Install, authenticate, verify, and run the Devin CLI through Tejus's ACP integration on Windows.

Tejus connects to the local Devin CLI through the devin executable and its Agent Client Protocol (ACP) server, devin acp. Devin owns the account, credentials, model access, commands, and provider service; Tejus supplies the durable task, repository environment, transcript, approvals, context controls, review surfaces, and Git workflow around the session.

Install

Run Devin's official Windows installer from PowerShell:

irm https://static.devin.ai/cli/setup.ps1 | iex

Open a new PowerShell window, then verify the installed executable:

devin --version

Tejus looks for devin on your PATH. If it is not there, Tejus also checks %LOCALAPPDATA%\devin\cli\bin\devin.exe and %LOCALAPPDATA%\devin\bin\devin.exe.

Authenticate

In Tejus, open Settings → Agent providers, expand Devin under Provider tools, and click Sign in; Tejus runs devin auth login in a terminal window. Choose your Devin or Windsurf login and follow the browser or enterprise sign-in prompts. Or run it yourself:

devin auth login
devin auth status

Tejus reads Devin's stored credentials from %APPDATA%\devin\credentials.toml. Instead of a login you can provide WINDSURF_API_KEY (or DEVIN_API_KEY). Prefer the interactive login for normal desktop use. If you use a key, set it as a Windows user environment variable and restart Tejus, or add it to Devin's Environment section under Provider tools with the secret switch on. Keep it out of repositories, shell history, screenshots, and task transcripts.

Verify

From a disposable repository, verify the same CLI Tejus will launch:

devin --version
devin auth status
devin models list --format json

Then start Devin interactively and make one harmless read-only request:

devin

The devin acp subcommand is a JSON-RPC server for ACP-aware hosts such as Tejus. Do not use it as an interactive terminal session.

Connect to Tejus

Enable Devin

Open Settings → Agent providers, keep Devin enabled under Provider activity, and click Refresh status.

Confirm authentication

Tejus marks Devin as signed in when it finds an API key in the environment or in Devin's stored credentials. Otherwise the status reads “Devin CLI is installed. Run devin auth login to authenticate locally, or set WINDSURF_API_KEY before starting a session.”

Check models and commands

Tejus reads models from devin models list --format json and the slash commands advertised by the Devin ACP server. Confirm that the expected model choices and commands appear before starting important work.

Start a bounded task

Use a clean test repository and conservative permissions. Verify Plan mode, a normal response, and one safe tool call before granting broader access.

Capabilities in Tejus

Devin sessions can expose:

Fresh and resumed ACP sessions tied to the owning Tejus task
Models and slash commands advertised by the installed Devin CLI
Normal execution and Devin's Plan mode
Context compaction through Devin's /compact command
File and image attachments
MCP server configuration passed to the session at startup
Tool calls, command output, file changes, and assistant text
Account usage when Tejus can read it from the signed-in Devin account
Tejus's terminal, browser, diff, checkpoint, worktree, and Git delivery surfaces

The selected model is applied when the Devin process starts.

Tejus does not support live steering of a running Devin turn. Queue a follow-up or wait for the current turn to settle instead of assuming another provider's active-turn controls are available.

Stalled sessions and recovery

If the Devin process stops responding while still running, Tejus restarts the session and asks it to continue, showing “Devin stopped responding; restarting this session automatically and continuing the task.” This happens at most three times per task within 30 minutes. If Devin cannot load a previous session's data, Tejus starts a fresh session instead.

Recovery is different from intentionally pausing a goal or interrupting a task. Inspect the resulting task state before repeating work with external side effects.

Configuration

Keep Devin configuration in locations supported by the installed CLI. Devin binary path (in Devin's Runtime section under Provider tools) must point to the devin executable, not its configuration directory.

When behavior differs between Devin and Tejus, compare the exact executable, version, working directory, account, model, environment, and configuration file selected by the CLI.

Updating

Use Devin's supported update method, or rerun the official installer, then restart Tejus, especially when the ACP command set, authentication, models, or session configuration changed. Tejus does not run Devin updates for you.

Troubleshooting

Devin is not detected

Tejus shows “Devin CLI (devin) is not installed or not on PATH.”

Run devin --version from a new PowerShell window.
Confirm the installer folder is on PATH, or that devin.exe exists under %LOCALAPPDATA%\devin.
Check the Devin binary path in Tejus.
Restart Tejus after installation or environment changes.

Devin