Enabling Agent Access

Prerequisites

• An active WorkSpaces Applications fleet (Always-On or On-Demand) — Elastic and multi-session fleets are not supported, and only Windows Server images are supported.
• A stack associated with that fleet (agents cannot connect to a stack without an associated fleet).
• The fleet running a recent WorkSpaces Applications Agent.
• AWS permissions to create/manage stacks; the connecting agent needs the specific agentaccess-mcp actions it calls, scoped by the agentaccess-mcp:StackArn condition key — avoid a blanket agentaccess-mcp:* (see connection-setup.md → IAM permissions).
• (Optional) For screenshot storage: an S3 bucket whose policy grants the AppStream service principal access, and the connecting agent needs s3:PutObject on it. Scope the service-principal grant with aws:SourceAccount / aws:SourceArn (confused-deputy protection), enable encryption at rest (SSE-S3 or SSE-KMS), and enforce encryption in transit (bucket policy denying requests where aws:SecureTransport is false).
• VPC endpoints are not supported for agent access.

How you enable it

Agent access is enabled by supplying an AgentAccessConfig when you CreateStack (or add it later with UpdateStack). If AgentAccessConfig is present, agent access is on and the stack is configured with agent-specific settings instead of the human-user settings.

AgentAccessConfig required fields: Settings (≥1), ScreenResolution, ScreenImageFormat.

Agent actions (Settings[].AgentAction, each with Permission: ENABLED|DISABLED) — you must enable at least one capability:

Other fields:

• ScreenResolution — W_1280xH_720 is the only value the API accepts (single-value enum).
• ScreenImageFormat — PNG or JPEG.
• S3BucketArn + ScreenshotsUploadEnabled: true — optional screenshot storage.
• UserControlMode — VIEW_ONLY, VIEW_STOP (observer can stop the agent), or DISABLED.

CLI example

Enable only the capabilities the workflow needs — this baseline (vision + input) covers standard desktop automation. FORWARD_MCP_TOOLS is optional and only needed for the tool-forwarding workflow; add {"AgentAction": "FORWARD_MCP_TOOLS", "Permission": "ENABLED"} when setting that up (see tool-forwarding.md).

To add screenshot storage, include "S3BucketArn": "arn:aws:s3:::your-bucket", "ScreenshotsUploadEnabled": true.

Updating / removing

• Update: aws appstream update-stack --name <stack-name> --agent-access-config '{...}' supports partial updates — send only the fields you want to change.
• Remove agent access: aws appstream update-stack --name <stack-name> --attributes-to-delete AGENT_ACCESS_CONFIG.
• Config changes take effect on new sessions; already-running sessions keep the settings they launched with.

After enabling

The agent connects to https://agentaccess-mcp.{region}.api.aws/mcp and authenticates the session (streaming URL, or SAML for domain-joined) — see connection-setup.md. Agent behavior is governed by the stack’s AgentAccessConfig, not by parameters on the connection.