From cf921b73614db28527b4f2a3e23b1c6db4231fc7 Mon Sep 17 00:00:00 2001
From: Kevin van Zonneveld <kevin@vanzonneveld.net>
Date: Tue, 3 Feb 2026 20:28:00 +0100
Subject: [PATCH] Override Transloadit-Client header for MCP

---
 .changeset/mcp-client-header.md               |  6 ++++++
 packages/mcp-server/src/server.ts             |  7 +++++++
 packages/node/src/Transloadit.ts              |  6 +++++-
 .../test/unit/test-transloadit-client.test.ts | 19 +++++++++++++++++++
 4 files changed, 37 insertions(+), 1 deletion(-)
 create mode 100644 .changeset/mcp-client-header.md

diff --git a/.changeset/mcp-client-header.md b/.changeset/mcp-client-header.md
new file mode 100644
index 00000000..2d53e499
--- /dev/null
+++ b/.changeset/mcp-client-header.md
@@ -0,0 +1,6 @@
+---
+"@transloadit/node": patch
+"@transloadit/mcp-server": patch
+---
+
+Allow overriding the Transloadit-Client header and set MCP server requests to its own client name.
diff --git a/packages/mcp-server/src/server.ts b/packages/mcp-server/src/server.ts
index c50bd8ad..1375ebd6 100644
--- a/packages/mcp-server/src/server.ts
+++ b/packages/mcp-server/src/server.ts
@@ -24,6 +24,7 @@ export type TransloaditMcpServerOptions = {
   endpoint?: string
   serverName?: string
   serverVersion?: string
+  clientName?: string
 }
 
 type LintIssueOutput = {
@@ -278,11 +279,15 @@ const buildToolError = (
     ],
   })
 
+const getClientName = (options: TransloaditMcpServerOptions): string =>
+  options.clientName ?? `mcp-server:${packageJson.version}`
+
 const createLintClient = (options: TransloaditMcpServerOptions): Transloadit =>
   new Transloadit({
     authKey: options.authKey ?? 'mcp',
     authSecret: options.authSecret ?? 'mcp',
     endpoint: options.endpoint,
+    clientName: getClientName(options),
   })
 
 const getHeaderValue = (headers: HeaderMap | undefined, name: string): string | undefined => {
@@ -315,6 +320,7 @@ const createLiveClient = (
         authKey: options.authKey,
         authSecret: options.authSecret,
         endpoint: options.endpoint,
+        clientName: getClientName(options),
       }),
     }
   }
@@ -333,6 +339,7 @@ const createLiveClient = (
       authKey: options.authKey,
       authSecret: options.authSecret,
       endpoint: options.endpoint,
+      clientName: getClientName(options),
     }),
   }
 }
diff --git a/packages/node/src/Transloadit.ts b/packages/node/src/Transloadit.ts
index 60d8c385..14c5dbd0 100644
--- a/packages/node/src/Transloadit.ts
+++ b/packages/node/src/Transloadit.ts
@@ -322,6 +322,7 @@ type BaseOptions = {
   timeout?: number
   gotRetry?: Partial<RetryOptions>
   validateResponses?: boolean
+  clientName?: string
 }
 
 export type Options = BaseOptions & (AuthKeySecret | AuthToken)
@@ -341,6 +342,8 @@ export class Transloadit {
 
   private _gotRetry: Partial<RetryOptions>
 
+  private _clientName: string
+
   private _lastUsedAssemblyUrl = ''
 
   private _validateResponses = false
@@ -369,6 +372,7 @@ export class Transloadit {
     this._endpoint = opts.endpoint || 'https://api2.transloadit.com'
     this._maxRetries = opts.maxRetries != null ? opts.maxRetries : 5
     this._defaultTimeout = opts.timeout != null ? opts.timeout : 60000
+    this._clientName = opts.clientName?.trim() || `node-sdk:${version}`
 
     // Passed on to got https://github.com/sindresorhus/got/blob/main/documentation/7-retry.md
     this._gotRetry = opts.gotRetry != null ? opts.gotRetry : { limit: 0 }
@@ -1258,7 +1262,7 @@ export class Transloadit {
         body: form,
         timeout,
         headers: {
-          'Transloadit-Client': `node-sdk:${version}`,
+          'Transloadit-Client': this._clientName,
           'User-Agent': undefined, // Remove got's user-agent
           ...(this._authToken ? { Authorization: `Bearer ${this._authToken}` } : {}),
           ...headers,
diff --git a/packages/node/test/unit/test-transloadit-client.test.ts b/packages/node/test/unit/test-transloadit-client.test.ts
index 1b5f83c2..2fc7066a 100644
--- a/packages/node/test/unit/test-transloadit-client.test.ts
+++ b/packages/node/test/unit/test-transloadit-client.test.ts
@@ -388,6 +388,25 @@ describe('Transloadit', () => {
         expect.objectContaining({ headers: { 'Transloadit-Client': `node-sdk:${version}` } }),
       )
     })
+
+    it('should allow overriding the "Transloadit-Client" header', async () => {
+      const client = new Transloadit({
+        authKey: 'foo_key',
+        authSecret: 'foo_secret',
+        clientName: 'mcp-server:1.2.3',
+      })
+
+      const get = mockGot('get')
+
+      const url = '/some-url'
+      // @ts-expect-error This tests private internals
+      await client._remoteJson({ url, method: 'get', isTrustedUrl: true })
+
+      expect(get).toHaveBeenCalledWith(
+        expect.any(String),
+        expect.objectContaining({ headers: { 'Transloadit-Client': 'mcp-server:1.2.3' } }),
+      )
+    })
   })
 
   describe('getSignedSmartCDNUrl', () => {