cokacremote

cokacremote lets ChatGPT or another MCP client work directly on a remote Linux server.

In simple terms, it gives an AI client tools to do things you would normally do over SSH: run shell commands, inspect logs, edit files, install packages, build projects, and manage services.

MCP stands for Model Context Protocol. It is a standard that lets an AI client call tools provided by another program. You do not need to understand the protocol internals to use cokacremote.

ChatGPT or another MCP client
            |
            | MCP over HTTPS
            v
       cokacremote
            |
            v
       Linux server
       |- run commands
       |- read/write files
       |- install packages
       |- build and test code
       `- manage processes and services

You can run cokacremote continuously on a VPS or EC2 instance and connect to it remotely over MCP Streamable HTTP.

Warning

cokacremote is intentionally powerful. It has no sandbox, command allowlist, execution approval, or path restrictions. If the service runs as root, an authenticated MCP client can change or delete anything on the server. Use HTTPS, strong authentication, and only connect trusted clients.

Quick start

If you already have a Linux server and Node.js 22+, the shortest local test is:

git clone https://github.com/kstost/cokacremote.git
cd cokacremote
npm install
npm run build

export MCP_AUTH_TOKEN="$(openssl rand -hex 32)"
export MCP_DEFAULT_CWD=/root
npm start

The server starts on port 3000 by default.

MCP endpoint: http://127.0.0.1:3000/mcp
Health check: http://127.0.0.1:3000/health

For a real remote ChatGPT connection, you will normally also need:

A public HTTPS domain such as https://mcp.example.com
Nginx or another reverse proxy in front of the Node.js service
OAuth enabled for ChatGPT, or a Bearer token for clients that support one
The MCP URL added in ChatGPT, for example https://mcp.example.com/mcp

The full deployment and ChatGPT connection steps are explained later in this README.

What can it do?

Typical tasks include:

"Show me the current RAM and disk usage."
"Find why Nginx is returning 502."
"Edit this config file and restart the service."
"Clone this Git repository and run its tests."
"Install Node.js packages and build the project."
"Upload a file, verify its hash, and move it into place."

Internally, these actions are provided through 20 MCP tools for shell execution, long-running processes, and filesystem operations.

How it works

With cokacremote:

ChatGPT sends an MCP request over HTTPS.
cokacremote checks authentication.
It runs the requested tool directly on the host server.
The command output or file-operation result is returned to ChatGPT.

The MCP transport is stateless, but long-running command sessions are kept in memory so they can be polled or controlled across multiple requests.

Key features

Shell commands, complete scripts, builds, tests, package installation, Git, and service management
Output polling, stdin delivery, and termination control for long-running processes
Read, write, edit, transfer, and delete host files, including absolute paths
Built-in static Bearer authentication and OAuth 2.1/DCR/PKCE for ChatGPT
Stateless JSON transport per request, per-process output retention, and response size limits
systemd and Nginx deployment examples for Linux VPS/EC2 environments

Available tools

Execution and processes

exec_command: Run shell commands, builds, tests, package installation, Git, service management, and log inspection
run_script: Run complete scripts with Bash, sh, Node.js, Python, or an arbitrary interpreter
write_stdin: Write input to a long-running process and retrieve subsequent output
read_process: Poll output using a cursor and inspect process termination state
terminate_process: Send SIGINT, SIGTERM, or SIGKILL to a managed process group
list_processes: List running or recently completed process sessions

Filesystem

list_directory, stat_path, read_file, write_file
replace_in_file, apply_patch
upload_file, download_file, hash_file
make_directory, copy_path, move_path, remove_path, chmod_path

Relative paths are resolved from MCP_DEFAULT_CWD, while absolute paths and ~/... paths are also allowed. Uploads and downloads use base64 chunk transfer with nextOffset.

The server provides 20 tools in total. remove_path permanently deletes targets without using a trash folder, and apply_patch uses the host's git apply --unsafe-paths.

File reading and transfer rules

offset, bytesRead, and nextOffset returned by read_file are all byte offsets or byte counts.
With encoding="utf8", multibyte characters such as Korean text and emoji are never split across chunk boundaries. bytesRead may exceed the requested maxBytes by up to 3 bytes when necessary to include one complete character, but it never exceeds the server's MCP_MAX_FILE_CHUNK_BYTES limit.
Invalid UTF-8 is rejected instead of silently replacing invalid bytes. Read binary files with encoding="base64".
Base64 input for write_file and upload_file is strictly validated for alphabet, length, and padding. Standard base64 without padding is also accepted, while invalid input is rejected before the file is modified.
write_file.fileMode applies both to new files and when overwriting or appending to existing files.
copy_path returns a conflict error for both files and directories when the destination already exists and force=false.

Transport and state model

/mcp is a stateless Streamable HTTP JSON endpoint where every request is handled independently.

Each POST /mcp request is handled with a new MCP transport and does not issue or require an Mcp-Session-Id.
If an older client sends a stale Mcp-Session-Id header, the server ignores it for request processing.
An authenticated GET /mcp or DELETE /mcp request returning 405 Method Not Allowed is expected. Missing or invalid authentication may produce 401 Unauthorized before the request reaches that method check. The server does not maintain a server-push SSE session.
MCP transport sessions and command process sessionId values are unrelated. A process sessionId returned by exec_command can be reused by later HTTP requests to write_stdin, read_process, and terminate_process.
Running and retained process state is stored in service memory and is lost when the service restarts.

Requirements

Node.js 22 or later and npm
Linux recommended; the provided production deployment examples target systemd and Nginx
Git for apply_patch
OpenSSL for key generation
Python 3 if Python execution through run_script is needed
A stable, publicly accessible HTTPS domain when connecting directly from ChatGPT

Local development

The Quick Start above is enough to run a normal local instance. If you are changing the source code itself, development mode automatically watches the TypeScript entry point:

MCP_AUTH_TOKEN=development-token npm run dev

Authentication

When MCP_AUTH_TOKEN is set, every MCP request requires the following header:

Authorization: Bearer <MCP_AUTH_TOKEN>

You can also enable the built-in OAuth 2.1 Authorization Server for ChatGPT connections. The following values are environment-file examples, not shell commands:

MCP_OAUTH_ENABLED=true
MCP_OAUTH_APPROVAL_KEY=<separate-value-generated-with-openssl-rand-hex-32>
MCP_PUBLIC_URL=https://mcp.example.com
MCP_OAUTH_ISSUER=https://mcp.example.com
MCP_OAUTH_RESOURCE=https://mcp.example.com/mcp
MCP_OAUTH_STATE_FILE=/var/lib/remote-dev-mcp/oauth-state.json

When enabled, the server provides:

RFC 9728 Protected Resource Metadata
RFC 8414 Authorization Server Metadata
Dynamic Client Registration (DCR)
Authorization Code + PKCE (S256)
resource audience validation
Access tokens, replay-detecting refresh token rotation, and grant-level token revocation

OAuth uses a single mcp:tools scope. Enter the MCP_OAUTH_APPROVAL_KEY value on the approval page shown when authorizing a ChatGPT connection. For OAuth-only deployments, it is recommended to leave MCP_AUTH_TOKEN empty so there is no permanent static Bearer bypass path. For backward compatibility, MCP_AUTH_TOKEN is used as the approval key when no dedicated approval key is configured, but keeping the two values separate is safer. Treat both values like root credentials. Registered clients, client secrets, and token hashes are stored in MCP_OAUTH_STATE_FILE with mode 600.

OAuth-related HTTP routes:

Path	Purpose
`/.well-known/oauth-protected-resource`	RFC 9728 resource metadata
`/.well-known/oauth-protected-resource/mcp`	Resource metadata for the `/mcp` path
`/.well-known/oauth-authorization-server`	RFC 8414 authorization server metadata
`/register`	Dynamic Client Registration
`/authorize`	User approval and authorization code issuance
`/token`	Authorization code / refresh token exchange
`/revoke`	Token revocation

If authentication is handled by an OAuth proxy or private network in front of the server, the built-in authentication checks can be disabled:

MCP_AUTH_TOKEN=
MCP_OAUTH_ENABLED=false
MCP_ALLOW_NO_AUTH=true

MCP_ALLOW_NO_AUTH=true does not enable anonymous mode while MCP_AUTH_TOKEN remains set or OAuth is enabled. When using an external IdP or OAuth gateway, bind the Node.js server only to 127.0.0.1 and complete authentication at the upstream layer. Exposing an unauthenticated MCP server to the public internet allows anyone who knows the URL to use the instance with the server process's full privileges.

OpenAI's current remote MCP authentication requirements are documented in MCP server authentication.

VPS/EC2 deployment

The following example installs the server under /opt/remote-dev-mcp on an Ubuntu-based system. The service unit remains named remote-dev-mcp.service for backward compatibility.

sudo mkdir -p /opt/remote-dev-mcp
sudo cp -a package.json package-lock.json tsconfig.json src deploy /opt/remote-dev-mcp/
cd /opt/remote-dev-mcp
sudo npm ci
sudo npm run build
sudo npm prune --omit=dev

sudo install -d -m 0700 /var/lib/remote-dev-mcp

sudo cp deploy/remote-dev-mcp.env.example /etc/remote-dev-mcp.env
sudo chmod 600 /etc/remote-dev-mcp.env
sudo editor /etc/remote-dev-mcp.env

sudo cp deploy/remote-dev-mcp.service /etc/systemd/system/
sudo systemctl daemon-reload
sudo systemctl enable --now remote-dev-mcp
sudo systemctl status remote-dev-mcp

If /usr/bin/node is not the actual Node.js path, update ExecStart in the systemd unit. Use which node to find the correct path.

HTTPS is required when exposing the server to the public internet. Update the domain and certificate paths in the Nginx example, prepare a valid certificate, and then enable the configuration. It is recommended to bind the Node.js server to 127.0.0.1 and expose only ports 80/443 externally. Use a sufficiently long proxy read timeout so long-running tool calls are not terminated by the proxy first.

Set MCP_TRUST_PROXY_HOPS=1 only when exactly one trusted proxy sits in front of the Node.js server, as in the provided Nginx example. Do not reuse that value when exposing the Node.js port directly or when the proxy hop count differs. Incorrectly trusting X-Forwarded-For can allow OAuth rate limits to be bypassed.

At minimum, update the following production environment values for your actual domain:

MCP_HOST=127.0.0.1
MCP_PUBLIC_URL=https://mcp.example.com
MCP_ALLOWED_HOSTS=mcp.example.com,127.0.0.1,localhost
MCP_TRUST_PROXY_HOPS=1
MCP_AUTH_TOKEN=
MCP_OAUTH_ENABLED=true
MCP_OAUTH_APPROVAL_KEY=<value-generated-with-openssl-rand-hex-32>
MCP_OAUTH_ISSUER=https://mcp.example.com
MCP_OAUTH_RESOURCE=https://mcp.example.com/mcp

Connecting ChatGPT

Assume the deployed MCP URL is https://mcp.example.com/mcp.

The UI for adding an MCP server can differ by plan and workspace type. OpenAI's current Plugins Quickstart describes a personal developer-mode flow that enables Settings → Security and login → Developer mode and then adds the MCP server through ChatGPT Plugins. Business/Enterprise/Edu full-MCP app flows may instead use Settings → Apps → Advanced Settings or the administrator path Workspace Settings → Apps → Create.

Enable Developer mode for the account or workspace you are using.
In ChatGPT's Plugins or Apps settings, create a new MCP connection and enter https://mcp.example.com/mcp as the MCP URL.
If an OAuth registration method can be selected, choose Dynamic Client Registration (DCR). Because this server provides DCR, you do not need to create a Client ID and Client Secret manually.
Use the mcp:tools scope. For a public client flow, the token endpoint authentication method can be none.
When the OAuth approval page appears, enter MCP_OAUTH_APPROVAL_KEY to approve the connection.
Complete tool discovery or connection verification, then enable the app/plugin.

This server provides DCR and OAuth Authorization Code + PKCE (S256), but does not provide CIMD or OIDC. ChatGPT continues to support DCR, although CIMD may be preferred when an authorization server provides it. For this server, which provides DCR only, use the DCR flow.

Full MCP write/modify capabilities vary by plan and workspace policy. This server includes destructive tools such as file modification, command execution, and deletion, so not every capability will be available if the connection UI restricts tool permissions.

See the official ChatGPT Plugins Quickstart, OpenAI Help Center guide to Developer mode and MCP apps, and MCP server authentication. When using the OpenAI Responses API, see MCP and Connectors for how to provide the server URL and required authentication information.

Operations and troubleshooting

# Check the Node.js service behind the local proxy
curl http://127.0.0.1:3000/health

# Check the public HTTPS endpoint
curl https://mcp.example.com/health

# Service status and live logs
sudo systemctl status remote-dev-mcp
sudo journalctl -u remote-dev-mcp -f

# Restart after changing configuration or code
sudo systemctl restart remote-dev-mcp

Example healthy response:

{
  "status": "ok",
  "service": "cokacremote",
  "version": "0.1.0",
  "transportMode": "stateless-json",
  "activeMcpSessions": 0,
  "activeMcpRequests": 0,
  "managedProcesses": 0,
  "unrestrictedHostAccess": true,
  "oauthEnabled": true
}

activeMcpSessions is always 0 in stateless mode. This does not mean the connection is broken.
activeMcpRequests is the number of MCP HTTP requests being processed at the time of the health request.
managedProcesses includes both currently running processes and recently completed processes retained temporarily for output retrieval. Check the status field from list_processes to determine whether a process is still running. Completed records are removed after MCP_PROCESS_RETENTION_MS.
Every MCP response includes an X-Request-Id for tracing. Service log entries with event="mcp_request" record the RPC method, tool name, HTTP status, outcome, and duration without logging authentication tokens or tool arguments.

To inspect recent MCP request logs only:

sudo journalctl -u remote-dev-mcp -o cat | grep '"event":"mcp_request"'

Error fetching OAuth configuration: Check MCP_OAUTH_ENABLED, the public URL, and the Nginx proxy for /.well-known/ routes.
401 Unauthorized on MCP requests: Check the Bearer token or OAuth access token.
403 Host header is not allowed: Add the request domain to MCP_ALLOWED_HOSTS.
A command returns a sessionId instead of completing immediately: Poll it with read_process or send input with write_stdin.
MCP requests are independent stateless POST requests. An authenticated GET /mcp or DELETE /mcp returning 405 Method Not Allowed is expected and means the server does not provide a separate SSE stream. Authentication failures may return 401 Unauthorized first.
Service restart behavior: Managed process state and unexchanged authorization codes are lost. OAuth client registrations and issued tokens remain in the state file.

Verification

npm run typecheck
npm test
npm run build

The default tests use a real Streamable HTTP MCP client and cover:

Bearer authentication, stateless request processing, and request tracing headers
Success paths, failure paths, and input boundary cases for all 20 tools
Interactive stdin, output pagination, timeouts, termination, and completed-process retention
UTF-8 character boundaries, strict base64 validation, file modes, and copy/move conflicts
Unified diff validation, application, reverse application, and 3-way application

Full E2E verification against a running external MCP server

From a separate source checkout with development dependencies installed, you can verify all 20 tools against a real HTTPS endpoint:

MCP_E2E_URL='https://mcp.example.com/mcp' \
MCP_E2E_TOKEN='<bearer-token>' \
MCP_E2E_ROOT='/tmp/cokacremote-tools-e2e-manual' \
npx vitest run test/all-tools.integration.test.ts

This verification executes real commands on the target server and creates, modifies, and deletes test files. For safety, MCP_E2E_ROOT must match the /tmp/cokacremote-tools-e2e-* pattern. The test uses only that isolated directory and attempts to clean it afterward. Do not point it at a directory containing production data, and check whether the directory remains after a failed or interrupted test. Running npm ci inside the production installation directory may alter its production-only dependency layout, so run tests from a separate checkout instead.

Key environment variables

Variable	Default	Description
`MCP_HOST`	`0.0.0.0`	HTTP bind address
`MCP_PORT`	`3000`	HTTP port
`MCP_ENDPOINT`	`/mcp`	Streamable HTTP MCP path
`MCP_PUBLIC_URL`	none	External HTTPS base URL excluding `/mcp`
`MCP_ALLOWED_HOSTS`	none	Comma-separated list of allowed Host header hostnames
`MCP_TRUST_PROXY_HOPS`	`0`	Number of trusted reverse-proxy hops; keep `0` when directly exposed
`MCP_AUTH_TOKEN`	none	Optional static Bearer token
`MCP_ALLOW_NO_AUTH`	`false`	Allow startup without authentication
`MCP_OAUTH_ENABLED`	`false`	Enable built-in OAuth 2.1/DCR for ChatGPT
`MCP_OAUTH_APPROVAL_KEY`	`MCP_AUTH_TOKEN`	Dedicated key for the OAuth connection approval page
`MCP_OAUTH_ISSUER`	`MCP_PUBLIC_URL`	OAuth issuer URL
`MCP_OAUTH_RESOURCE`	`<MCP_PUBLIC_URL><MCP_ENDPOINT>`	MCP resource audience
`MCP_OAUTH_STATE_FILE`	inside working directory	Stores registered clients and token hashes
`MCP_OAUTH_ACCESS_TOKEN_TTL_SECONDS`	`3600`	OAuth access token lifetime
`MCP_OAUTH_REFRESH_TOKEN_TTL_SECONDS`	`2592000`	OAuth refresh token lifetime
`MCP_OAUTH_AUTHORIZATION_CODE_TTL_SECONDS`	`300`	One-time authorization code lifetime
`MCP_DEFAULT_CWD`	server startup directory	Base directory for relative paths
`MCP_DEFAULT_SHELL`	`$SHELL` or `/bin/bash`	Default shell for `exec_command`
`MCP_MAX_REQUEST_BODY`	`8mb`	HTTP request body size limit
`MCP_MAX_OUTPUT_BYTES`	`1048576`	Maximum output returned by one tool call
`MCP_MAX_RETAINED_PROCESS_OUTPUT_BYTES`	`4194304`	Retained output per managed process
`MCP_PROCESS_RETENTION_MS`	`3600000`	Retention period for completed processes
`MCP_MAX_PROCESSES`	`128`	Maximum number of retained process sessions
`MCP_MAX_FILE_CHUNK_BYTES`	`1048576`	Maximum file chunk size; UTF-8 reads also stay within this limit
`MCP_MAX_EDIT_FILE_BYTES`	`67108864`	Maximum file size for text replacement

Project layout

Path	Purpose
`src/http-server.ts`	Stateless Streamable HTTP, OAuth routing, and health endpoint
`src/mcp-server.ts`	MCP server metadata and tool registration
`src/exec-tools.ts`	Command, script, and long-running process tools
`src/file-service.ts`	File reading, writing, transfer, and path operations
`src/file-tools.ts`	Filesystem tools and input schemas
`src/oauth.ts`	DCR, PKCE, token issuance/refresh/revocation, and approval UI
`deploy/`	systemd, environment-file, and Nginx examples
`test/all-tools.integration.test.ts`	E2E tests for all 20 tools and external endpoints
`test/`	Configuration, file, process, MCP, and OAuth unit/integration tests

License

MIT License

Disclaimer

THIS SOFTWARE IS PROVIDED “AS IS,” WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, AND NON-INFRINGEMENT.

IN NO EVENT SHALL THE AUTHOR, COPYRIGHT HOLDERS, OR CONTRIBUTORS BE LIABLE FOR ANY CLAIM, DAMAGES, OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT, OR OTHERWISE, ARISING FROM, OUT OF, OR IN CONNECTION WITH THE SOFTWARE OR THE USE OF THE SOFTWARE.

This includes, but is not limited to:

Data loss or corruption
System damage or malfunction
Security breaches or vulnerabilities
Financial loss
Direct, indirect, incidental, special, punitive, or consequential damages

The user assumes full responsibility for all consequences arising from the use of this software, whether such use was intended, authorized, or foreseeable.

ALL RISKS ASSOCIATED WITH USE ARE BORNE BY THE USER

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cokacremote

Quick start

What can it do?

How it works

Key features

Available tools

Execution and processes

Filesystem

File reading and transfer rules

Transport and state model

Requirements

Local development

Authentication

VPS/EC2 deployment

Connecting ChatGPT

Operations and troubleshooting

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Full E2E verification against a running external MCP server

Key environment variables

Project layout

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LICENSE		LICENSE
README.md		README.md
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vitest.config.ts		vitest.config.ts

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cokacremote

Quick start

What can it do?

How it works

Key features

Available tools

Execution and processes

Filesystem

File reading and transfer rules

Transport and state model

Requirements

Local development

Authentication

VPS/EC2 deployment

Connecting ChatGPT

Operations and troubleshooting

Verification

Full E2E verification against a running external MCP server

Key environment variables

Project layout

License

Disclaimer

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