d3k

$27

• If d3k is missing, install dev3000 globally (prefer Bun):

bun install -g dev3000

Fallback if Bun is unavailable:

npm install -g dev3000

• Start d3k as the runtime (preferred default in agent shells):

d3k --no-agent --no-tui -t

• Keep d3k running while editing code. Do not start a second dev server with npm/bun dev.

Codex Fresh Browser/Profile Startup

Use this workflow when the user asks Codex to start d3k with a fresh browser/profile.

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Close any stale agent-browser daemon before launching with --profile. Otherwise agent-browser will reuse the existing daemon and print --profile ignored.

d3k agent-browser close --all

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Start the app through d3k in servers-only mode and keep that command running. In Codex, this is more reliable than asking d3k to launch the browser itself when a fresh profile is required.

d3k --no-agent --no-skills --servers-only --command "npm run dev -- -H 127.0.0.1 -p 3000" --port 3000 --startup-timeout 90 --no-tui

Adjust the package-manager command and port for the project. Prefer --command over --script when passing framework flags. For npm scripts, put flags after --; otherwise tools like Next.js can interpret the port as a project directory.

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Verify the server before opening more browser windows:

curl -I http://127.0.0.1:3000

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Open the fresh profile as a separate browser step:

d3k agent-browser --profile /tmp/d3k-fresh-profile --headed open http://127.0.0.1:3000

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Sanity-check the opened page:

d3k agent-browser get title

d3k agent-browser snapshot -i

d3k errors

Practical rules:

• Prefer 127.0.0.1 for this workflow. If localhost hangs or flips between IPv4/IPv6 behavior, do not keep retrying browser launches.

• If curl -I hangs, the server is wedged even if the port appears occupied; restart the d3k server process before opening a browser.

• In servers-only mode there is no d3k-monitored CDP browser. Use regular d3k agent-browser commands, not d3k cdp-port.

• In sandboxed agent environments, rerun local-network checks and agent-browser opens outside the sandbox when sandbox networking blocks access to 127.0.0.1.

Debugging Commands

Use these first before ad-hoc log scraping:

d3k errors --context

d3k logs -n 200

d3k logs --type browser

d3k logs --type server

CDP Browser Control

Use the already-monitored browser session instead of launching a separate automation browser.

d3k agent-browser open http://localhost:3000

d3k agent-browser snapshot -i

d3k agent-browser click @e2

d3k agent-browser screenshot /tmp/d3k-current.png

d3k agent-browser auto-connects to the active session's browser via CDP. To target a different browser, run d3k agent-browser connect <port> first.

Browser Tool Choice

Use the browser tool that matches the task instead of treating them as interchangeable:

• agent-browser

• Default choice.

• Best for generic web apps and for driving the exact headed browser session that d3k is already monitoring via CDP.

• Use it when you need snapshot, ref-based click, fill, or to reproduce what the user sees in the monitored tab.

• next-browser

• Next.js-specific tool.

• Best for React/Next introspection: tree, errors, logs, routes, project, PPR inspection, and related Next dev-server signals.

• It is not a drop-in replacement for agent-browser: no accessibility snapshot, no ref-based click, and no fill.

• It launches its own daemon/browser flow and does not use the d3k session's CDP port.

Practical rule:

• Need to drive the same browser d3k is monitoring: use agent-browser.

• Need Next.js component tree or Next-specific diagnostics: use next-browser.

Examples:

# Same monitored browser session

d3k agent-browser snapshot -i

d3k agent-browser click @e2

# Next.js-specific inspection

d3k next-browser open http://localhost:3000

d3k next-browser tree

d3k next-browser errors

d3k next-browser logs

Artifacts to Read

• ~/.d3k/{project}/d3k.log

• ~/.d3k/{project}/logs/

• ~/.d3k/{project}/screenshots/

• ~/.d3k/{project}/session.json

Operating Rules

• Prefer headed mode for interactive debugging.

• Use --headless only for CI or when explicitly requested.

• Use --servers-only only when browser monitoring is intentionally disabled.