Kin - Semantic VCS for VS Code

Semantic code intelligence powered by Kin's graph engine.

MCP-first with CLI fallback. All graph queries route through a persistent MCP connection for zero-overhead access to the in-memory graph. If the MCP connection is unavailable, each query transparently falls back to a CLI subprocess call. The graph is the authority; the editor is a projection surface.

Features

• Entity Explorer -- Browse functions, classes, modules, and other entities in a sidebar tree view grouped by kind.
• Semantic Search -- Cmd+Shift+K S to find entities by name with quick navigation to source.
• Entity Trace -- Right-click in the editor or Cmd+Shift+K T to trace an entity through the dependency graph.
• Hover Info -- Hover over any symbol to see its entity kind, file, and signature from the graph.
• Go to Definition -- F12 / Ctrl+Click resolves definitions through the Kin graph.
• Workspace Symbols -- Cmd+T / Ctrl+T searches entities via the graph-backed symbol provider.
• Semantic Review -- Cmd+Shift+K V to run entity-level code review with gutter decorations and diagnostics.
• Semantic Rename -- F2 on any entity for graph-aware rename across all references.
• Status Bar -- Live entity count and connection mode (MCP/CLI) in the bottom bar. Click for a graph overview.
• Graph Overview -- Cmd+Shift+K O to see entity counts, edge counts, and kind breakdowns at a glance.

Accessibility

• Entity Explorer tree items include explicit kind, file, line, and signature context for screen readers.
• Search and trace quick-picks keep the entity name separate from the file location and kind details.
• Review gutter markers use theme-driven icons and colors so they stay legible in high-contrast themes.
• Command Palette entries are grouped under the Kin category for easier discovery.

Requirements

• The kin CLI binary must be installed (~/.kin/bin/kin or on PATH).
• A Kin-initialized repository (.kin/ directory in workspace root).

Installation

1. Build the extension: npm install && npm run compile
2. Package: npm run package:vsix
3. Install the .vsix file in VS Code: Extensions > "..." > "Install from VSIX..."

Or for development: open this folder in VS Code and press F5 to launch the Extension Development Host.

Compatibility

• VSIX install smoke verified on 2026-03-25 in VSCodium 1.112.01907, Cursor 2.6.21, and Windsurf 1.108.2.
• Each editor listed the installed extension as firelock.kin@0.1.0 from the packaged VSIX.
• Tagged GitHub releases now attach a packaged VSIX for alpha, beta / rc, and stable lanes.
• Visual Studio Marketplace publication is optional and runs only when VSCE_TOKEN is configured; until then, GitHub release assets remain the canonical install path.

Configuration

Setting	Default	Description
kin.binaryPath	""	Path to the kin binary. Empty = auto-detect (~/.kin/bin/kin or PATH).
kin.autoStart	true	Auto-activate when .kin/ exists in workspace.
kin.mcpEnabled	true	Use a persistent MCP connection for zero-overhead graph queries. Disable to fall back to CLI subprocess per command.

Commands

Command	Keybinding	Description
Kin: Semantic Search	Cmd+Shift+K S	Search entities by name
Kin: Graph Overview	Cmd+Shift+K O	Show graph statistics
Kin: Trace Entity	Cmd+Shift+K T	Trace entity through the graph
Kin: Review Current File	Cmd+Shift+K V	Semantic code review with gutter decorations
Kin: Refresh Entity Explorer	Cmd+Shift+K R	Re-index the entity tree
Kin: Initialize Repository	--	Run kin init in the workspace
Kin: Show Status	--	Show entity count and connection mode

On Linux/Windows, replace Cmd with Ctrl.

Architecture

The extension uses an MCP-first architecture with CLI fallback. On activation, it spawns a persistent MCP connection to kin mcp start over stdio (JSON-RPC 2.0 with Content-Length framing). All graph queries -- search, trace, overview, status, review -- route through MCP for zero-overhead access to the in-memory graph. If the MCP connection is unavailable, each query transparently falls back to a CLI subprocess call (execFile).

Key components:

• McpClient (mcp-client.ts) -- Manages the MCP process lifecycle, auto-reconnects on crash, and handles the initialize handshake.
• KinClient (kin-client.ts) -- Unified query interface that tries MCP first, then falls back to CLI. All commands consume this.
• WorkspaceManager (workspace-manager.ts) -- Multi-root workspace support with per-folder MCP connections.
• Language Providers -- HoverProvider, DefinitionProvider, WorkspaceSymbolProvider, and RenameProvider hook into VS Code's native APIs backed by the Kin graph.

The kin.mcpEnabled setting controls whether MCP is used. When disabled, all queries go through CLI subprocesses (5-50ms overhead per command).

License

Apache-2.0. Copyright 2026 Firelock LLC.