Use Fulcrum in VS Code

Install the extension (preview)

The extension is at v0.1 — not yet published to the Marketplace, so you install the .vsixby hand. It's a single download, no auth, hosted alongside the CLI binaries on the public S3 bucket.

curl -L -o fulcrum-code-vscode.vsix \
  https://releases.fulcrumcode.app/latest/fulcrum-code-vscode.vsix
code --install-extension fulcrum-code-vscode.vsix

Or grab the file directly: fulcrum-code-vscode.vsix and drop it into VS Code's Extensions pane (the three-dot menu → "Install from VSIX…"). Restart VS Code; the Fulcrum activity-bar icon appears on the left rail.

The extension still requires the CLI binary to be installed (it shells out to it under the hood). If you don't have fulcrum on $PATH, see the install guide first.

Or just use the integrated terminal

Equally legitimate — most heavy CLI users (us included) do this. Launch Fulcrum from VS Code's integrated terminal at the project root.

# Open the integrated terminal: Cmd+J (macOS) / Ctrl+` (Linux/Windows)
cd /path/to/your/project
fulcrum

On first run, Fulcrum prompts you to /login(PKCE flow in the browser), then picks up the project's CLAUDE.md or AGENTS.mdif present. From there you're chatting.

Recommended layout

A two-pane setup keeps code and agent side by side without either one stealing focus.

• Left pane — your normal VS Code editor workspace.
• Right pane — the integrated terminal running fulcrum.
• VS Code's split editor (Cmd+\) puts code on the left and a terminal-only group on the right. Drag the terminal panel out of the bottom strip and into the right group.
• When Fulcrum edits a file, VS Code's file watcher picks it up immediately and shows the diff inline. You don't need to refresh.

Project memory and the VS Code workspace

Drop a CLAUDE.md (or AGENTS.md) at the repo root. VS Code shows it in the file tree alongside everything else; Fulcrum reads it on session start whenever you launch from that directory.

For multi-root workspaces, each root can have its own CLAUDE.md — Fulcrum loads whichever applies based on the current working directory at launch.

Keep CLAUDE.md in version control. Both VS Code collaborators and Fulcrum benefit — your team gets shared context for free. See Memory & knowledge for the full layering story.

Shell integration

Fulcrum prints clickable file references (e.g. src/auth.ts:42). VS Code's integrated terminal makes those Cmd-clickable, so you can jump from a Fulcrum reply straight to the line in the editor without retyping a path.

For zsh and bash users, shell integration is on by default in modern VS Code releases; for fish, enable it via terminal.integrated.shellIntegration.enabled in settings.

Useful VS Code settings

A handful of settings make long Fulcrum sessions less painful. Drop these into your workspace or user settings.json:

// .vscode/settings.json
{
  // Bigger scrollback so long Fulcrum sessions don't lose history
  "terminal.integrated.scrollback": 50000,
  // The TUI uses your terminal's font — pick a mono with good
  // box-drawing support so the spinner glyphs render cleanly
  "terminal.integrated.fontFamily": "JetBrainsMono Nerd Font, JetBrains Mono, Menlo",
  "terminal.integrated.fontSize": 13,
  // Don't auto-close on Fulcrum exit so you can re-launch fast
  "terminal.integrated.confirmOnExit": "never"
}

Tasks integration (optional, advanced)

You can wire fulcrum exec into a VS Code task and bind it to a keybinding for one-shot prompts on the file or selection you have open.

// .vscode/tasks.json
{
  "version": "2.0.0",
  "tasks": [
    {
      "label": "Fulcrum: explain selection",
      "type": "shell",
      "command": "fulcrum exec \"${file}:${lineNumber}: explain this code: $(cat ${file})\"",
      "problemMatcher": []
    }
  ]
}

Bind it via keybindings.json so a single shortcut runs Fulcrum on whatever you have selected. This is a starting point — adjust the command to suit. For most cases ${selectedText} is more reliable than ${file}.

Profiles and multi-project

If you work across multiple repos, VS Code workspaces let you keep distinct integrated-terminal layouts per project. Fulcrum's project memory (CLAUDE.md) handles the rest — each repo gets its own context automatically based on the directory you launch from.

What the extension does and doesn't do today

The extension is at v0.1 — small and deliberate. What ships:

• Activity-bar entry. Side panel for quick sessions without leaving the editor.
• Send selection. Highlight code, fire it at Fulcrum with a keybinding.
• Shells out to the CLI. Same engine, same login, same memory — the extension is a thin host around fulcrum exec.

What's NOT in v0.1 yet:

• No inline diff review. Fulcrum edits files directly; VS Code's git diff picks them up after the fact, but no in-editor accept/reject UI.
• No Marketplace listing. Install via the .vsix download above. Marketplace publishing is planned but gated on the publisher account verification.
• No multi-file PR view. Use git or gh from the terminal alongside Fulcrum.

If you want the full feature set today (sub-agents, voice, auto-approve toggle, /cost, /context, etc.), the integrated terminal is still the more complete surface.

One-shot mode

fulcrum execis great inside VS Code's terminal for quick questions that don't need a full session. It accepts piped input, so you can hand it a diff or a log directly:

git diff main | fulcrum exec "review these changes for security issues"
cat error.log | fulcrum exec "what's the root cause?"

Tips

• Open Fulcrum in a dedicated terminal tab — switching tabs preserves the session.
• Ctrl+L clears the transcript without ending the session.
• /cancel aborts the current turn — useful if Fulcrum heads down a wrong path.
• Use /cost periodically to keep an eye on token spend across a long session.

Next steps

• Prompting → Writing prompts that get the most out of a terminal-based session.
• Tools → The tool surface Fulcrum has access to during a session.
• Best practices → How to structure work so the agent stays on track.