MCP setup

In MCP mode your agent takes tickets from Loopback while you work, inside your IDE or CLI, with the subscription you already pay for. See execution modes for when to choose it.

Create a token

In Settings, create an MCP token for one workspace. It starts with lbm_, is shown once and expires; it is revoked as soon as you lose access to the workspace. Keep it in an environment variable, LOOPBACK_MCP_TOKEN in the examples below, never in a file you commit.

Configure your agent

The remote server speaks MCP over Streamable HTTP and authenticates with a bearer token. Set the transport explicitly: some clients fall back to the old SSE transport when it is missing.

The token in your environment

Most clients read the token from LOOPBACK_MCP_TOKEN. Set it in your shell profile, or in the user environment on Windows, then restart the client. Clients that cannot read the environment get the token in their own file: paste it where the placeholder is.

~/.zshrc · ~/.bashrc

export LOOPBACK_MCP_TOKEN='<LOOPBACK_MCP_TOKEN>'

PowerShell

[Environment]::SetEnvironmentVariable("LOOPBACK_MCP_TOKEN", "<LOOPBACK_MCP_TOKEN>", "User")

Claude Code

Run in a terminal

shell

claude mcp add --transport http --scope user loopback https://api.loopback.so/mcp --header 'Authorization: Bearer ${LOOPBACK_MCP_TOKEN}'

In .mcp.json

.mcp.json

{  "mcpServers": {    "loopback": {      "type": "http",      "url": "https://api.loopback.so/mcp",      "headers": {        "Authorization": "Bearer ${LOOPBACK_MCP_TOKEN}"      }    }  }}

Claude Code subscriptions are allowed here: this is MCP mode, inside the official client.

Cursor

In ~/.cursor/mcp.json · .cursor/mcp.json

~/.cursor/mcp.json · .cursor/mcp.json

{  "mcpServers": {    "loopback": {      "url": "https://api.loopback.so/mcp",      "headers": {        "Authorization": "Bearer ${env:LOOPBACK_MCP_TOKEN}"      }    }  }}

Global file; a project can use .cursor/mcp.json.

VS Code (GitHub Copilot)

In .vscode/mcp.json

.vscode/mcp.json

{  "inputs": [    {      "type": "promptString",      "id": "loopback-token",      "description": "Loopback MCP token",      "password": true    }  ],  "servers": {    "loopback": {      "type": "http",      "url": "https://api.loopback.so/mcp",      "headers": {        "Authorization": "Bearer ${input:loopback-token}"      }    }  }}

The key is servers; VS Code asks for the token once and stores it securely.

Windsurf

In ~/.config/devin/mcp_config.json · ~/.codeium/windsurf/mcp_config.json

~/.config/devin/mcp_config.json · ~/.codeium/windsurf/mcp_config.json

{  "mcpServers": {    "loopback": {      "serverUrl": "https://api.loopback.so/mcp",      "headers": {        "Authorization": "Bearer ${env:LOOPBACK_MCP_TOKEN}"      }    }  }}

Older versions read ~/.codeium/windsurf/mcp_config.json.

Zed

In settings.json

settings.json

{  "context_servers": {    "loopback": {      "url": "https://api.loopback.so/mcp",      "headers": {        "Authorization": "Bearer <LOOPBACK_MCP_TOKEN>"      }    }  }}

In the context_servers section of the settings; the token is written literally.

Kiro

In ~/.kiro/settings/mcp.json · .kiro/settings/mcp.json

~/.kiro/settings/mcp.json · .kiro/settings/mcp.json

{  "mcpServers": {    "loopback": {      "url": "https://api.loopback.so/mcp",      "headers": {        "Authorization": "Bearer ${LOOPBACK_MCP_TOKEN}"      },      "autoApprove": [        "loopback_get_ticket",        "loopback_get_logs"      ]    }  }}

The IDE expands only the variables listed in its approved environment variables setting.

Continue

In .continue/mcpServers/loopback.yaml

.continue/mcpServers/loopback.yaml

name: Loopbackversion: 0.0.1schema: v1mcpServers:  - name: loopback    type: streamable-http    url: https://api.loopback.so/mcp    requestOptions:      headers:        Authorization: Bearer ${{ secrets.LOOPBACK_MCP_TOKEN }}

The transport is streamable-http, with a hyphen.

Cline

In cline_mcp_settings.json · ~/.cline/mcp.json

cline_mcp_settings.json · ~/.cline/mcp.json

{  "mcpServers": {    "loopback": {      "type": "streamableHttp",      "url": "https://api.loopback.so/mcp",      "headers": {        "Authorization": "Bearer <LOOPBACK_MCP_TOKEN>"      },      "disabled": false,      "autoApprove": []    }  }}

Without type, Cline uses the old SSE transport.

Antigravity

In ~/.gemini/config/mcp_config.json · .agents/mcp_config.json

~/.gemini/config/mcp_config.json · .agents/mcp_config.json

{  "mcpServers": {    "loopback": {      "serverUrl": "https://api.loopback.so/mcp",      "headers": {        "Authorization": "Bearer <LOOPBACK_MCP_TOKEN>"      }    }  }}

serverUrl is required; url is not supported.

Codex

Run in a terminal

shell

codex mcp add loopback --url https://api.loopback.so/mcp --bearer-token-env-var LOOPBACK_MCP_TOKEN

In ~/.codex/config.toml

~/.codex/config.toml

[mcp_servers.loopback]url = "https://api.loopback.so/mcp"bearer_token_env_var = "LOOPBACK_MCP_TOKEN"default_tools_approval_mode = "approve"

The token is read from the environment variable at run time.

opencode

In ~/.config/opencode/opencode.json · opencode.json

~/.config/opencode/opencode.json · opencode.json

{  "$schema": "https://opencode.ai/config.json",  "mcp": {    "loopback": {      "type": "remote",      "url": "https://api.loopback.so/mcp",      "oauth": false,      "headers": {        "Authorization": "Bearer {env:LOOPBACK_MCP_TOKEN}"      }    }  }}

Without oauth: false, a missing token starts an OAuth discovery.

Tools

The tools Loopback exposes to your agent. Next to them, the agent uses the engine’s tools through its own MCP server: run_pipeline, get_impact_graph, search_logic_flow, verify_done and save_observation.

Tools of the MCP server
Tool	Input	What it does
`loopback_next_ticket`	`workspace_id?, filters?`	MCP mode only: leases the next ticket waiting for your agent and returns the job payload.
`loopback_get_ticket`	`job_id`	The ticket of a job: subject, messages, attachments, widget context and, for proactive tickets, the error group.
`loopback_get_logs`	`job_id, query?`	The log and error events linked to the job.
`loopback_submit_diagnosis`	`job_id, diagnosis`	Submits category, root cause, file and line references, confidence and a public summary without code.
`loopback_submit_draft`	`job_id, body_md, kind?`	Submits the reply draft to the customer, in the language of the ticket.
`loopback_report_fix`	`job_id, branch, head_sha, verify_report, tests, pr_number?`	Reports a fix on a `loopback/` branch with its commit SHA, verification and tests.
`loopback_escalate`	`job_id, reason`	Hands the ticket to a person, with the reason.

A ticket in MCP mode

loopback_next_ticket leases the next job waiting for your agent.
loopback_get_ticket and loopback_get_logs return the ticket, the messages, the widget context and the related log events.
The agent finds the code and submits the diagnosis and, for a question, the reply draft.
For a bug, the agent fixes it on a loopback/ branch, runs the tests and the verification, and pushes the branch.
loopback_report_fix reports branch, commit SHA, verification and tests; Loopback opens the pull request.
loopback_escalate hands the ticket to a person, with the reason.

In MCP mode the verification runs on your machine: its results are marked as reported by the agent, and the API refuses a pull request whose reported verification failed.

Configure your agent

The remote server speaks MCP over Streamable HTTP and authenticates with a bearer token. Set the transport explicitly: some clients fall back to the old SSE transport when it is missing.

The token in your environment

~/.zshrc · ~/.bashrc

export LOOPBACK_MCP_TOKEN='<LOOPBACK_MCP_TOKEN>'

PowerShell

[Environment]::SetEnvironmentVariable("LOOPBACK_MCP_TOKEN", "<LOOPBACK_MCP_TOKEN>", "User")

Claude Code

Run in a terminal

shell

claude mcp add --transport http --scope user loopback https://api.loopback.so/mcp --header 'Authorization: Bearer ${LOOPBACK_MCP_TOKEN}'

In .mcp.json

.mcp.json

{  "mcpServers": {    "loopback": {      "type": "http",      "url": "https://api.loopback.so/mcp",      "headers": {        "Authorization": "Bearer ${LOOPBACK_MCP_TOKEN}"      }    }  }}

Claude Code subscriptions are allowed here: this is MCP mode, inside the official client.

Cursor

In ~/.cursor/mcp.json · .cursor/mcp.json

~/.cursor/mcp.json · .cursor/mcp.json

{  "mcpServers": {    "loopback": {      "url": "https://api.loopback.so/mcp",      "headers": {        "Authorization": "Bearer ${env:LOOPBACK_MCP_TOKEN}"      }    }  }}

Global file; a project can use .cursor/mcp.json.

VS Code (GitHub Copilot)

In .vscode/mcp.json

.vscode/mcp.json

{  "inputs": [    {      "type": "promptString",      "id": "loopback-token",      "description": "Loopback MCP token",      "password": true    }  ],  "servers": {    "loopback": {      "type": "http",      "url": "https://api.loopback.so/mcp",      "headers": {        "Authorization": "Bearer ${input:loopback-token}"      }    }  }}

The key is servers; VS Code asks for the token once and stores it securely.

Windsurf

In ~/.config/devin/mcp_config.json · ~/.codeium/windsurf/mcp_config.json

~/.config/devin/mcp_config.json · ~/.codeium/windsurf/mcp_config.json

{  "mcpServers": {    "loopback": {      "serverUrl": "https://api.loopback.so/mcp",      "headers": {        "Authorization": "Bearer ${env:LOOPBACK_MCP_TOKEN}"      }    }  }}

Older versions read ~/.codeium/windsurf/mcp_config.json.

Zed

In settings.json

settings.json

{  "context_servers": {    "loopback": {      "url": "https://api.loopback.so/mcp",      "headers": {        "Authorization": "Bearer <LOOPBACK_MCP_TOKEN>"      }    }  }}

In the context_servers section of the settings; the token is written literally.

Kiro

In ~/.kiro/settings/mcp.json · .kiro/settings/mcp.json

~/.kiro/settings/mcp.json · .kiro/settings/mcp.json

{  "mcpServers": {    "loopback": {      "url": "https://api.loopback.so/mcp",      "headers": {        "Authorization": "Bearer ${LOOPBACK_MCP_TOKEN}"      },      "autoApprove": [        "loopback_get_ticket",        "loopback_get_logs"      ]    }  }}

The IDE expands only the variables listed in its approved environment variables setting.

Continue

In .continue/mcpServers/loopback.yaml

.continue/mcpServers/loopback.yaml

name: Loopbackversion: 0.0.1schema: v1mcpServers:  - name: loopback    type: streamable-http    url: https://api.loopback.so/mcp    requestOptions:      headers:        Authorization: Bearer ${{ secrets.LOOPBACK_MCP_TOKEN }}

The transport is streamable-http, with a hyphen.

Cline

In cline_mcp_settings.json · ~/.cline/mcp.json

cline_mcp_settings.json · ~/.cline/mcp.json

{  "mcpServers": {    "loopback": {      "type": "streamableHttp",      "url": "https://api.loopback.so/mcp",      "headers": {        "Authorization": "Bearer <LOOPBACK_MCP_TOKEN>"      },      "disabled": false,      "autoApprove": []    }  }}

Without type, Cline uses the old SSE transport.

Antigravity

In ~/.gemini/config/mcp_config.json · .agents/mcp_config.json

~/.gemini/config/mcp_config.json · .agents/mcp_config.json

{  "mcpServers": {    "loopback": {      "serverUrl": "https://api.loopback.so/mcp",      "headers": {        "Authorization": "Bearer <LOOPBACK_MCP_TOKEN>"      }    }  }}

serverUrl is required; url is not supported.

Codex

Run in a terminal

shell

codex mcp add loopback --url https://api.loopback.so/mcp --bearer-token-env-var LOOPBACK_MCP_TOKEN

In ~/.codex/config.toml

~/.codex/config.toml

[mcp_servers.loopback]url = "https://api.loopback.so/mcp"bearer_token_env_var = "LOOPBACK_MCP_TOKEN"default_tools_approval_mode = "approve"

The token is read from the environment variable at run time.

opencode

In ~/.config/opencode/opencode.json · opencode.json

~/.config/opencode/opencode.json · opencode.json

{  "$schema": "https://opencode.ai/config.json",  "mcp": {    "loopback": {      "type": "remote",      "url": "https://api.loopback.so/mcp",      "oauth": false,      "headers": {        "Authorization": "Bearer {env:LOOPBACK_MCP_TOKEN}"      }    }  }}

Without oauth: false, a missing token starts an OAuth discovery.

Tools

Tools of the MCP server
Tool	Input	What it does
`loopback_next_ticket`	`workspace_id?, filters?`	MCP mode only: leases the next ticket waiting for your agent and returns the job payload.
`loopback_get_ticket`	`job_id`	The ticket of a job: subject, messages, attachments, widget context and, for proactive tickets, the error group.
`loopback_get_logs`	`job_id, query?`	The log and error events linked to the job.
`loopback_submit_diagnosis`	`job_id, diagnosis`	Submits category, root cause, file and line references, confidence and a public summary without code.
`loopback_submit_draft`	`job_id, body_md, kind?`	Submits the reply draft to the customer, in the language of the ticket.
`loopback_report_fix`	`job_id, branch, head_sha, verify_report, tests, pr_number?`	Reports a fix on a `loopback/` branch with its commit SHA, verification and tests.
`loopback_escalate`	`job_id, reason`	Hands the ticket to a person, with the reason.

A ticket in MCP mode

loopback_next_ticket leases the next job waiting for your agent.

loopback_get_ticket and loopback_get_logs return the ticket, the messages, the widget context and the related log events.

The agent finds the code and submits the diagnosis and, for a question, the reply draft.

For a bug, the agent fixes it on a loopback/ branch, runs the tests and the verification, and pushes the branch.

loopback_report_fix reports branch, commit SHA, verification and tests; Loopback opens the pull request.

loopback_escalate hands the ticket to a person, with the reason.

In MCP mode the verification runs on your machine: its results are marked as reported by the agent, and the API refuses a pull request whose reported verification failed.