool-service
```
,
```
sales-tool-service
```
,
```
support-tool-service
```
) in the
```
us-east4
```
Agent Registry.
iap-policy.json
(Multi-Agent): Generate
```
iap-policy.json
```
(assets/iap-policy-multi-agent.json) containing all 3
```
principal://
```
bindings in the
```
members
```
list under
```
roles/iap.egressor
```
.
Python SDK Deployment Script: Refer to scripts/multi_agent_cloud_run.py for the complete GenAI SDK deployment script.

10. Advanced Model Armor Filtering (

advanced_model_armor_filtering

)

For custom keyword matching, configure

userDefinedFilterSettings

(see assets/model-armor-advanced.yaml).

11. Known Traps & Gotchas (

known_traps_and_gotchas

)

network_attachment
is
ForceNew
: Enabling Semantic Governance Policies (SGP) or modifying network attachments after the initial Terraform apply will force-recreate the gateway resource. If not managed carefully, this can cause dependency deadlocks during destroy operations. Plan infrastructure sequencing accordingly.
Authz Policy Limit: An Agent Gateway allows at most 4 custom authorization policies attached concurrently. Ensure your security posture consolidates rules within this limit.

google-cloud-solution-multi-agent-security

NPX Install

Tags

SKILL.md Content

Agent Gateway multi-agent security

Critical Enforcement Rules & Rationale

Quick Reference: Required Filenames

1. Dual Ingress & Egress Architecture Design (
`dual_ingress_egress_architecture_design`
)

2. Ingress & Egress Guardrail Policy Config (
`ingress_and_egress_guardrail_policy_config`
)

3. Ingress & Egress Infrastructure Deployment (
`ingress_and_egress_infrastructure_deployment`
)

4. Ingress & Egress Security Validation (
`ingress_and_egress_security_validation`
)

5. Troubleshooting Ingress & Egress Failures (
`troubleshooting_ingress_and_egress_failures`
)

6. Hybrid VPN Connectivity & Egress Routing (
`hybrid_vpn_connectivity_egress_routing`
)

7. Private Egress GKE Internal Load Balancer (
`private_egress_gke_internal_load_balancer`
)

8. Governance Controls Model Armor SGP (
`governance_controls_model_armor_sgp`
)

9. Multi-Agent Cloud Run Egress Routing (
`multi_agent_cloud_run_egress_routing`
)

10. Advanced Model Armor Filtering (
`advanced_model_armor_filtering`
)

11. Known Traps & Gotchas (
`known_traps_and_gotchas`
)

google-cloud-solution-multi-agent-security

NPX Install

Tags

SKILL.md Content

Agent Gateway multi-agent security

Critical Enforcement Rules & Rationale

Quick Reference: Required Filenames

1. Dual Ingress & Egress Architecture Design (dual_ingress_egress_architecture_design)

2. Ingress & Egress Guardrail Policy Config (ingress_and_egress_guardrail_policy_config)

3. Ingress & Egress Infrastructure Deployment (ingress_and_egress_infrastructure_deployment)

4. Ingress & Egress Security Validation (ingress_and_egress_security_validation)

5. Troubleshooting Ingress & Egress Failures (troubleshooting_ingress_and_egress_failures)

6. Hybrid VPN Connectivity & Egress Routing (hybrid_vpn_connectivity_egress_routing)

7. Private Egress GKE Internal Load Balancer (private_egress_gke_internal_load_balancer)

8. Governance Controls Model Armor SGP (governance_controls_model_armor_sgp)

9. Multi-Agent Cloud Run Egress Routing (multi_agent_cloud_run_egress_routing)

10. Advanced Model Armor Filtering (advanced_model_armor_filtering)

11. Known Traps & Gotchas (known_traps_and_gotchas)

1. Dual Ingress & Egress Architecture Design (
`dual_ingress_egress_architecture_design`
)

2. Ingress & Egress Guardrail Policy Config (
`ingress_and_egress_guardrail_policy_config`
)

3. Ingress & Egress Infrastructure Deployment (
`ingress_and_egress_infrastructure_deployment`
)

4. Ingress & Egress Security Validation (
`ingress_and_egress_security_validation`
)

5. Troubleshooting Ingress & Egress Failures (
`troubleshooting_ingress_and_egress_failures`
)

6. Hybrid VPN Connectivity & Egress Routing (
`hybrid_vpn_connectivity_egress_routing`
)

7. Private Egress GKE Internal Load Balancer (
`private_egress_gke_internal_load_balancer`
)

8. Governance Controls Model Armor SGP (
`governance_controls_model_armor_sgp`
)

9. Multi-Agent Cloud Run Egress Routing (
`multi_agent_cloud_run_egress_routing`
)

10. Advanced Model Armor Filtering (
`advanced_model_armor_filtering`
)

11. Known Traps & Gotchas (
`known_traps_and_gotchas`
)