Failed to install Node dependencies: unknown error

[garretwilson]

Description

When trying the TypeScript demo according to the online instructions, agentcore dev produces:

Failed to install Node dependencies: unknown error

Steps to Reproduce

1. agentcore create --name MyTsAgent --no-agent
2. cd MyTsAgent
3. agentcore add agent --name TsAgent --type create --build CodeZip --language TypeScript --framework Strands --model-provider Bedrock --memory none
4. agentcore dev

These instructions are exactly according to Get started with the AgentCore CLI in TypeScript

They were performed on Windows 11 using Git Bash for Windows.

Expected Behavior

AgentCore runs in dev mode with no errors.

Actual Behavior

Starting web UI...
Log: agentcore\.cli\logs\dev\dev-20260819-075425.log

Chat UI: http://localhost:8081
Press Ctrl+C to stop

Web UI: [TsAgent] Failed to install Node dependencies: unknown error

In the web UI:

• AgentCore agent inspector: Error
• Failed to install Node dependencies: unknown error
• Failed to install Node dependencies: unknown error

The indicated log provides nothing further:

================================================================================
AGENTCORE DEV LOG
Command: dev
Started: 2026-08-19T12:54:25.122Z
================================================================================

CLI Version

0.27.0

Operating System

Windows

Additional Context

No response

[garretwilson]

I can go into the newly added agent's directory and manually install Node dependencies:

1. cd TsAgent/
2. npm install

added 220 packages, and audited 221 packages in 22s

55 packages are looking for funding
  run `npm fund` for details

found 0 vulnerabilities
npm warn install-scripts 1 package has install scripts not yet covered by allowScripts:
npm warn install-scripts   esbuild@0.28.2 (postinstall: node install.js)
npm warn install-scripts
npm warn install-scripts Run `npm install-scripts ls` to review, or `npm install-scripts approve <pkg>` to allow.

However when I go back to the project root and run agentcore dev, I get Failed to start: spawn npx ENOENT already reported in #1849:

Starting web UI...
Log: agentcore\.cli\logs\dev\dev-20260819-080643.log

Chat UI: http://localhost:8081
Press Ctrl+C to stop

Web UI: [TsAgent] Failed to start: spawn npx ENOEN

It looks like nobody bothered to test AgentCore on Windows: #2010, #2036, #1849 …