Integration

Thruline + Windsurf

Windsurf (formerly Codeium) ships its agentic IDE around the Cascade agent, with full Model Context Protocol support. Wire Thruline into Cascade and the agent picks up your repo's architectural domains, conventions, and co-change patterns automatically — the same way it would discover any other MCP tool.

What you get

Cascade gets architectural awareness. Before generating or editing code, Cascade can ask Thruline what domain a file belongs to, what conventions apply, and what historically changes alongside it.
Pre-commit changeset checks. Run thruline_review_changeset on staged files to catch missing co-changes before pushing.
Lower token spend. Cascade stops aimlessly grepping for context. One Thruline tool call replaces ten file reads.
No platform lock-in. The same Thruline that powers Cascade also powers Claude Code, Cursor, VS Code, and Zed.

Setup

1. Add the MCP server

Open Windsurf's MCP config file at:

macOS / Linux: ~/.codeium/windsurf/mcp_config.json
Windows: %USERPROFILE%\.codeium\windsurf\mcp_config.json

Create the file if it doesn't exist (Windsurf doesn't create one on first launch). Add the Thruline entry:

{
  "mcpServers": {
    "thruline": {
      "serverUrl": "https://mcp.thrulinecontext.com/mcp"
    }
  }
}

You can also add Thruline through Windsurf Settings › Cascade › MCP Servers, which writes to the same file.

2. Reload Cascade

Cascade picks up new MCP servers on the next chat session. Either start a new conversation or restart Windsurf.

3. Authenticate

The first time Cascade calls a Thruline tool, you'll be prompted to authenticate via GitHub OAuth. Sign in with the GitHub account you used for Thruline.

4. Index your repository

Ask Cascade to index:

"Index this repo with Thruline — it's owner/repo-name."

Indexing takes 1–3 minutes. After that it stays current incrementally.

Tools available to Cascade

Tool	Purpose
`thruline_index`	Index a repository for the first time, or re-index after major changes
`thruline_review`	Get domain, conventions, connected files, and git history for a specific file
`thruline_review_changeset`	Check changed files for missing co-changes and convention violations
`thruline_get_domains`	List all architectural domains discovered in the repository
`thruline_get_segments`	List code segments with their conventions and file summaries
`thruline_get_network`	Get the domain connection graph showing how areas of the codebase relate
`thruline_get_findings`	Retrieve commit and domain activity for a repository
`thruline_report_findings`	Report findings so Thruline can refine its connection weights

Notes for Windsurf specifically

Cascade picks tools opportunistically

Cascade reads the MCP tool descriptions Thruline publishes and decides when to call them. You don't need to prompt for specific tools, but you can nudge it: "Run thruline_review on this file before editing it."

Streamable HTTP transport

Windsurf supports stdio and Streamable HTTP transports for MCP servers. Thruline uses HTTP, which means no local process to install — Cascade just connects to thrulinecontext.com.

One config file, every project

The Windsurf MCP config is global, not per-project. Add Thruline once and Cascade has access to it across every repo you open. Indexing happens per-repo, so each project still needs its own initial thruline_index call.

Troubleshooting

Tools not appearing in Cascade — check that ~/.codeium/windsurf/mcp_config.json exists, is valid JSON, and that you've started a new chat session since editing it.
Authentication never completes — check your default browser is reachable. If OAuth is stuck, open your Thruline dashboard, log out, and reconnect from Cascade.
Repository not indexed — ask Cascade to call thruline_index with your repo name in owner/repo format.

Give Cascade real codebase context.