MCP servers

Fixes for MCP packages that give an agent tools, such as Slack, Atlassian, Linear, and Datadog. If you want an outside agent to connect to Marshal itself, see Connecting an AI Agent (MCP).

Most MCP packages sign in with OAuth. The credential stays with Marshal and is never shown to the agent. To see what each MCP package covers, see the package catalog.

Connect fails: unknown or unconfigured provider

You see: unknown or unconfigured provider "<name>" after you press Connect.

Cause: Marshal has no sign-in set up for that provider on your install.

Fix: An admin opens Settings, OAuth Apps and checks the provider. It connects through Marshal’s shared app, through dynamic registration, or through your own app. If the provider has no row, the admin selects Register a provider key not listed here and enters the Client ID and Client secret from the provider. Then connect again.

Connect fails: the provider refused to register Marshal

You see: the authorization server refused to register this deployment as a client; this integration cannot be connected until the provider approves it

Cause: The provider signs in new clients through dynamic registration, and it refused your Marshal install.

Fix: An admin registers an app with the provider, then opens Settings, OAuth Apps, selects Own app on the provider’s row and enters the app’s details. Some providers also need an admin on their side to allow new clients. Then connect again.

An MCP connection needs to be reconnected

You see: The connection shows Needs reconnect on the Connections page, and This connection needs to be reconnected before an agent can use it.

Cause: The sign-in with the provider ended or was revoked.

Fix: Reconnect it on the Connections page. See A connection needs to be reconnected.

A stdio MCP server stops with an npm registry error

You see: A tool call to a custom MCP server that runs with stdio (npx) fails with mcp upstream error: followed by the cause, for example the npm registry rejected the credentials (401/403); check the registry and its credential or the package was not found in the configured npm registry (404); check the package name and the registry mapped to its scope.

Cause: The server installs its npm package when it starts, and the registry refused, could not find the package or version, or could not be reached. The message names which one. It never repeats URLs or tokens.

Fix: An admin opens Settings > npm Registries and checks the registry that serves the package’s scope: its URL and its credential. Check the package name and version in the server’s settings. Then call the tool again.

See Atlassian: consent screen or redirect fails.

Slack messages are sent as me

Cause: The Slack package connects your own Slack identity. Slack accepts only a user token for its MCP server, so the agent acts as you, not as an organization bot.

Fix: Each person connects their own Slack account, and the agent posts as the person whose account it uses.

An MCP package will not install alone

Cause: Some MCP packages build on another package. github-mcp needs the github package. playwright-mcp and chrome-devtools-mcp need chromium.

Fix: Install the required package first, then the MCP package.