> ## Documentation Index
> Fetch the complete documentation index at: https://usefused.com/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# Connect MCP servers

> Connect HTTP endpoints or provision MCP servers with Fused from Studio.

Choose **Connect tools** or open **MCP connections** in the workspace sidebar. Choose **Add HTTP MCP endpoint** to connect an existing Streamable HTTP server, or enter your Fused URL and choose **Connect Fused**. Complete sign-in in the same browser, then reopen the dialog. Management credentials remain in Studio's server memory; restarting Studio requires reconnecting.

After connecting, choose **Add existing Fused MCP** to select an active server version, or **Create MCP with Fused** to select services and their operations. Choose the owning agent, the Fused bucket, and an optional owner team. An empty operation selection is rejected; **All operations** must be selected explicitly. Provider connections and bucket permissions must already be configured in Fused.

**Review connection** shows the exact provisioning configuration and source diffs. **Apply connection** can create a server, issue a seven-day execution token, and write the owning agent's MCP Client. It also adds runtime environment references to an existing `harnest-deployment.yaml`; select a deployment agent name if that manifest contains multiple agents. Studio checks source revisions before provisioning. If the remote result is uncertain, check Fused's server list before preparing another review; Studio does not replay that mutation automatically.

Runtime credentials are stored outside project source in owner-only files under `~/.harnest/studio-credentials`. Set `HARNEST_BUILDER_CREDENTIALS_DIR` before starting Studio to choose another private directory. Studio supplies these bindings only to commands for that project and redacts execution tokens from command output. Restart an already-running agent after applying a connection. For commands launched outside Studio or deployments managed elsewhere, provide the variables shown in the review through your own secret manager. Disconnecting Fused clears management access and pending reviews; it does not revoke existing MCP execution tokens.

To let **Build agent** discover Fused operations, enable **Allow Fused service and operation metadata to be shared with the model**. This separate permission is off by default. The model can propose a plan but cannot access credentials or apply it.


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