From 3d29ae328f906215e758a37a16a4e9cc3604af5c Mon Sep 17 00:00:00 2001
From: Danilo Campos <danilo@posthog.com>
Date: Thu, 2 Apr 2026 14:48:24 +0100
Subject: [PATCH] Cloudflare detection and context augmentation

---
 src/lib/agent-runner.ts         | 21 +++++++-
 src/lib/cloudflare-detection.ts | 90 +++++++++++++++++++++++++++++++++
 2 files changed, 110 insertions(+), 1 deletion(-)
 create mode 100644 src/lib/cloudflare-detection.ts

diff --git a/src/lib/agent-runner.ts b/src/lib/agent-runner.ts
index d8686ae7..06c50d5c 100644
--- a/src/lib/agent-runner.ts
+++ b/src/lib/agent-runner.ts
@@ -39,6 +39,10 @@ import {
   registerCleanup,
 } from '../utils/wizard-abort';
 import { formatScanReport, writeScanReport } from './yara-hooks';
+import {
+  detectCloudflareTarget,
+  fetchCloudflareReference,
+} from './cloudflare-detection';
 
 /**
  * Build a WizardOptions bag from a WizardSession (for code that still expects WizardOptions).
@@ -210,6 +214,15 @@ export async function runAgentWizard(
     analytics.setTag(key, value);
   });
 
+  // Detect Cloudflare Workers target and fetch runtime reference if needed
+  const isCloudflare = await detectCloudflareTarget(session.installDir);
+  let cloudflareReference: string | null = null;
+  if (isCloudflare) {
+    logToFile('[agent-runner] Cloudflare Workers target detected');
+    analytics.setTag('cloudflare', 'true');
+    cloudflareReference = await fetchCloudflareReference(skillsBaseUrl);
+  }
+
   const integrationPrompt = buildIntegrationPrompt(
     config,
     {
@@ -220,6 +233,7 @@ export async function runAgentWizard(
       projectId,
     },
     frameworkContext,
+    cloudflareReference,
   );
 
   // Initialize and run agent
@@ -407,6 +421,7 @@ function buildIntegrationPrompt(
     projectId: number;
   },
   frameworkContext: Record<string, unknown>,
+  cloudflareReference?: string | null,
 ): string {
   const additionalLines = config.prompts.getAdditionalContextLines
     ? config.prompts.getAdditionalContextLines(frameworkContext)
@@ -417,6 +432,10 @@ function buildIntegrationPrompt(
       ? '\n' + additionalLines.map((line) => `- ${line}`).join('\n')
       : '';
 
+  const runtimeOverrides = cloudflareReference
+    ? `\n\n---\n\n${cloudflareReference}`
+    : '';
+
   return `You have access to the PostHog MCP server which provides skills to integrate PostHog into this ${
     config.metadata.name
   } project.
@@ -459,7 +478,7 @@ STEP 5: Set up environment variables for PostHog using the wizard-tools MCP serv
    - Reference these environment variables in the code files you create instead of hardcoding the public token and host.
 
 Important: Use the detect_package_manager tool (from the wizard-tools MCP server) to determine which package manager the project uses. Do not manually search for lockfiles or config files. Always install packages as a background task. Don't await completion; proceed with other work immediately after starting the installation. You must read a file immediately before attempting to write it, even if you have previously read it; failure to do so will cause a tool failure.
-
+${runtimeOverrides}
 
 `;
 }
diff --git a/src/lib/cloudflare-detection.ts b/src/lib/cloudflare-detection.ts
new file mode 100644
index 00000000..3a84ddb6
--- /dev/null
+++ b/src/lib/cloudflare-detection.ts
@@ -0,0 +1,90 @@
+import fg from 'fast-glob';
+import fs from 'fs';
+import path from 'path';
+import { logToFile } from '../utils/debug';
+
+/**
+ * Detect whether the project targets Cloudflare Workers.
+ *
+ * Checks for:
+ * 1. wrangler.toml / wrangler.jsonc / wrangler.json in project root
+ * 2. Cloudflare adapter packages in dependencies (@react-router/cloudflare,
+ *    @astrojs/cloudflare, @sveltejs/adapter-cloudflare, etc.)
+ */
+export async function detectCloudflareTarget(
+  installDir: string,
+): Promise<boolean> {
+  // Check for wrangler config files
+  const wranglerFiles = await fg('wrangler.@(toml|jsonc|json)', {
+    cwd: installDir,
+    dot: true,
+  });
+  if (wranglerFiles.length > 0) {
+    logToFile(
+      `[cloudflare-detection] detected via wrangler config: ${wranglerFiles[0]}`,
+    );
+    return true;
+  }
+
+  // Check for Cloudflare adapter/platform packages in deps
+  try {
+    const packageJsonPath = path.join(installDir, 'package.json');
+    const content = fs.readFileSync(packageJsonPath, 'utf-8');
+    const packageJson = JSON.parse(content);
+    const allDeps = {
+      ...packageJson.dependencies,
+      ...packageJson.devDependencies,
+    };
+
+    const cloudflarePackages = Object.keys(allDeps).filter(
+      (dep) =>
+        dep === '@react-router/cloudflare' ||
+        dep === '@astrojs/cloudflare' ||
+        dep === '@sveltejs/adapter-cloudflare' ||
+        dep === '@sveltejs/adapter-cloudflare-workers' ||
+        dep === '@cloudflare/workers-types' ||
+        dep === 'wrangler',
+    );
+
+    if (cloudflarePackages.length > 0) {
+      logToFile(
+        `[cloudflare-detection] detected via packages: ${cloudflarePackages.join(
+          ', ',
+        )}`,
+      );
+      return true;
+    }
+  } catch {
+    // package.json not found or invalid
+  }
+
+  return false;
+}
+
+/**
+ * Fetch the Cloudflare Workers reference from the skills server.
+ * Returns the markdown content, or null on failure.
+ */
+export async function fetchCloudflareReference(
+  skillsBaseUrl: string,
+): Promise<string | null> {
+  try {
+    const url = `${skillsBaseUrl}/cloudflare-workers.md`;
+    logToFile(`[cloudflare-detection] fetching reference from ${url}`);
+    const resp = await fetch(url);
+    if (resp.ok) {
+      const text = await resp.text();
+      logToFile(
+        `[cloudflare-detection] loaded reference (${text.length} chars)`,
+      );
+      return text;
+    }
+    logToFile(
+      `[cloudflare-detection] reference fetch failed: HTTP ${resp.status}`,
+    );
+    return null;
+  } catch (err: any) {
+    logToFile(`[cloudflare-detection] reference fetch error: ${err.message}`);
+    return null;
+  }
+}