diff --git a/.github/workflows/vscode-extension.yml b/.github/workflows/vscode-extension.yml
new file mode 100644
index 0000000..52f65ee
--- /dev/null
+++ b/.github/workflows/vscode-extension.yml
@@ -0,0 +1,26 @@
+name: VS Code extension
+
+on:
+  push:
+    paths:
+      - "editors/vscode/**"
+      - ".github/workflows/vscode-extension.yml"
+  pull_request:
+    paths:
+      - "editors/vscode/**"
+      - ".github/workflows/vscode-extension.yml"
+
+jobs:
+  compile:
+    name: type-check
+    runs-on: ubuntu-latest
+    defaults:
+      run:
+        working-directory: editors/vscode
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version: "20"
+      - run: npm install
+      - run: npm run compile
diff --git a/editors/vscode/.gitignore b/editors/vscode/.gitignore
new file mode 100644
index 0000000..b78270c
--- /dev/null
+++ b/editors/vscode/.gitignore
@@ -0,0 +1,4 @@
+node_modules/
+out/
+*.vsix
+package-lock.json
diff --git a/editors/vscode/.vscodeignore b/editors/vscode/.vscodeignore
new file mode 100644
index 0000000..7fceb02
--- /dev/null
+++ b/editors/vscode/.vscodeignore
@@ -0,0 +1,7 @@
+# Sources & build config (out/ is shipped, src/ is not).
+.gitignore
+tsconfig.json
+src/**
+**/*.map
+# node_modules is intentionally NOT ignored: vsce ships production dependencies
+# (vscode-languageclient) into the VSIX and prunes devDependencies itself.
diff --git a/editors/vscode/README.md b/editors/vscode/README.md
new file mode 100644
index 0000000..566a735
--- /dev/null
+++ b/editors/vscode/README.md
@@ -0,0 +1,33 @@
+# Hypercode — VS Code extension
+
+Language support for Hypercode `.hc` / `.hcs` files: **live diagnostics** from the
+Hypercode language server (`hypercode lsp`), over the standard Language Server
+Protocol.
+
+It is a thin client — all the language logic lives in the Swift
+[`hypercode`](https://github.com/0al-spec/Hypercode) binary, so the same server
+works in any LSP editor.
+
+## Requirements
+
+The `hypercode` CLI must be installed and support `hypercode lsp`:
+
+```bash
+git clone https://github.com/0al-spec/Hypercode && cd Hypercode
+swift build -c release      # produces .build/release/hypercode
+```
+
+Put `hypercode` on your `PATH`, or set `hypercode.serverPath` to its absolute path.
+
+## Develop
+
+```bash
+cd editors/vscode
+npm install
+npm run compile
+# then press F5 in VS Code to launch the Extension Development Host
+```
+
+## Settings
+
+- `hypercode.serverPath` — path to the `hypercode` executable (default: `hypercode`).
diff --git a/editors/vscode/language-configuration.json b/editors/vscode/language-configuration.json
new file mode 100644
index 0000000..9505602
--- /dev/null
+++ b/editors/vscode/language-configuration.json
@@ -0,0 +1,8 @@
+{
+  "autoClosingPairs": [
+    { "open": "\"", "close": "\"" }
+  ],
+  "surroundingPairs": [
+    ["\"", "\""]
+  ]
+}
diff --git a/editors/vscode/package.json b/editors/vscode/package.json
new file mode 100644
index 0000000..d9251cc
--- /dev/null
+++ b/editors/vscode/package.json
@@ -0,0 +1,52 @@
+{
+  "name": "hypercode",
+  "displayName": "Hypercode",
+  "description": "Hypercode (.hc / .hcs) language support — live diagnostics via the Hypercode language server.",
+  "version": "0.1.0",
+  "publisher": "0al-spec",
+  "license": "MIT",
+  "repository": { "type": "git", "url": "https://github.com/0al-spec/Hypercode" },
+  "engines": { "vscode": "^1.75.0" },
+  "categories": ["Programming Languages", "Linters"],
+  "activationEvents": ["onLanguage:hypercode", "onLanguage:hypercode-hcs"],
+  "main": "./out/extension.js",
+  "contributes": {
+    "languages": [
+      {
+        "id": "hypercode",
+        "aliases": ["Hypercode", "hc"],
+        "extensions": [".hc"],
+        "configuration": "./language-configuration.json"
+      },
+      {
+        "id": "hypercode-hcs",
+        "aliases": ["Hypercode Cascade Sheet", "hcs"],
+        "extensions": [".hcs"],
+        "configuration": "./language-configuration.json"
+      }
+    ],
+    "configuration": {
+      "title": "Hypercode",
+      "properties": {
+        "hypercode.serverPath": {
+          "type": "string",
+          "default": "hypercode",
+          "description": "Path to the `hypercode` executable (it must support `hypercode lsp`). Defaults to `hypercode` on PATH."
+        }
+      }
+    }
+  },
+  "scripts": {
+    "compile": "tsc -p ./",
+    "watch": "tsc -watch -p ./",
+    "vscode:prepublish": "npm run compile"
+  },
+  "dependencies": {
+    "vscode-languageclient": "^9.0.1"
+  },
+  "devDependencies": {
+    "@types/node": "^20.0.0",
+    "@types/vscode": "^1.75.0",
+    "typescript": "^5.4.0"
+  }
+}
diff --git a/editors/vscode/src/extension.ts b/editors/vscode/src/extension.ts
new file mode 100644
index 0000000..b06c89c
--- /dev/null
+++ b/editors/vscode/src/extension.ts
@@ -0,0 +1,40 @@
+import * as vscode from 'vscode';
+import {
+    LanguageClient,
+    LanguageClientOptions,
+    ServerOptions,
+    TransportKind,
+} from 'vscode-languageclient/node';
+
+let client: LanguageClient | undefined;
+
+export function activate(context: vscode.ExtensionContext): void {
+    const serverPath = vscode.workspace
+        .getConfiguration('hypercode')
+        .get<string>('serverPath', 'hypercode');
+
+    // The Hypercode language server is `hypercode lsp` over stdio.
+    const server = { command: serverPath, args: ['lsp'], transport: TransportKind.stdio };
+    const serverOptions: ServerOptions = { run: server, debug: server };
+
+    const clientOptions: LanguageClientOptions = {
+        documentSelector: [
+            { scheme: 'file', language: 'hypercode' },
+            { scheme: 'file', language: 'hypercode-hcs' },
+        ],
+    };
+
+    client = new LanguageClient(
+        'hypercode',
+        'Hypercode Language Server',
+        serverOptions,
+        clientOptions,
+    );
+
+    void client.start();
+    context.subscriptions.push({ dispose: () => { void client?.stop(); } });
+}
+
+export function deactivate(): Thenable<void> | undefined {
+    return client?.stop();
+}
diff --git a/editors/vscode/tsconfig.json b/editors/vscode/tsconfig.json
new file mode 100644
index 0000000..68356ce
--- /dev/null
+++ b/editors/vscode/tsconfig.json
@@ -0,0 +1,15 @@
+{
+  "compilerOptions": {
+    "module": "Node16",
+    "moduleResolution": "Node16",
+    "target": "ES2022",
+    "lib": ["ES2022"],
+    "outDir": "out",
+    "rootDir": "src",
+    "strict": true,
+    "esModuleInterop": true,
+    "skipLibCheck": true,
+    "sourceMap": true
+  },
+  "include": ["src"]
+}
diff --git a/workplan.md b/workplan.md
index 010bc87..07fc62e 100644
--- a/workplan.md
+++ b/workplan.md
@@ -80,7 +80,7 @@ cascade sheets (`.hcs`). Companion to the [RFC](RFC/Hypercode.md) and the
 ## M7 — Diagnostics & LSP (VS Code)
 - [x] HC-100 Structured diagnostics: unified `Diagnostic` (severity, code, source range), LSP-shaped JSON + editor-parseable text, CLI `--diagnostics text|json` — `Sources/Hypercode/Diagnostics/`
 - [x] HC-101 Minimal Swift LSP server (`hypercode lsp`): JSON-RPC over stdio, `initialize`, document sync (didOpen/didChange/didSave/didClose), live `publishDiagnostics` — `Sources/HypercodeCLI/LSPServer.swift` + shared `diagnostics(for:text:)` in the library
-- [ ] HC-102 Thin VS Code extension on `vscode-languageclient` that launches the server
+- [x] HC-102 Thin VS Code extension on `vscode-languageclient` launching `hypercode lsp` — `editors/vscode/` (languages `.hc`/`.hcs`, `hypercode.serverPath` setting); compiled in CI (`.github/workflows/vscode-extension.yml`)
 - [ ] HC-103 Hover / go-to-definition (later, same server)
 
 *(Aim straight for LSP — the standard for VS Code & editor-agnostic. Hyperprompt's custom CLI+JSON-RPC was a documented MVP stopgap; see its ADR-001.)*