Connect MCP accounts

Reuse a declared CLI server login or configure client credentials for the built-in harness.

Choose a form

Set oauth on a declared HTTP MCP server to use a saved login or client credentials. This option replaces bearerTokenVariable and any Authorization header; choose the form supported by your harness.

Form	Harnesses	Token source
`oauth: "login"`	Claude Code, Codex, Kimi Code	The CLI’s own MCP login, made once on the host
`oauth: { client… }`	Built-in harness	A client credentials grant requested in the sandbox
Neither	Copilot CLI, Antigravity	Use `bearerTokenVariable` with a token you provide

A harness that cannot use the declared form fails when the agent is composed.

Then declare oauth: "login".

import { createAgent, createCodexHarness } from "@elie-laloum/outpost";

const coder = createAgent({
  harness: createCodexHarness({
    authentication: "account",
    mcpServers: {
      linear: { url: "https://mcp.linear.app/mcp", oauth: "login" },
    },
  }),
});

CLI	Host login	Host file (relocated by)
Claude Code	`claude mcp add --transport http linear https://mcp.linear.app/mcp`, then `claude mcp login linear`	`~/.claude/.credentials.json` (`CLAUDE_CONFIG_DIR`)
Codex	Set `mcp_oauth_credentials_store = "file"` in `~/.codex/config.toml`, then `codex mcp login linear`	`~/.codex/.credentials.json` (`CODEX_HOME`)
Kimi Code	Add the server to `~/.kimi-code/mcp.json`, then authenticate it in a `kimi` session	`~/.kimi-code/credentials/mcp/` (`KIMI_CODE_HOME`)

Before the agent starts, Outpost copies only the matching server entries into the private sandbox home. Your other logins, including the CLI account itself, are not copied by this option. A missing login fails with the host command to run.

With createLocalSandboxProvider(), nothing is copied: the CLI reads your home directly.

Request tokens with client credentials

For machine-to-machine servers in the built-in harness, name the variables that hold the client ID and secret.

import type { McpServers } from "@elie-laloum/outpost";

const mcpServers: McpServers = {
  internal: {
    url: "https://mcp.example.com/mcp",
    oauth: {
      clientIdVariable: "MCP_CLIENT_ID",
      clientSecretVariable: "MCP_CLIENT_SECRET",
      scopes: ["mcp:read"],
    },
  },
};
// createHarness({ modelProvider, mcpServers })

Declare both variables on the sandbox provider or in .outpost/.env (Environment variables). Without scopes, the bridge requests the scope named in the server’s 401 challenge, if any.

The HTTP bridge in the sandbox obtains the token itself, so the secret stays there and outbound rules apply to the token requests.

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100 %

DiscoverFrom the MCP server URL.
1. Read the metadataProtected resource metadata, then the authorization server metadata and its token endpoint. sandbox
(Steps)
- → Request : then
RequestOne client_credentials grant.
1. Authenticate the clientWith client_secret_basic, or client_secret_post when the server advertises only that. sandbox
2. Bind the tokenThe server URL is sent as resource. sandbox
(Steps)
- → Reuse : then
ReuseUntil the token expires.
1. Retry on 401Discover again, request a new token and retry the request once. sandbox
(Steps)

Limits

oauth is for HTTP servers only and cannot be combined with bearerTokenVariable or an Authorization header.
The built-in harness refuses "login"; CLI harnesses refuse client credentials.
Client credentials support neither private_key_jwt, refresh tokens nor interactive authorization.
Outpost never reads a system keychain: a CLI that stores its MCP login there has nothing to copy.

API: McpHttpServer · McpClientCredentials · McpServers.

Choose a form

Reuse a CLI login

Request tokens with client credentials

Limits