From e8020dfa145bf93b5f89033363f4778ebd388028 Mon Sep 17 00:00:00 2001
From: Pedro Durek <pedro.durek@shopify.com>
Date: Fri, 13 Mar 2026 18:46:15 -0600
Subject: [PATCH] feat: add set_extra_http_headers tool for
 Network.setExtraHTTPHeaders

---
 src/tools/network.ts        | 27 +++++++++++++
 tests/tools/network.test.ts | 80 +++++++++++++++++++++++++++++++++++++
 2 files changed, 107 insertions(+)

diff --git a/src/tools/network.ts b/src/tools/network.ts
index 2df445cc3..8bd59e4fb 100644
--- a/src/tools/network.ts
+++ b/src/tools/network.ts
@@ -138,3 +138,30 @@ export const getNetworkRequest = definePageTool({
     }
   },
 });
+
+export const setExtraHTTPHeaders = definePageTool({
+  name: 'set_extra_http_headers',
+  description: `Set extra HTTP headers to be sent with every request made by the selected page. Headers persist across navigations until cleared. Pass an empty object to clear all extra headers.`,
+  annotations: {
+    category: ToolCategory.NETWORK,
+    readOnlyHint: false,
+  },
+  schema: {
+    headers: zod
+      .record(zod.string(), zod.string())
+      .describe(
+        'Header name-value pairs to set, e.g. {"X-Custom": "value"}. Pass an empty object {} to clear all extra headers.',
+      ),
+  },
+  handler: async (request, response) => {
+    await request.page.pptrPage.setExtraHTTPHeaders(request.params.headers);
+    const headerCount = Object.keys(request.params.headers).length;
+    if (headerCount === 0) {
+      response.appendResponseLine('Extra HTTP headers cleared.');
+    } else {
+      response.appendResponseLine(
+        `Set ${headerCount} extra HTTP header${headerCount === 1 ? '' : 's'}: ${Object.keys(request.params.headers).join(', ')}`,
+      );
+    }
+  },
+});
diff --git a/tests/tools/network.test.ts b/tests/tools/network.test.ts
index 142555006..4268ebcda 100644
--- a/tests/tools/network.test.ts
+++ b/tests/tools/network.test.ts
@@ -10,6 +10,7 @@ import {describe, it} from 'node:test';
 import {
   getNetworkRequest,
   listNetworkRequests,
+  setExtraHTTPHeaders,
 } from '../../src/tools/network.js';
 import {serverHooks} from '../server.js';
 import {
@@ -187,4 +188,83 @@ describe('network', () => {
       });
     });
   });
+
+  describe('set_extra_http_headers', () => {
+    it('sets extra headers on requests', async () => {
+      let receivedHeaders: Record<string, string> = {};
+      server.addRoute('/headers-test', async (req, res) => {
+        receivedHeaders = req.headers as Record<string, string>;
+        res.writeHead(200, {'Content-Type': 'text/html'});
+        res.end('<main>Headers Test</main>');
+      });
+
+      await withMcpContext(async (response, context) => {
+        const page = context.getSelectedPptrPage();
+        await setExtraHTTPHeaders.handler(
+          {
+            params: {headers: {'X-Custom-Header': 'test-value'}},
+            page: context.getSelectedMcpPage(),
+          },
+          response,
+          context,
+        );
+        assert.ok(
+          response.responseLines[0]?.includes('1 extra HTTP header'),
+        );
+
+        await page.goto(server.getRoute('/headers-test'));
+        assert.strictEqual(receivedHeaders['x-custom-header'], 'test-value');
+      });
+    });
+
+    it('clears extra headers when empty object is passed', async () => {
+      await withMcpContext(async (response, context) => {
+        const page = context.getSelectedPptrPage();
+        // Set headers first.
+        await page.setExtraHTTPHeaders({'X-To-Clear': 'value'});
+
+        await setExtraHTTPHeaders.handler(
+          {
+            params: {headers: {}},
+            page: context.getSelectedMcpPage(),
+          },
+          response,
+          context,
+        );
+        assert.ok(response.responseLines[0]?.includes('cleared'));
+      });
+    });
+
+    it('headers persist across navigations', async () => {
+      const receivedHeaders: Array<Record<string, string>> = [];
+      server.addRoute('/persist-one', async (req, res) => {
+        receivedHeaders.push({...req.headers} as Record<string, string>);
+        res.writeHead(200, {'Content-Type': 'text/html'});
+        res.end('<main>Page One</main>');
+      });
+      server.addRoute('/persist-two', async (req, res) => {
+        receivedHeaders.push({...req.headers} as Record<string, string>);
+        res.writeHead(200, {'Content-Type': 'text/html'});
+        res.end('<main>Page Two</main>');
+      });
+
+      await withMcpContext(async (response, context) => {
+        const page = context.getSelectedPptrPage();
+        await setExtraHTTPHeaders.handler(
+          {
+            params: {headers: {'X-Persist': 'yes'}},
+            page: context.getSelectedMcpPage(),
+          },
+          response,
+          context,
+        );
+
+        await page.goto(server.getRoute('/persist-one'));
+        await page.goto(server.getRoute('/persist-two'));
+
+        assert.strictEqual(receivedHeaders[0]?.['x-persist'], 'yes');
+        assert.strictEqual(receivedHeaders[1]?.['x-persist'], 'yes');
+      });
+    });
+  });
 });