openclaw · steipete · May 27, 2026 · May 27, 2026 · May 27, 2026 · May 27, 2026
diff --git a/.github/labeler.yml b/.github/labeler.yml
@@ -496,6 +496,7 @@
   - changed-files:
       - any-glob-to-any-file:
           - "extensions/diffs/**"
+          - "extensions/diffs-language-pack/**"
 "extensions: elevenlabs":
   - changed-files:
       - any-glob-to-any-file:

@@ -249,6 +249,7 @@ extensions/qa-lab/web/dist/
 # Generated bundled plugin runtime dependency manifests
 extensions/**/.openclaw-runtime-deps.json
 extensions/**/.openclaw-runtime-deps-stamp.json
+extensions/diffs-language-pack/assets/viewer-runtime.js
 
 # Output dir for scripts/run-opengrep.sh (local opengrep scans)
 /.opengrep-out/

diff --git a/.oxlintrc.json b/.oxlintrc.json
@@ -182,6 +182,7 @@
     "dist-runtime/",
     "docs/_layouts/",
     "extensions/diffs/assets/viewer-runtime.js",
+    "extensions/diffs-language-pack/assets/viewer-runtime.js",
     "node_modules/",
     "patches/",
     "pnpm-lock.yaml",

diff --git a/docs/plugins/manifest.md b/docs/plugins/manifest.md
@@ -149,6 +149,7 @@ or npm install metadata. Those belong in your plugin code and `package.json`.
 | ------------------------------------ | -------- | -------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
 | `id`                                 | Yes      | `string`                         | Canonical plugin id. This is the id used in `plugins.entries.<id>`.                                                                                                                                                                             |
 | `configSchema`                       | Yes      | `object`                         | Inline JSON Schema for this plugin's config.                                                                                                                                                                                                    |
+| `requiresPlugins`                    | No       | `string[]`                       | Plugin ids that must also be installed for this plugin to have an effect. Discovery keeps the plugin loadable but warns when any required plugin is missing.                                                                                    |
 | `enabledByDefault`                   | No       | `true`                           | Marks a bundled plugin as enabled by default. Omit it, or set any non-`true` value, to leave the plugin disabled by default.                                                                                                                    |
 | `enabledByDefaultOnPlatforms`        | No       | `string[]`                       | Marks a bundled plugin as enabled by default only on the listed Node.js platforms, for example `["darwin"]`. Explicit config still wins.                                                                                                        |
 | `legacyPluginIds`                    | No       | `string[]`                       | Legacy ids that normalize to this canonical plugin id.                                                                                                                                                                                          |

diff --git a/docs/plugins/plugin-inventory.md b/docs/plugins/plugin-inventory.md
@@ -151,6 +151,7 @@ commands.
 | [diagnostics-otel](/plugins/reference/diagnostics-otel)             | OpenClaw diagnostics OpenTelemetry exporter.                                                                        | `@openclaw/diagnostics-otel`<br />npm; ClawHub: `clawhub:@openclaw/diagnostics-otel`             | plugin                                                                       |
 | [diagnostics-prometheus](/plugins/reference/diagnostics-prometheus) | OpenClaw diagnostics Prometheus exporter.                                                                           | `@openclaw/diagnostics-prometheus`<br />npm; ClawHub: `clawhub:@openclaw/diagnostics-prometheus` | plugin                                                                       |
 | [diffs](/plugins/reference/diffs)                                   | Read-only diff viewer and file renderer for agents.                                                                 | `@openclaw/diffs`<br />npm; ClawHub                                                              | contracts: tools; skills                                                     |
+| [diffs-language-pack](/plugins/reference/diffs-language-pack)       | Adds syntax highlighting for languages outside the default diffs viewer set.                                        | `@openclaw/diffs-language-pack`<br />npm; ClawHub: `clawhub:@openclaw/diffs-language-pack`       | plugin                                                                       |
 | [discord](/plugins/reference/discord)                               | Adds the Discord channel surface for sending and receiving OpenClaw messages.                                       | `@openclaw/discord`<br />npm; ClawHub                                                            | channels: discord; contracts: transcriptSourceProviders                      |
 | [feishu](/plugins/reference/feishu)                                 | Adds the Feishu channel surface for sending and receiving OpenClaw messages.                                        | `@openclaw/feishu`<br />npm; ClawHub                                                             | channels: feishu; contracts: tools; skills                                   |
 | [google-meet](/plugins/reference/google-meet)                       | Join Google Meet calls through Chrome or Twilio transports.                                                         | `@openclaw/google-meet`<br />npm; ClawHub                                                        | contracts: tools                                                             |

diff --git a/docs/plugins/reference.md b/docs/plugins/reference.md
@@ -44,6 +44,7 @@ pnpm plugins:inventory:gen
 | [diagnostics-otel](/plugins/reference/diagnostics-otel)             | OpenClaw diagnostics OpenTelemetry exporter.                                                                                                                         | `@openclaw/diagnostics-otel`<br />npm; ClawHub: `clawhub:@openclaw/diagnostics-otel`             | plugin                                                                                                                                                                                                                                                           |
 | [diagnostics-prometheus](/plugins/reference/diagnostics-prometheus) | OpenClaw diagnostics Prometheus exporter.                                                                                                                            | `@openclaw/diagnostics-prometheus`<br />npm; ClawHub: `clawhub:@openclaw/diagnostics-prometheus` | plugin                                                                                                                                                                                                                                                           |
 | [diffs](/plugins/reference/diffs)                                   | Read-only diff viewer and file renderer for agents.                                                                                                                  | `@openclaw/diffs`<br />npm; ClawHub                                                              | contracts: tools; skills                                                                                                                                                                                                                                         |
+| [diffs-language-pack](/plugins/reference/diffs-language-pack)       | Adds syntax highlighting for languages outside the default diffs viewer set.                                                                                         | `@openclaw/diffs-language-pack`<br />npm; ClawHub: `clawhub:@openclaw/diffs-language-pack`       | plugin                                                                                                                                                                                                                                                           |
 | [discord](/plugins/reference/discord)                               | Adds the Discord channel surface for sending and receiving OpenClaw messages.                                                                                        | `@openclaw/discord`<br />npm; ClawHub                                                            | channels: discord; contracts: transcriptSourceProviders                                                                                                                                                                                                          |
 | [document-extract](/plugins/reference/document-extract)             | Extract text and fallback page images from local document attachments.                                                                                               | `@openclaw/document-extract-plugin`<br />included in OpenClaw                                    | contracts: documentExtractors                                                                                                                                                                                                                                    |
 | [duckduckgo](/plugins/reference/duckduckgo)                         | Adds web search provider support.                                                                                                                                    | `@openclaw/duckduckgo-plugin`<br />included in OpenClaw                                          | contracts: webSearchProviders                                                                                                                                                                                                                                    |

diff --git a/docs/plugins/reference/diffs-language-pack.md b/docs/plugins/reference/diffs-language-pack.md
@@ -0,0 +1,19 @@
+---
+summary: "Adds syntax highlighting for languages outside the default diffs viewer set."
+read_when:
+  - You are installing, configuring, or auditing the diffs-language-pack plugin
+title: "Diffs Language Pack plugin"
+---
+
+# Diffs Language Pack plugin
+
+Adds syntax highlighting for languages outside the default diffs viewer set.
+
+## Distribution
+
+- Package: `@openclaw/diffs-language-pack`
+- Install route: npm; ClawHub: `clawhub:@openclaw/diffs-language-pack`
+
+## Surface
+
+plugin
diff --git a/docs/tools/diffs.md b/docs/tools/diffs.md
@@ -136,8 +136,10 @@ All fields are optional unless noted.
   Display filename for before and after mode.
 </ParamField>
 <ParamField path="lang" type="string">
-  Language override hint for before and after mode. Unknown values fall back to plain text.
+  Language override hint for before and after mode. Unknown values and languages outside the default viewer set fall back to plain text unless the
+  Diff Viewer Language Pack plugin is installed.
 </ParamField>
+
 <ParamField path="title" type="string">
   Viewer title override.
 </ParamField>
@@ -200,6 +202,22 @@ All fields are optional unless noted.
   </Accordion>
 </AccordionGroup>
 
+## Syntax highlighting
+
+OpenClaw includes syntax highlighting for common source, config, and documentation languages:
+
+`javascript`, `typescript`, `tsx`, `jsx`, `json`, `markdown`, `yaml`, `css`, `html`, `sh`, `python`, `go`, `rust`, `java`, `c`, `cpp`, `csharp`, `php`, `sql`, and `docker`.
+
+Common aliases such as `js`, `ts`, `bash`, `md`, `yml`, `c++`, and `dockerfile` are normalized to those default languages.
+
+Install the Diff Viewer Language Pack plugin to highlight other languages:
+
+```bash
+openclaw plugins install diffs-language-pack
+```
+
+With the language pack available, OpenClaw automatically uses it for languages outside the default list. Without it, those files stay readable as plain text.
+
 ## Output details contract
 
 The tool returns structured metadata under `details`.
@@ -385,6 +403,7 @@ Viewer assets:
 
 - `/plugins/diffs/assets/viewer.js`
 - `/plugins/diffs/assets/viewer-runtime.js`
+- `/plugins/diffs-language-pack/assets/viewer.js` when the diff uses a language from the Diff Viewer Language Pack
 
 The viewer document resolves those assets relative to the viewer URL, so an optional `baseUrl` path prefix is preserved for both asset requests too.
 

diff --git a/extensions/diffs-language-pack/api.ts b/extensions/diffs-language-pack/api.ts
@@ -0,0 +1,6 @@
+export {
+  definePluginEntry,
+  type OpenClawPluginApi,
+  type OpenClawPluginHttpRouteHandler,
+  type PluginLogger,
+} from "openclaw/plugin-sdk/plugin-entry";
diff --git a/extensions/diffs-language-pack/index.ts b/extensions/diffs-language-pack/index.ts
@@ -0,0 +1,9 @@
+import { definePluginEntry } from "./api.js";
+import { registerDiffsLanguagePackPlugin } from "./src/plugin.js";
+
+export default definePluginEntry({
+  id: "diffs-language-pack",
+  name: "Diff Viewer Language Pack",
+  description: "Adds syntax highlighting for languages outside the default diffs viewer set.",
+  register: registerDiffsLanguagePackPlugin,
+});
diff --git a/extensions/diffs-language-pack/openclaw.plugin.json b/extensions/diffs-language-pack/openclaw.plugin.json
@@ -0,0 +1,14 @@
+{
+  "id": "diffs-language-pack",
+  "requiresPlugins": ["diffs"],
+  "activation": {
+    "onStartup": true
+  },
+  "name": "Diff Viewer Language Pack",
+  "description": "Adds syntax highlighting for languages outside the default diffs viewer set.",
+  "configSchema": {
+    "type": "object",
+    "additionalProperties": false,
+    "properties": {}
+  }
+}
diff --git a/extensions/diffs-language-pack/package.json b/extensions/diffs-language-pack/package.json
@@ -0,0 +1,47 @@
+{
+  "name": "@openclaw/diffs-language-pack",
+  "version": "2026.5.26",
+  "description": "OpenClaw diffs viewer syntax highlighting language pack",
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/openclaw/openclaw"
+  },
+  "type": "module",
+  "scripts": {
+    "build:viewer": "node scripts/build-viewer.mjs"
+  },
+  "devDependencies": {
+    "@openclaw/plugin-sdk": "workspace:*"
+  },
+  "openclaw": {
+    "extensions": [
+      "./index.ts"
+    ],
+    "install": {
+      "npmSpec": "@openclaw/diffs-language-pack",
+      "clawhubSpec": "clawhub:@openclaw/diffs-language-pack",
+      "localPath": "extensions/diffs-language-pack",
+      "defaultChoice": "npm",
+      "minHostVersion": ">=2026.4.30"
+    },
+    "compat": {
+      "pluginApi": ">=2026.5.26"
+    },
+    "assetScripts": {
+      "build": "pnpm build:viewer"
+    },
+    "build": {
+      "openclawVersion": "2026.5.26",
+      "staticAssets": [
+        {
+          "source": "./assets/viewer-runtime.js",
+          "output": "assets/viewer-runtime.js"
+        }
+      ]
+    },
+    "release": {
+      "publishToClawHub": true,
+      "publishToNpm": true
+    }
+  }
+}
diff --git a/extensions/diffs-language-pack/scripts/build-viewer.mjs b/extensions/diffs-language-pack/scripts/build-viewer.mjs
@@ -0,0 +1,15 @@
+#!/usr/bin/env node
+
+import { spawnSync } from "node:child_process";
+import path from "node:path";
+import { fileURLToPath } from "node:url";
+
+const pluginRoot = path.resolve(path.dirname(fileURLToPath(import.meta.url)), "..");
+const repoRoot = path.resolve(pluginRoot, "../..");
+const scriptPath = path.join(repoRoot, "scripts", "build-diffs-viewer-runtime.mjs");
+
+const result = spawnSync(process.execPath, [scriptPath, "full"], {
+  cwd: repoRoot,
+  stdio: "inherit",
+});
+process.exit(result.status ?? 1);
diff --git a/extensions/diffs-language-pack/src/plugin.ts b/extensions/diffs-language-pack/src/plugin.ts
@@ -0,0 +1,64 @@
+import type { IncomingMessage, ServerResponse } from "node:http";
+import type { OpenClawPluginApi } from "../api.js";
+import { VIEWER_ASSET_PREFIX, getServedViewerAsset } from "./viewer-assets.js";
+
+export function registerDiffsLanguagePackPlugin(api: OpenClawPluginApi): void {
+  api.registerHttpRoute({
+    path: "/plugins/diffs-language-pack",
+    auth: "plugin",
+    match: "prefix",
+    handler: createDiffsLanguagePackHttpHandler(),
+  });
+}
+
+function createDiffsLanguagePackHttpHandler() {
+  return async (req: IncomingMessage, res: ServerResponse): Promise<boolean> => {
+    const parsed = parseRequestUrl(req.url);
+    if (!parsed?.pathname.startsWith(VIEWER_ASSET_PREFIX)) {
+      return false;
+    }
+    if (req.method !== "GET" && req.method !== "HEAD") {
+      respondText(res, 405, "Method not allowed");
+      return true;
+    }
+
+    const asset = await getServedViewerAsset(parsed.pathname);
+    if (!asset) {
+      respondText(res, 404, "Asset not found");
+      return true;
+    }
+
+    res.statusCode = 200;
+    setSharedHeaders(res, asset.contentType);
+    if (req.method === "HEAD") {
+      res.end();
+    } else {
+      res.end(asset.body);
+    }
+    return true;
+  };
+}
+
+function parseRequestUrl(rawUrl?: string): URL | null {
+  if (!rawUrl) {
+    return null;
+  }
+  try {
+    return new URL(rawUrl, "http://127.0.0.1");
+  } catch {
+    return null;
+  }
+}
+
+function respondText(res: ServerResponse, statusCode: number, body: string): void {
+  res.statusCode = statusCode;
+  setSharedHeaders(res, "text/plain; charset=utf-8");
+  res.end(body);
+}
+
+function setSharedHeaders(res: ServerResponse, contentType: string): void {
+  res.setHeader("cache-control", "no-store, max-age=0");
+  res.setHeader("content-type", contentType);
+  res.setHeader("x-content-type-options", "nosniff");
+  res.setHeader("referrer-policy", "no-referrer");
+}
diff --git a/extensions/diffs-language-pack/src/viewer-assets.ts b/extensions/diffs-language-pack/src/viewer-assets.ts
@@ -0,0 +1,90 @@
+import crypto from "node:crypto";
+import fs from "node:fs/promises";
+import { fileURLToPath } from "node:url";
+
+export const VIEWER_ASSET_PREFIX = "/plugins/diffs-language-pack/assets/";
+export const VIEWER_LOADER_PATH = `${VIEWER_ASSET_PREFIX}viewer.js`;
+export const VIEWER_RUNTIME_PATH = `${VIEWER_ASSET_PREFIX}viewer-runtime.js`;
+const VIEWER_RUNTIME_RELATIVE_IMPORT_PATH = "./viewer-runtime.js";
+const VIEWER_RUNTIME_CANDIDATE_RELATIVE_PATHS = [
+  "./assets/viewer-runtime.js",
+  "../assets/viewer-runtime.js",
+] as const;
+
+type ServedViewerAsset = {
+  body: string | Buffer;
+  contentType: string;
+};
+
+type RuntimeAssetCache = {
+  mtimeMs: number;
+  runtimeBody: Buffer;
+  loaderBody: string;
+};
+
+let runtimeAssetCache: RuntimeAssetCache | null = null;
+
+function isMissingFileError(error: unknown): error is NodeJS.ErrnoException {
+  return error instanceof Error && "code" in error && error.code === "ENOENT";
+}
+
+export async function resolveViewerRuntimeFileUrl(): Promise<URL> {
+  let missingFileError: NodeJS.ErrnoException | null = null;
+
+  for (const relativePath of VIEWER_RUNTIME_CANDIDATE_RELATIVE_PATHS) {
+    const candidateUrl = new URL(relativePath, import.meta.url);
+    try {
+      await fs.stat(fileURLToPath(candidateUrl));
+      return candidateUrl;
+    } catch (error) {
+      if (isMissingFileError(error)) {
+        missingFileError = error;
+        continue;
+      }
+      throw error;
+    }
+  }
+
+  if (missingFileError) {
+    throw missingFileError;
+  }
+
+  throw new Error("viewer runtime asset candidates were not checked");
+}
+
+export async function getServedViewerAsset(pathname: string): Promise<ServedViewerAsset | null> {
+  if (pathname !== VIEWER_LOADER_PATH && pathname !== VIEWER_RUNTIME_PATH) {
+    return null;
+  }
+
+  const assets = await loadViewerAssets();
+  if (pathname === VIEWER_LOADER_PATH) {
+    return {
+      body: assets.loaderBody,
+      contentType: "text/javascript; charset=utf-8",
+    };
+  }
+
+  return {
+    body: assets.runtimeBody,
+    contentType: "text/javascript; charset=utf-8",
+  };
+}
+
+async function loadViewerAssets(): Promise<RuntimeAssetCache> {
+  const runtimeUrl = await resolveViewerRuntimeFileUrl();
+  const runtimePath = fileURLToPath(runtimeUrl);
+  const runtimeStat = await fs.stat(runtimePath);
+  if (runtimeAssetCache && runtimeAssetCache.mtimeMs === runtimeStat.mtimeMs) {
+    return runtimeAssetCache;
+  }
+
+  const runtimeBody = await fs.readFile(runtimePath);
+  const hash = crypto.createHash("sha1").update(runtimeBody).digest("hex").slice(0, 12);
+  runtimeAssetCache = {
+    mtimeMs: runtimeStat.mtimeMs,
+    runtimeBody,
+    loaderBody: `import "${VIEWER_RUNTIME_RELATIVE_IMPORT_PATH}?v=${hash}";\n`,
+  };
+  return runtimeAssetCache;
+}