Quick answer
Add AgentCore Harness capabilities in layers: start with one allowlisted tool, then add packaged Skills, and only then add private-network access. From n8n, the AWS verified node can configure or invoke a harness that uses Code Interpreter, Browser, AgentCore Gateway, remote MCP servers, and Skills from AWS, Git, S3, or the filesystem.
Every layer requires matching execution-role permissions, credentials, network reachability, and tests. A tool appearing in configuration does not prove the agent is authorized, safe, or able to reach its backend.
Tools and Skills solve different problems
| Capability | Purpose | Typical risk |
|---|---|---|
| Code Interpreter | Execute bounded code in an isolated environment | Data exposure, resource consumption, generated-file handling |
| Browser | Navigate web content | Untrusted pages, prompt injection, external side effects |
| AgentCore Gateway | Invoke governed targets | Identity propagation, target authorization, downstream limits |
| Remote MCP | Discover and call MCP tools | Server trust, tool drift, credentials, network egress |
| Skill | Load instructions and supporting resources on demand | Source provenance, stale guidance, hidden operational assumptions |
A tool performs an action or retrieves data. A Skill gives the agent reusable procedures and resources. Skills follow the Agent Skills packaging model, with metadata available for discovery and fuller instructions loaded when relevant. AWS documents sources including its catalog, Git, S3, and filesystem locations.
Use progressive capability rollout
- Start with no write-capable tools.
- Add one read-only tool and a fixed evaluation set.
- Restrict the available tool names or patterns.
- Verify authentication, authorization, timeouts, and error handling.
- Add the minimum Skill needed to guide the task.
- Inspect traces to confirm the agent loads and uses it as expected.
- Add a write tool only after confirmation and idempotency are designed.
For private Git Skills, AWS documents using an API-key credential provider for the access token. For S3 Skills, scope ListBucket and GetObject to the intended bucket and prefix. Do not grant an execution role access to every repository or bucket because one Skill needs a single path.
Plan remote MCP and Gateway identity
Remote MCP and Gateway connections cross a trust boundary. Record:
- the operator and provenance of the server or target;
- the transport and network route;
- the authentication method and credential owner;
- tool names and schemas allowed to the harness;
- whether calls act as the end user or as the agent;
- downstream quotas, timeouts, retries, and audit logs;
- how tool additions or schema changes are reviewed.
Treat tool descriptions and returned content as untrusted input. A model choosing a tool is not authorization for the underlying business action.
What changes in VPC mode
VPC mode places the harness in selected subnets and security groups. It is useful for private services, but requires a full path review.
AWS documents private managed-image pull requirements for Harness VPC mode: interface endpoints for ECR API and ECR Docker plus an S3 gateway endpoint, together with region-scoped private ECR pull permissions on the execution role. That path can avoid NAT for the managed image pull; it does not prove that every model, MCP server, Git source, or external API is reachable without egress.
Check:
- subnet routes and available IP capacity;
- security-group egress and backend ingress;
- private DNS and VPC endpoint policies;
- endpoint Regions and repository Regions;
- model-provider and external-tool connectivity;
- CloudWatch and telemetry paths;
- cost ownership for interface endpoints, NAT, data transfer, and dependent services.
Production review checklist
- Pin or approve Skill and MCP source revisions.
- Use exact resource ARNs and narrow tool allowlists.
- Store API and OAuth secrets in managed credential providers.
- Separate read, write, and administrative tools.
- Test prompt injection, malformed tool output, timeouts, and partial failures.
- Require confirmation for consequential writes.
- Bound iterations, time, and tokens.
- Trace each n8n execution to the Harness invocation.
- Re-test connectivity and permissions after any VPC, tool, or Skill change.
Use the n8n AgentCore harness planner to generate an architecture review checklist before configuration.
Frequently asked questions
Which tools can AgentCore Harness use from n8n?
AWS documents built-in Code Interpreter and Browser tools, AgentCore Gateway, remote MCP servers, and configured tools. Availability and permissions depend on current AgentCore support.
What is an AgentCore Skill?
A Skill is a packaged set of instructions and supporting resources, using the Agent Skills specification, that the harness can load when relevant. Sources include AWS catalogs, Git, S3, and filesystem paths.
Does VPC mode remove every need for internet egress?
No. Private ECR image pulls can use required ECR and S3 endpoints, but model providers, remote MCP servers, Git sources, APIs, and other tools may still need approved egress or private connectivity.
Should every connected tool be available to the model?
No. Start with a minimal allowlist, use read-only scopes where possible, and add side-effecting tools only with authorization, confirmation, idempotency, and audit controls.
Continue by decision
- AgentCore Harness setup for n8n
- n8n AI Agent vs. Harness
- Security, cost, and cleanup
- Memory, actor, and session guide
Official sources
- AWS AgentCore Harness tools
- AWS AgentCore Harness Skills
- AWS AgentCore Harness security and network configuration
Source check: August 8, 2026. Verify current tool types, Skill sources, IAM actions, VPC endpoints, network behavior, Regions, quotas, and prices before use.