From 869a8aa557dfae546e648a5d92e86432703c2cff Mon Sep 17 00:00:00 2001
From: "stainless-app[bot]"
 <142633134+stainless-app[bot]@users.noreply.github.com>
Date: Sat, 14 Feb 2026 05:39:42 +0000
Subject: [PATCH 01/10] chore(mcp): forward STAINLESS_API_KEY to docs search
 endpoint

---
 packages/mcp-server/src/docs-search-tool.ts | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/packages/mcp-server/src/docs-search-tool.ts b/packages/mcp-server/src/docs-search-tool.ts
index 078b09f..8bfc3cb 100644
--- a/packages/mcp-server/src/docs-search-tool.ts
+++ b/packages/mcp-server/src/docs-search-tool.ts
@@ -1,6 +1,7 @@
 // File generated from our OpenAPI spec by Stainless. See CONTRIBUTING.md for details.
 
 import { Metadata, asTextContentResult } from './types';
+import { readEnv } from './server';
 
 import { Tool } from '@modelcontextprotocol/sdk/types.js';
 
@@ -45,7 +46,12 @@ const docsSearchURL =
 export const handler = async (_: unknown, args: Record<string, unknown> | undefined) => {
   const body = args as any;
   const query = new URLSearchParams(body).toString();
-  const result = await fetch(`${docsSearchURL}?${query}`);
+  const stainlessAPIKey = readEnv('STAINLESS_API_KEY');
+  const result = await fetch(`${docsSearchURL}?${query}`, {
+    headers: {
+      ...(stainlessAPIKey && { Authorization: stainlessAPIKey }),
+    },
+  });
 
   if (!result.ok) {
     throw new Error(

From 01a45632c1ee8e9eec2a3995a1b7891059d1b101 Mon Sep 17 00:00:00 2001
From: "stainless-app[bot]"
 <142633134+stainless-app[bot]@users.noreply.github.com>
Date: Sat, 14 Feb 2026 05:42:00 +0000
Subject: [PATCH 02/10] chore(internal): improve layout of generated MCP server
 files

---
 .../mcp-server/src/{headers.ts => auth.ts}    |  0
 packages/mcp-server/src/code-tool.ts          |  2 +-
 packages/mcp-server/src/docs-search-tool.ts   |  2 +-
 packages/mcp-server/src/http.ts               |  5 ++--
 packages/mcp-server/src/methods.ts            |  2 ++
 packages/mcp-server/src/options.ts            |  2 ++
 packages/mcp-server/src/server.ts             | 28 +------------------
 packages/mcp-server/src/util.ts               | 25 +++++++++++++++++
 8 files changed, 35 insertions(+), 31 deletions(-)
 rename packages/mcp-server/src/{headers.ts => auth.ts} (100%)
 create mode 100644 packages/mcp-server/src/util.ts

diff --git a/packages/mcp-server/src/headers.ts b/packages/mcp-server/src/auth.ts
similarity index 100%
rename from packages/mcp-server/src/headers.ts
rename to packages/mcp-server/src/auth.ts
diff --git a/packages/mcp-server/src/code-tool.ts b/packages/mcp-server/src/code-tool.ts
index 25d04c6..5c32c60 100644
--- a/packages/mcp-server/src/code-tool.ts
+++ b/packages/mcp-server/src/code-tool.ts
@@ -2,7 +2,7 @@
 
 import { McpTool, Metadata, ToolCallResult, asErrorResult, asTextContentResult } from './types';
 import { Tool } from '@modelcontextprotocol/sdk/types.js';
-import { readEnv, requireValue } from './server';
+import { readEnv, requireValue } from './util';
 import { WorkerInput, WorkerOutput } from './code-tool-types';
 import { SdkMethod } from './methods';
 import { SendblueAPI } from 'sendblue';
diff --git a/packages/mcp-server/src/docs-search-tool.ts b/packages/mcp-server/src/docs-search-tool.ts
index 8bfc3cb..e110c73 100644
--- a/packages/mcp-server/src/docs-search-tool.ts
+++ b/packages/mcp-server/src/docs-search-tool.ts
@@ -1,7 +1,7 @@
 // File generated from our OpenAPI spec by Stainless. See CONTRIBUTING.md for details.
 
 import { Metadata, asTextContentResult } from './types';
-import { readEnv } from './server';
+import { readEnv } from './util';
 
 import { Tool } from '@modelcontextprotocol/sdk/types.js';
 
diff --git a/packages/mcp-server/src/http.ts b/packages/mcp-server/src/http.ts
index 8ca827c..4940a6b 100644
--- a/packages/mcp-server/src/http.ts
+++ b/packages/mcp-server/src/http.ts
@@ -2,12 +2,13 @@
 
 import { McpServer } from '@modelcontextprotocol/sdk/server/mcp';
 import { StreamableHTTPServerTransport } from '@modelcontextprotocol/sdk/server/streamableHttp.js';
+import { ClientOptions } from 'sendblue';
 import express from 'express';
 import morgan from 'morgan';
 import morganBody from 'morgan-body';
+import { parseAuthHeaders } from './auth';
 import { McpOptions } from './options';
-import { ClientOptions, initMcpServer, newMcpServer } from './server';
-import { parseAuthHeaders } from './headers';
+import { initMcpServer, newMcpServer } from './server';
 
 const newServer = async ({
   clientOptions,
diff --git a/packages/mcp-server/src/methods.ts b/packages/mcp-server/src/methods.ts
index 52f99cf..9424c8d 100644
--- a/packages/mcp-server/src/methods.ts
+++ b/packages/mcp-server/src/methods.ts
@@ -1,3 +1,5 @@
+// File generated from our OpenAPI spec by Stainless. See CONTRIBUTING.md for details.
+
 import { McpOptions } from './options';
 
 export type SdkMethod = {
diff --git a/packages/mcp-server/src/options.ts b/packages/mcp-server/src/options.ts
index 92d1b07..cfde21d 100644
--- a/packages/mcp-server/src/options.ts
+++ b/packages/mcp-server/src/options.ts
@@ -1,3 +1,5 @@
+// File generated from our OpenAPI spec by Stainless. See CONTRIBUTING.md for details.
+
 import qs from 'qs';
 import yargs from 'yargs';
 import { hideBin } from 'yargs/helpers';
diff --git a/packages/mcp-server/src/server.ts b/packages/mcp-server/src/server.ts
index f128f02..c739e45 100644
--- a/packages/mcp-server/src/server.ts
+++ b/packages/mcp-server/src/server.ts
@@ -14,9 +14,7 @@ import docsSearchTool from './docs-search-tool';
 import { McpOptions } from './options';
 import { blockedMethodsForCodeTool } from './methods';
 import { HandlerFunction, McpTool } from './types';
-
-export { McpOptions } from './options';
-export { ClientOptions } from 'sendblue';
+import { readEnv } from './util';
 
 async function getInstructions() {
   // This API key is optional; providing it allows the server to fetch instructions for unreleased versions.
@@ -169,27 +167,3 @@ export async function executeHandler(
 ) {
   return await handler(client, args || {});
 }
-
-export const readEnv = (env: string): string | undefined => {
-  if (typeof (globalThis as any).process !== 'undefined') {
-    return (globalThis as any).process.env?.[env]?.trim();
-  } else if (typeof (globalThis as any).Deno !== 'undefined') {
-    return (globalThis as any).Deno.env?.get?.(env)?.trim();
-  }
-  return;
-};
-
-export const readEnvOrError = (env: string): string => {
-  let envValue = readEnv(env);
-  if (envValue === undefined) {
-    throw new Error(`Environment variable ${env} is not set`);
-  }
-  return envValue;
-};
-
-export const requireValue = <T>(value: T | undefined, description: string): T => {
-  if (value === undefined) {
-    throw new Error(`Missing required value: ${description}`);
-  }
-  return value;
-};
diff --git a/packages/mcp-server/src/util.ts b/packages/mcp-server/src/util.ts
new file mode 100644
index 0000000..40ed550
--- /dev/null
+++ b/packages/mcp-server/src/util.ts
@@ -0,0 +1,25 @@
+// File generated from our OpenAPI spec by Stainless. See CONTRIBUTING.md for details.
+
+export const readEnv = (env: string): string | undefined => {
+  if (typeof (globalThis as any).process !== 'undefined') {
+    return (globalThis as any).process.env?.[env]?.trim();
+  } else if (typeof (globalThis as any).Deno !== 'undefined') {
+    return (globalThis as any).Deno.env?.get?.(env)?.trim();
+  }
+  return;
+};
+
+export const readEnvOrError = (env: string): string => {
+  let envValue = readEnv(env);
+  if (envValue === undefined) {
+    throw new Error(`Environment variable ${env} is not set`);
+  }
+  return envValue;
+};
+
+export const requireValue = <T>(value: T | undefined, description: string): T => {
+  if (value === undefined) {
+    throw new Error(`Missing required value: ${description}`);
+  }
+  return value;
+};

From 06364085dd59f4b43b2f0f95b8bab83435fa9ffb Mon Sep 17 00:00:00 2001
From: "stainless-app[bot]"
 <142633134+stainless-app[bot]@users.noreply.github.com>
Date: Wed, 18 Feb 2026 05:18:02 +0000
Subject: [PATCH 03/10] chore(internal/client): fix form-urlencoded requests

---
 src/client.ts | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/src/client.ts b/src/client.ts
index 0260ed4..377a997 100644
--- a/src/client.ts
+++ b/src/client.ts
@@ -764,6 +764,14 @@ export class SendblueAPI {
         (Symbol.iterator in body && 'next' in body && typeof body.next === 'function'))
     ) {
       return { bodyHeaders: undefined, body: Shims.ReadableStreamFrom(body as AsyncIterable<Uint8Array>) };
+    } else if (
+      typeof body === 'object' &&
+      headers.values.get('content-type') === 'application/x-www-form-urlencoded'
+    ) {
+      return {
+        bodyHeaders: { 'content-type': 'application/x-www-form-urlencoded' },
+        body: this.stringifyQuery(body as Record<string, unknown>),
+      };
     } else {
       return this.#encoder({ body, headers });
     }

From cdbf955893b151aa89778d292b3e041a476e0306 Mon Sep 17 00:00:00 2001
From: "stainless-app[bot]"
 <142633134+stainless-app[bot]@users.noreply.github.com>
Date: Wed, 18 Feb 2026 05:22:04 +0000
Subject: [PATCH 04/10] chore(internal): allow setting x-stainless-api-key
 header on mcp server requests

---
 packages/mcp-server/src/auth.ts             | 17 ++++++++-
 packages/mcp-server/src/code-tool.ts        | 33 ++++++++++-------
 packages/mcp-server/src/docs-search-tool.ts | 15 ++++----
 packages/mcp-server/src/http.ts             | 21 +++++++----
 packages/mcp-server/src/options.ts          |  9 +++++
 packages/mcp-server/src/server.ts           | 40 +++++++++++++--------
 packages/mcp-server/src/stdio.ts            |  4 +--
 packages/mcp-server/src/types.ts            | 16 ++++++---
 8 files changed, 109 insertions(+), 46 deletions(-)

diff --git a/packages/mcp-server/src/auth.ts b/packages/mcp-server/src/auth.ts
index dde3306..a4eff23 100644
--- a/packages/mcp-server/src/auth.ts
+++ b/packages/mcp-server/src/auth.ts
@@ -2,8 +2,9 @@
 
 import { IncomingMessage } from 'node:http';
 import { ClientOptions } from 'sendblue';
+import { McpOptions } from './options';
 
-export const parseAuthHeaders = (req: IncomingMessage, required?: boolean): Partial<ClientOptions> => {
+export const parseClientAuthHeaders = (req: IncomingMessage, required?: boolean): Partial<ClientOptions> => {
   const apiKey =
     Array.isArray(req.headers['sb-api-key-id']) ?
       req.headers['sb-api-key-id'][0]
@@ -14,3 +15,17 @@ export const parseAuthHeaders = (req: IncomingMessage, required?: boolean): Part
     : req.headers['sb-api-secret-key'];
   return { apiKey, apiSecret };
 };
+
+export const getStainlessApiKey = (req: IncomingMessage, mcpOptions: McpOptions): string | undefined => {
+  // Try to get the key from the x-stainless-api-key header
+  const headerKey =
+    Array.isArray(req.headers['x-stainless-api-key']) ?
+      req.headers['x-stainless-api-key'][0]
+    : req.headers['x-stainless-api-key'];
+  if (headerKey && typeof headerKey === 'string') {
+    return headerKey;
+  }
+
+  // Fall back to value set in the mcpOptions (e.g. from environment variable), if provided
+  return mcpOptions.stainlessApiKey;
+};
diff --git a/packages/mcp-server/src/code-tool.ts b/packages/mcp-server/src/code-tool.ts
index 5c32c60..fd36d75 100644
--- a/packages/mcp-server/src/code-tool.ts
+++ b/packages/mcp-server/src/code-tool.ts
@@ -1,11 +1,17 @@
 // File generated from our OpenAPI spec by Stainless. See CONTRIBUTING.md for details.
 
-import { McpTool, Metadata, ToolCallResult, asErrorResult, asTextContentResult } from './types';
+import {
+  McpRequestContext,
+  McpTool,
+  Metadata,
+  ToolCallResult,
+  asErrorResult,
+  asTextContentResult,
+} from './types';
 import { Tool } from '@modelcontextprotocol/sdk/types.js';
 import { readEnv, requireValue } from './util';
 import { WorkerInput, WorkerOutput } from './code-tool-types';
 import { SdkMethod } from './methods';
-import { SendblueAPI } from 'sendblue';
 
 const prompt = `Runs JavaScript code to interact with the Sendblue API API.
 
@@ -40,7 +46,7 @@ Variables will not persist between calls, so make sure to return or log any data
  *
  * @param endpoints - The endpoints to include in the list.
  */
-export function codeTool(params: { blockedMethods: SdkMethod[] | undefined }): McpTool {
+export function codeTool({ blockedMethods }: { blockedMethods: SdkMethod[] | undefined }): McpTool {
   const metadata: Metadata = { resource: 'all', operation: 'write', tags: [] };
   const tool: Tool = {
     name: 'execute',
@@ -60,19 +66,24 @@ export function codeTool(params: { blockedMethods: SdkMethod[] | undefined }): M
       required: ['code'],
     },
   };
-  const handler = async (client: SendblueAPI, args: any): Promise<ToolCallResult> => {
+  const handler = async ({
+    reqContext,
+    args,
+  }: {
+    reqContext: McpRequestContext;
+    args: any;
+  }): Promise<ToolCallResult> => {
     const code = args.code as string;
     const intent = args.intent as string | undefined;
+    const client = reqContext.client;
 
     // Do very basic blocking of code that includes forbidden method names.
     //
     // WARNING: This is not secure against obfuscation and other evasion methods. If
     // stronger security blocks are required, then these should be enforced in the downstream
     // API (e.g., by having users call the MCP server with API keys with limited permissions).
-    if (params.blockedMethods) {
-      const blockedMatches = params.blockedMethods.filter((method) =>
-        code.includes(method.fullyQualifiedName),
-      );
+    if (blockedMethods) {
+      const blockedMatches = blockedMethods.filter((method) => code.includes(method.fullyQualifiedName));
       if (blockedMatches.length > 0) {
         return asErrorResult(
           `The following methods have been blocked by the MCP server and cannot be used in code execution: ${blockedMatches
@@ -82,16 +93,14 @@ export function codeTool(params: { blockedMethods: SdkMethod[] | undefined }): M
       }
     }
 
-    // this is not required, but passing a Stainless API key for the matching project_name
-    // will allow you to run code-mode queries against non-published versions of your SDK.
-    const stainlessAPIKey = readEnv('STAINLESS_API_KEY');
     const codeModeEndpoint =
       readEnv('CODE_MODE_ENDPOINT_URL') ?? 'https://api.stainless.com/api/ai/code-tool';
 
+    // Setting a Stainless API key authenticates requests to the code tool endpoint.
     const res = await fetch(codeModeEndpoint, {
       method: 'POST',
       headers: {
-        ...(stainlessAPIKey && { Authorization: stainlessAPIKey }),
+        ...(reqContext.stainlessApiKey && { Authorization: reqContext.stainlessApiKey }),
         'Content-Type': 'application/json',
         client_envs: JSON.stringify({
           SENDBLUE_API_API_KEY: requireValue(
diff --git a/packages/mcp-server/src/docs-search-tool.ts b/packages/mcp-server/src/docs-search-tool.ts
index e110c73..ec49dcf 100644
--- a/packages/mcp-server/src/docs-search-tool.ts
+++ b/packages/mcp-server/src/docs-search-tool.ts
@@ -1,8 +1,6 @@
 // File generated from our OpenAPI spec by Stainless. See CONTRIBUTING.md for details.
 
-import { Metadata, asTextContentResult } from './types';
-import { readEnv } from './util';
-
+import { Metadata, McpRequestContext, asTextContentResult } from './types';
 import { Tool } from '@modelcontextprotocol/sdk/types.js';
 
 export const metadata: Metadata = {
@@ -43,13 +41,18 @@ export const tool: Tool = {
 const docsSearchURL =
   process.env['DOCS_SEARCH_URL'] || 'https://api.stainless.com/api/projects/sendblue-api/docs/search';
 
-export const handler = async (_: unknown, args: Record<string, unknown> | undefined) => {
+export const handler = async ({
+  reqContext,
+  args,
+}: {
+  reqContext: McpRequestContext;
+  args: Record<string, unknown> | undefined;
+}) => {
   const body = args as any;
   const query = new URLSearchParams(body).toString();
-  const stainlessAPIKey = readEnv('STAINLESS_API_KEY');
   const result = await fetch(`${docsSearchURL}?${query}`, {
     headers: {
-      ...(stainlessAPIKey && { Authorization: stainlessAPIKey }),
+      ...(reqContext.stainlessApiKey && { Authorization: reqContext.stainlessApiKey }),
     },
   });
 
diff --git a/packages/mcp-server/src/http.ts b/packages/mcp-server/src/http.ts
index 4940a6b..2a0c705 100644
--- a/packages/mcp-server/src/http.ts
+++ b/packages/mcp-server/src/http.ts
@@ -6,7 +6,7 @@ import { ClientOptions } from 'sendblue';
 import express from 'express';
 import morgan from 'morgan';
 import morganBody from 'morgan-body';
-import { parseAuthHeaders } from './auth';
+import { getStainlessApiKey, parseClientAuthHeaders } from './auth';
 import { McpOptions } from './options';
 import { initMcpServer, newMcpServer } from './server';
 
@@ -21,10 +21,12 @@ const newServer = async ({
   req: express.Request;
   res: express.Response;
 }): Promise<McpServer | null> => {
-  const server = await newMcpServer();
+  const stainlessApiKey = getStainlessApiKey(req, mcpOptions);
+  const server = await newMcpServer(stainlessApiKey);
 
   try {
-    const authOptions = parseAuthHeaders(req, false);
+    const authOptions = parseClientAuthHeaders(req, false);
+
     await initMcpServer({
       server: server,
       mcpOptions: mcpOptions,
@@ -32,6 +34,7 @@ const newServer = async ({
         ...clientOptions,
         ...authOptions,
       },
+      stainlessApiKey: stainlessApiKey,
     });
   } catch (error) {
     res.status(401).json({
@@ -112,13 +115,17 @@ export const streamableHTTPApp = ({
   return app;
 };
 
-export const launchStreamableHTTPServer = async (params: {
+export const launchStreamableHTTPServer = async ({
+  mcpOptions,
+  debug,
+  port,
+}: {
   mcpOptions: McpOptions;
   debug: boolean;
   port: number | string | undefined;
 }) => {
-  const app = streamableHTTPApp({ mcpOptions: params.mcpOptions, debug: params.debug });
-  const server = app.listen(params.port);
+  const app = streamableHTTPApp({ mcpOptions, debug });
+  const server = app.listen(port);
   const address = server.address();
 
   if (typeof address === 'string') {
@@ -126,6 +133,6 @@ export const launchStreamableHTTPServer = async (params: {
   } else if (address !== null) {
     console.error(`MCP Server running on streamable HTTP on port ${address.port}`);
   } else {
-    console.error(`MCP Server running on streamable HTTP on port ${params.port}`);
+    console.error(`MCP Server running on streamable HTTP on port ${port}`);
   }
 };
diff --git a/packages/mcp-server/src/options.ts b/packages/mcp-server/src/options.ts
index cfde21d..32a8871 100644
--- a/packages/mcp-server/src/options.ts
+++ b/packages/mcp-server/src/options.ts
@@ -4,6 +4,7 @@ import qs from 'qs';
 import yargs from 'yargs';
 import { hideBin } from 'yargs/helpers';
 import z from 'zod';
+import { readEnv } from './util';
 
 export type CLIOptions = McpOptions & {
   debug: boolean;
@@ -14,6 +15,7 @@ export type CLIOptions = McpOptions & {
 
 export type McpOptions = {
   includeDocsTools?: boolean | undefined;
+  stainlessApiKey?: string | undefined;
   codeAllowHttpGets?: boolean | undefined;
   codeAllowedMethods?: string[] | undefined;
   codeBlockedMethods?: string[] | undefined;
@@ -51,6 +53,12 @@ export function parseCLIOptions(): CLIOptions {
       description: 'Port to serve on if using http transport',
     })
     .option('socket', { type: 'string', description: 'Unix socket to serve on if using http transport' })
+    .option('stainless-api-key', {
+      type: 'string',
+      default: readEnv('STAINLESS_API_KEY'),
+      description:
+        'API key for Stainless. Used to authenticate requests to Stainless-hosted tools endpoints.',
+    })
     .option('tools', {
       type: 'string',
       array: true,
@@ -81,6 +89,7 @@ export function parseCLIOptions(): CLIOptions {
   return {
     ...(includeDocsTools !== undefined && { includeDocsTools }),
     debug: !!argv.debug,
+    stainlessApiKey: argv.stainlessApiKey,
     codeAllowHttpGets: argv.codeAllowHttpGets,
     codeAllowedMethods: argv.codeAllowedMethods,
     codeBlockedMethods: argv.codeBlockedMethods,
diff --git a/packages/mcp-server/src/server.ts b/packages/mcp-server/src/server.ts
index c739e45..53c36b1 100644
--- a/packages/mcp-server/src/server.ts
+++ b/packages/mcp-server/src/server.ts
@@ -13,17 +13,17 @@ import { codeTool } from './code-tool';
 import docsSearchTool from './docs-search-tool';
 import { McpOptions } from './options';
 import { blockedMethodsForCodeTool } from './methods';
-import { HandlerFunction, McpTool } from './types';
+import { HandlerFunction, McpRequestContext, ToolCallResult, McpTool } from './types';
 import { readEnv } from './util';
 
-async function getInstructions() {
-  // This API key is optional; providing it allows the server to fetch instructions for unreleased versions.
-  const stainlessAPIKey = readEnv('STAINLESS_API_KEY');
+async function getInstructions(stainlessApiKey: string | undefined): Promise<string> {
+  // Setting the stainless API key is optional, but may be required
+  // to authenticate requests to the Stainless API.
   const response = await fetch(
     readEnv('CODE_MODE_INSTRUCTIONS_URL') ?? 'https://api.stainless.com/api/ai/instructions/sendblue-api',
     {
       method: 'GET',
-      headers: { ...(stainlessAPIKey && { Authorization: stainlessAPIKey }) },
+      headers: { ...(stainlessApiKey && { Authorization: stainlessApiKey }) },
     },
   );
 
@@ -52,14 +52,14 @@ async function getInstructions() {
   return instructions;
 }
 
-export const newMcpServer = async () =>
+export const newMcpServer = async (stainlessApiKey: string | undefined) =>
   new McpServer(
     {
       name: 'sendblue_api',
       version: '3.1.1',
     },
     {
-      instructions: await getInstructions(),
+      instructions: await getInstructions(stainlessApiKey),
       capabilities: { tools: {}, logging: {} },
     },
   );
@@ -72,6 +72,7 @@ export async function initMcpServer(params: {
   server: Server | McpServer;
   clientOptions?: ClientOptions;
   mcpOptions?: McpOptions;
+  stainlessApiKey?: string | undefined;
 }) {
   const server = params.server instanceof McpServer ? params.server.server : params.server;
 
@@ -115,7 +116,14 @@ export async function initMcpServer(params: {
       throw new Error(`Unknown tool: ${name}`);
     }
 
-    return executeHandler(mcpTool.handler, client, args);
+    return executeHandler({
+      handler: mcpTool.handler,
+      reqContext: {
+        client,
+        stainlessApiKey: params.stainlessApiKey ?? params.mcpOptions?.stainlessApiKey,
+      },
+      args,
+    });
   });
 
   server.setRequestHandler(SetLevelRequestSchema, async (request) => {
@@ -160,10 +168,14 @@ export function selectTools(options?: McpOptions): McpTool[] {
 /**
  * Runs the provided handler with the given client and arguments.
  */
-export async function executeHandler(
-  handler: HandlerFunction,
-  client: SendblueAPI,
-  args: Record<string, unknown> | undefined,
-) {
-  return await handler(client, args || {});
+export async function executeHandler({
+  handler,
+  reqContext,
+  args,
+}: {
+  handler: HandlerFunction;
+  reqContext: McpRequestContext;
+  args: Record<string, unknown> | undefined;
+}): Promise<ToolCallResult> {
+  return await handler({ reqContext, args: args || {} });
 }
diff --git a/packages/mcp-server/src/stdio.ts b/packages/mcp-server/src/stdio.ts
index 57b9912..ceccaed 100644
--- a/packages/mcp-server/src/stdio.ts
+++ b/packages/mcp-server/src/stdio.ts
@@ -3,9 +3,9 @@ import { McpOptions } from './options';
 import { initMcpServer, newMcpServer } from './server';
 
 export const launchStdioServer = async (mcpOptions: McpOptions) => {
-  const server = await newMcpServer();
+  const server = await newMcpServer(mcpOptions.stainlessApiKey);
 
-  await initMcpServer({ server, mcpOptions });
+  await initMcpServer({ server, mcpOptions, stainlessApiKey: mcpOptions.stainlessApiKey });
 
   const transport = new StdioServerTransport();
   await server.connect(transport);
diff --git a/packages/mcp-server/src/types.ts b/packages/mcp-server/src/types.ts
index 33593bf..b2a3b9f 100644
--- a/packages/mcp-server/src/types.ts
+++ b/packages/mcp-server/src/types.ts
@@ -42,10 +42,18 @@ export type ToolCallResult = {
   isError?: boolean;
 };
 
-export type HandlerFunction = (
-  client: SendblueAPI,
-  args: Record<string, unknown> | undefined,
-) => Promise<ToolCallResult>;
+export type McpRequestContext = {
+  client: SendblueAPI;
+  stainlessApiKey?: string | undefined;
+};
+
+export type HandlerFunction = ({
+  reqContext,
+  args,
+}: {
+  reqContext: McpRequestContext;
+  args: Record<string, unknown> | undefined;
+}) => Promise<ToolCallResult>;
 
 export function asTextContentResult(result: unknown): ToolCallResult {
   return {

From 3c5591018ee53d8e51d94100f6cafa0c02572046 Mon Sep 17 00:00:00 2001
From: "stainless-app[bot]"
 <142633134+stainless-app[bot]@users.noreply.github.com>
Date: Thu, 19 Feb 2026 05:18:19 +0000
Subject: [PATCH 05/10] chore(internal): cache fetch instruction calls in MCP
 server

---
 packages/mcp-server/src/instructions.ts | 74 +++++++++++++++++++++++++
 packages/mcp-server/src/server.ts       | 38 +------------
 2 files changed, 75 insertions(+), 37 deletions(-)
 create mode 100644 packages/mcp-server/src/instructions.ts

diff --git a/packages/mcp-server/src/instructions.ts b/packages/mcp-server/src/instructions.ts
new file mode 100644
index 0000000..bad350d
--- /dev/null
+++ b/packages/mcp-server/src/instructions.ts
@@ -0,0 +1,74 @@
+// File generated from our OpenAPI spec by Stainless. See CONTRIBUTING.md for details.
+
+import { readEnv } from './util';
+
+const INSTRUCTIONS_CACHE_TTL_MS = 15 * 60 * 1000; // 15 minutes
+
+interface InstructionsCacheEntry {
+  fetchedInstructions: string;
+  fetchedAt: number;
+}
+
+const instructionsCache = new Map<string, InstructionsCacheEntry>();
+
+// Periodically evict stale entries so the cache doesn't grow unboundedly.
+const _cacheCleanupInterval = setInterval(() => {
+  const now = Date.now();
+  for (const [key, entry] of instructionsCache) {
+    if (now - entry.fetchedAt > INSTRUCTIONS_CACHE_TTL_MS) {
+      instructionsCache.delete(key);
+    }
+  }
+}, INSTRUCTIONS_CACHE_TTL_MS);
+
+// Don't keep the process alive just for cleanup.
+_cacheCleanupInterval.unref();
+
+export async function getInstructions(stainlessApiKey: string | undefined): Promise<string> {
+  const cacheKey = stainlessApiKey ?? '';
+  const cached = instructionsCache.get(cacheKey);
+
+  if (cached && Date.now() - cached.fetchedAt <= INSTRUCTIONS_CACHE_TTL_MS) {
+    return cached.fetchedInstructions;
+  }
+
+  const fetchedInstructions = await fetchLatestInstructions(stainlessApiKey);
+  instructionsCache.set(cacheKey, { fetchedInstructions, fetchedAt: Date.now() });
+  return fetchedInstructions;
+}
+
+async function fetchLatestInstructions(stainlessApiKey: string | undefined): Promise<string> {
+  // Setting the stainless API key is optional, but may be required
+  // to authenticate requests to the Stainless API.
+  const response = await fetch(
+    readEnv('CODE_MODE_INSTRUCTIONS_URL') ?? 'https://api.stainless.com/api/ai/instructions/sendblue-api',
+    {
+      method: 'GET',
+      headers: { ...(stainlessApiKey && { Authorization: stainlessApiKey }) },
+    },
+  );
+
+  let instructions: string | undefined;
+  if (!response.ok) {
+    console.warn(
+      'Warning: failed to retrieve MCP server instructions. Proceeding with default instructions...',
+    );
+
+    instructions = `
+      This is the sendblue-api MCP server. You will use Code Mode to help the user perform
+      actions. You can use search_docs tool to learn about how to take action with this server. Then,
+      you will write TypeScript code using the execute tool take action. It is CRITICAL that you be
+      thoughtful and deliberate when executing code. Always try to entirely solve the problem in code
+      block: it can be as long as you need to get the job done!
+    `;
+  }
+
+  instructions ??= ((await response.json()) as { instructions: string }).instructions;
+  instructions = `
+    If needed, you can get the current time by executing Date.now().
+
+    ${instructions}
+  `;
+
+  return instructions;
+}
diff --git a/packages/mcp-server/src/server.ts b/packages/mcp-server/src/server.ts
index 53c36b1..58379dd 100644
--- a/packages/mcp-server/src/server.ts
+++ b/packages/mcp-server/src/server.ts
@@ -11,46 +11,10 @@ import { ClientOptions } from 'sendblue';
 import SendblueAPI from 'sendblue';
 import { codeTool } from './code-tool';
 import docsSearchTool from './docs-search-tool';
+import { getInstructions } from './instructions';
 import { McpOptions } from './options';
 import { blockedMethodsForCodeTool } from './methods';
 import { HandlerFunction, McpRequestContext, ToolCallResult, McpTool } from './types';
-import { readEnv } from './util';
-
-async function getInstructions(stainlessApiKey: string | undefined): Promise<string> {
-  // Setting the stainless API key is optional, but may be required
-  // to authenticate requests to the Stainless API.
-  const response = await fetch(
-    readEnv('CODE_MODE_INSTRUCTIONS_URL') ?? 'https://api.stainless.com/api/ai/instructions/sendblue-api',
-    {
-      method: 'GET',
-      headers: { ...(stainlessApiKey && { Authorization: stainlessApiKey }) },
-    },
-  );
-
-  let instructions: string | undefined;
-  if (!response.ok) {
-    console.warn(
-      'Warning: failed to retrieve MCP server instructions. Proceeding with default instructions...',
-    );
-
-    instructions = `
-      This is the sendblue-api MCP server. You will use Code Mode to help the user perform
-      actions. You can use search_docs tool to learn about how to take action with this server. Then,
-      you will write TypeScript code using the execute tool take action. It is CRITICAL that you be
-      thoughtful and deliberate when executing code. Always try to entirely solve the problem in code
-      block: it can be as long as you need to get the job done!
-    `;
-  }
-
-  instructions ??= ((await response.json()) as { instructions: string }).instructions;
-  instructions = `
-    The current time in Unix timestamps is ${Date.now()}.
-
-    ${instructions}
-  `;
-
-  return instructions;
-}
 
 export const newMcpServer = async (stainlessApiKey: string | undefined) =>
   new McpServer(

From 0b99f6924a49cdc17d09e5cdac932130f5b22a13 Mon Sep 17 00:00:00 2001
From: "stainless-app[bot]"
 <142633134+stainless-app[bot]@users.noreply.github.com>
Date: Fri, 20 Feb 2026 06:25:48 +0000
Subject: [PATCH 06/10] fix(mcp): initialize SDK lazily to avoid failing the
 connection on init errors

---
 packages/mcp-server/src/http.ts   | 31 +++++----------
 packages/mcp-server/src/index.ts  |  2 +-
 packages/mcp-server/src/server.ts | 64 ++++++++++++++++++++++++-------
 3 files changed, 62 insertions(+), 35 deletions(-)

diff --git a/packages/mcp-server/src/http.ts b/packages/mcp-server/src/http.ts
index 2a0c705..e2709b2 100644
--- a/packages/mcp-server/src/http.ts
+++ b/packages/mcp-server/src/http.ts
@@ -24,28 +24,17 @@ const newServer = async ({
   const stainlessApiKey = getStainlessApiKey(req, mcpOptions);
   const server = await newMcpServer(stainlessApiKey);
 
-  try {
-    const authOptions = parseClientAuthHeaders(req, false);
+  const authOptions = parseClientAuthHeaders(req, false);
 
-    await initMcpServer({
-      server: server,
-      mcpOptions: mcpOptions,
-      clientOptions: {
-        ...clientOptions,
-        ...authOptions,
-      },
-      stainlessApiKey: stainlessApiKey,
-    });
-  } catch (error) {
-    res.status(401).json({
-      jsonrpc: '2.0',
-      error: {
-        code: -32000,
-        message: `Unauthorized: ${error instanceof Error ? error.message : error}`,
-      },
-    });
-    return null;
-  }
+  await initMcpServer({
+    server: server,
+    mcpOptions: mcpOptions,
+    clientOptions: {
+      ...clientOptions,
+      ...authOptions,
+    },
+    stainlessApiKey: stainlessApiKey,
+  });
 
   return server;
 };
diff --git a/packages/mcp-server/src/index.ts b/packages/mcp-server/src/index.ts
index 003a765..654d25c 100644
--- a/packages/mcp-server/src/index.ts
+++ b/packages/mcp-server/src/index.ts
@@ -24,7 +24,7 @@ async function main() {
       await launchStreamableHTTPServer({
         mcpOptions: options,
         debug: options.debug,
-        port: options.port ?? options.socket,
+        port: options.socket ?? options.port,
       });
       break;
   }
diff --git a/packages/mcp-server/src/server.ts b/packages/mcp-server/src/server.ts
index 58379dd..14a1a13 100644
--- a/packages/mcp-server/src/server.ts
+++ b/packages/mcp-server/src/server.ts
@@ -55,14 +55,32 @@ export async function initMcpServer(params: {
     error: logAtLevel('error'),
   };
 
-  let client = new SendblueAPI({
-    logger,
-    ...params.clientOptions,
-    defaultHeaders: {
-      ...params.clientOptions?.defaultHeaders,
-      'X-Stainless-MCP': 'true',
-    },
-  });
+  let _client: SendblueAPI | undefined;
+  let _clientError: Error | undefined;
+  let _logLevel: 'debug' | 'info' | 'warn' | 'error' | 'off' | undefined;
+
+  const getClient = (): SendblueAPI => {
+    if (_clientError) throw _clientError;
+    if (!_client) {
+      try {
+        _client = new SendblueAPI({
+          logger,
+          ...params.clientOptions,
+          defaultHeaders: {
+            ...params.clientOptions?.defaultHeaders,
+            'X-Stainless-MCP': 'true',
+          },
+        });
+        if (_logLevel) {
+          _client = _client.withOptions({ logLevel: _logLevel });
+        }
+      } catch (e) {
+        _clientError = e instanceof Error ? e : new Error(String(e));
+        throw _clientError;
+      }
+    }
+    return _client;
+  };
 
   const providedTools = selectTools(params.mcpOptions);
   const toolMap = Object.fromEntries(providedTools.map((mcpTool) => [mcpTool.tool.name, mcpTool]));
@@ -80,6 +98,21 @@ export async function initMcpServer(params: {
       throw new Error(`Unknown tool: ${name}`);
     }
 
+    let client: SendblueAPI;
+    try {
+      client = getClient();
+    } catch (error) {
+      return {
+        content: [
+          {
+            type: 'text' as const,
+            text: `Failed to initialize client: ${error instanceof Error ? error.message : String(error)}`,
+          },
+        ],
+        isError: true,
+      };
+    }
+
     return executeHandler({
       handler: mcpTool.handler,
       reqContext: {
@@ -92,24 +125,29 @@ export async function initMcpServer(params: {
 
   server.setRequestHandler(SetLevelRequestSchema, async (request) => {
     const { level } = request.params;
+    let logLevel: 'debug' | 'info' | 'warn' | 'error' | 'off';
     switch (level) {
       case 'debug':
-        client = client.withOptions({ logLevel: 'debug' });
+        logLevel = 'debug';
         break;
       case 'info':
-        client = client.withOptions({ logLevel: 'info' });
+        logLevel = 'info';
         break;
       case 'notice':
       case 'warning':
-        client = client.withOptions({ logLevel: 'warn' });
+        logLevel = 'warn';
         break;
       case 'error':
-        client = client.withOptions({ logLevel: 'error' });
+        logLevel = 'error';
         break;
       default:
-        client = client.withOptions({ logLevel: 'off' });
+        logLevel = 'off';
         break;
     }
+    _logLevel = logLevel;
+    if (_client) {
+      _client = _client.withOptions({ logLevel });
+    }
     return {};
   });
 }

From f322a40ea28a1b9251b0e296ef7ab92a6c8d7888 Mon Sep 17 00:00:00 2001
From: "stainless-app[bot]"
 <142633134+stainless-app[bot]@users.noreply.github.com>
Date: Fri, 20 Feb 2026 06:28:43 +0000
Subject: [PATCH 07/10] chore(internal): remove mock server code

---
 scripts/mock | 41 -----------------------------------------
 scripts/test | 46 ----------------------------------------------
 2 files changed, 87 deletions(-)
 delete mode 100755 scripts/mock

diff --git a/scripts/mock b/scripts/mock
deleted file mode 100755
index 0b28f6e..0000000
--- a/scripts/mock
+++ /dev/null
@@ -1,41 +0,0 @@
-#!/usr/bin/env bash
-
-set -e
-
-cd "$(dirname "$0")/.."
-
-if [[ -n "$1" && "$1" != '--'* ]]; then
-  URL="$1"
-  shift
-else
-  URL="$(grep 'openapi_spec_url' .stats.yml | cut -d' ' -f2)"
-fi
-
-# Check if the URL is empty
-if [ -z "$URL" ]; then
-  echo "Error: No OpenAPI spec path/url provided or found in .stats.yml"
-  exit 1
-fi
-
-echo "==> Starting mock server with URL ${URL}"
-
-# Run prism mock on the given spec
-if [ "$1" == "--daemon" ]; then
-  npm exec --package=@stainless-api/prism-cli@5.15.0 -- prism mock "$URL" &> .prism.log &
-
-  # Wait for server to come online
-  echo -n "Waiting for server"
-  while ! grep -q "✖  fatal\|Prism is listening" ".prism.log" ; do
-    echo -n "."
-    sleep 0.1
-  done
-
-  if grep -q "✖  fatal" ".prism.log"; then
-    cat .prism.log
-    exit 1
-  fi
-
-  echo
-else
-  npm exec --package=@stainless-api/prism-cli@5.15.0 -- prism mock "$URL"
-fi
diff --git a/scripts/test b/scripts/test
index 7bce051..548da9b 100755
--- a/scripts/test
+++ b/scripts/test
@@ -4,53 +4,7 @@ set -e
 
 cd "$(dirname "$0")/.."
 
-RED='\033[0;31m'
-GREEN='\033[0;32m'
-YELLOW='\033[0;33m'
-NC='\033[0m' # No Color
 
-function prism_is_running() {
-  curl --silent "http://localhost:4010" >/dev/null 2>&1
-}
-
-kill_server_on_port() {
-  pids=$(lsof -t -i tcp:"$1" || echo "")
-  if [ "$pids" != "" ]; then
-    kill "$pids"
-    echo "Stopped $pids."
-  fi
-}
-
-function is_overriding_api_base_url() {
-  [ -n "$TEST_API_BASE_URL" ]
-}
-
-if ! is_overriding_api_base_url && ! prism_is_running ; then
-  # When we exit this script, make sure to kill the background mock server process
-  trap 'kill_server_on_port 4010' EXIT
-
-  # Start the dev server
-  ./scripts/mock --daemon
-fi
-
-if is_overriding_api_base_url ; then
-  echo -e "${GREEN}✔ Running tests against ${TEST_API_BASE_URL}${NC}"
-  echo
-elif ! prism_is_running ; then
-  echo -e "${RED}ERROR:${NC} The test suite will not run without a mock Prism server"
-  echo -e "running against your OpenAPI spec."
-  echo
-  echo -e "To run the server, pass in the path or url of your OpenAPI"
-  echo -e "spec to the prism command:"
-  echo
-  echo -e "  \$ ${YELLOW}npm exec --package=@stainless-api/prism-cli@5.15.0 -- prism mock path/to/your.openapi.yml${NC}"
-  echo
-
-  exit 1
-else
-  echo -e "${GREEN}✔ Mock prism server is running with your OpenAPI spec${NC}"
-  echo
-fi
 
 echo "==> Running tests"
 ./node_modules/.bin/jest "$@"

From 32ba29c2431daee857b1a3eddc695e372cab3436 Mon Sep 17 00:00:00 2001
From: "stainless-app[bot]"
 <142633134+stainless-app[bot]@users.noreply.github.com>
Date: Fri, 20 Feb 2026 06:29:59 +0000
Subject: [PATCH 08/10] chore: update mock server docs

---
 CONTRIBUTING.md                               |  6 ------
 tests/api-resources/contacts/bulk.test.ts     |  8 ++++----
 tests/api-resources/contacts/contacts.test.ts | 20 +++++++++----------
 tests/api-resources/groups.test.ts            |  8 ++++----
 tests/api-resources/lookups.test.ts           |  4 ++--
 tests/api-resources/media-objects.test.ts     |  4 ++--
 tests/api-resources/messages.test.ts          | 14 ++++++-------
 tests/api-resources/typing-indicators.test.ts |  4 ++--
 tests/api-resources/webhooks.test.ts          | 14 ++++++-------
 9 files changed, 38 insertions(+), 44 deletions(-)

diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 38dc266..6dac594 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -65,12 +65,6 @@ $ pnpm link -—global sendblue
 
 ## Running tests
 
-Most tests require you to [set up a mock server](https://github.com/stoplightio/prism) against the OpenAPI spec to run the tests.
-
-```sh
-$ npx prism mock path/to/your/openapi.yml
-```
-
 ```sh
 $ yarn run test
 ```
diff --git a/tests/api-resources/contacts/bulk.test.ts b/tests/api-resources/contacts/bulk.test.ts
index c6ea79a..24d26db 100644
--- a/tests/api-resources/contacts/bulk.test.ts
+++ b/tests/api-resources/contacts/bulk.test.ts
@@ -9,7 +9,7 @@ const client = new SendblueAPI({
 });
 
 describe('resource bulk', () => {
-  // Prism tests are disabled
+  // Mock server tests are disabled
   test.skip('create: only required params', async () => {
     const responsePromise = client.contacts.bulk.create({ contacts: [{ phone: 'phone' }] });
     const rawResponse = await responsePromise.asResponse();
@@ -21,7 +21,7 @@ describe('resource bulk', () => {
     expect(dataAndResponse.response).toBe(rawResponse);
   });
 
-  // Prism tests are disabled
+  // Mock server tests are disabled
   test.skip('create: required and optional params', async () => {
     const response = await client.contacts.bulk.create({
       contacts: [
@@ -37,7 +37,7 @@ describe('resource bulk', () => {
     });
   });
 
-  // Prism tests are disabled
+  // Mock server tests are disabled
   test.skip('delete: only required params', async () => {
     const responsePromise = client.contacts.bulk.delete({ contact_ids: ['+1234567890', '+0987654321'] });
     const rawResponse = await responsePromise.asResponse();
@@ -49,7 +49,7 @@ describe('resource bulk', () => {
     expect(dataAndResponse.response).toBe(rawResponse);
   });
 
-  // Prism tests are disabled
+  // Mock server tests are disabled
   test.skip('delete: required and optional params', async () => {
     const response = await client.contacts.bulk.delete({ contact_ids: ['+1234567890', '+0987654321'] });
   });
diff --git a/tests/api-resources/contacts/contacts.test.ts b/tests/api-resources/contacts/contacts.test.ts
index 67dc6cc..b78eea3 100644
--- a/tests/api-resources/contacts/contacts.test.ts
+++ b/tests/api-resources/contacts/contacts.test.ts
@@ -9,7 +9,7 @@ const client = new SendblueAPI({
 });
 
 describe('resource contacts', () => {
-  // Prism tests are disabled
+  // Mock server tests are disabled
   test.skip('create: only required params', async () => {
     const responsePromise = client.contacts.create({ number: 'number' });
     const rawResponse = await responsePromise.asResponse();
@@ -21,7 +21,7 @@ describe('resource contacts', () => {
     expect(dataAndResponse.response).toBe(rawResponse);
   });
 
-  // Prism tests are disabled
+  // Mock server tests are disabled
   test.skip('create: required and optional params', async () => {
     const response = await client.contacts.create({
       number: 'number',
@@ -41,7 +41,7 @@ describe('resource contacts', () => {
     });
   });
 
-  // Prism tests are disabled
+  // Mock server tests are disabled
   test.skip('retrieve', async () => {
     const responsePromise = client.contacts.retrieve('+1234567890');
     const rawResponse = await responsePromise.asResponse();
@@ -53,7 +53,7 @@ describe('resource contacts', () => {
     expect(dataAndResponse.response).toBe(rawResponse);
   });
 
-  // Prism tests are disabled
+  // Mock server tests are disabled
   test.skip('update', async () => {
     const responsePromise = client.contacts.update('+1234567890', {});
     const rawResponse = await responsePromise.asResponse();
@@ -65,7 +65,7 @@ describe('resource contacts', () => {
     expect(dataAndResponse.response).toBe(rawResponse);
   });
 
-  // Prism tests are disabled
+  // Mock server tests are disabled
   test.skip('list', async () => {
     const responsePromise = client.contacts.list();
     const rawResponse = await responsePromise.asResponse();
@@ -77,7 +77,7 @@ describe('resource contacts', () => {
     expect(dataAndResponse.response).toBe(rawResponse);
   });
 
-  // Prism tests are disabled
+  // Mock server tests are disabled
   test.skip('list: request options and params are passed correctly', async () => {
     // ensure the request options are being passed correctly by passing an invalid HTTP method in order to cause an error
     await expect(
@@ -95,7 +95,7 @@ describe('resource contacts', () => {
     ).rejects.toThrow(SendblueAPI.NotFoundError);
   });
 
-  // Prism tests are disabled
+  // Mock server tests are disabled
   test.skip('delete', async () => {
     const responsePromise = client.contacts.delete('+1234567890');
     const rawResponse = await responsePromise.asResponse();
@@ -107,7 +107,7 @@ describe('resource contacts', () => {
     expect(dataAndResponse.response).toBe(rawResponse);
   });
 
-  // Prism tests are disabled
+  // Mock server tests are disabled
   test.skip('count', async () => {
     const responsePromise = client.contacts.count();
     const rawResponse = await responsePromise.asResponse();
@@ -119,7 +119,7 @@ describe('resource contacts', () => {
     expect(dataAndResponse.response).toBe(rawResponse);
   });
 
-  // Prism tests are disabled
+  // Mock server tests are disabled
   test.skip('verify: only required params', async () => {
     const responsePromise = client.contacts.verify({ number: 'number' });
     const rawResponse = await responsePromise.asResponse();
@@ -131,7 +131,7 @@ describe('resource contacts', () => {
     expect(dataAndResponse.response).toBe(rawResponse);
   });
 
-  // Prism tests are disabled
+  // Mock server tests are disabled
   test.skip('verify: required and optional params', async () => {
     const response = await client.contacts.verify({ number: 'number' });
   });
diff --git a/tests/api-resources/groups.test.ts b/tests/api-resources/groups.test.ts
index 3490307..9194e90 100644
--- a/tests/api-resources/groups.test.ts
+++ b/tests/api-resources/groups.test.ts
@@ -9,7 +9,7 @@ const client = new SendblueAPI({
 });
 
 describe('resource groups', () => {
-  // Prism tests are disabled
+  // Mock server tests are disabled
   test.skip('modify: only required params', async () => {
     const responsePromise = client.groups.modify({
       group_id: 'group_123456',
@@ -25,7 +25,7 @@ describe('resource groups', () => {
     expect(dataAndResponse.response).toBe(rawResponse);
   });
 
-  // Prism tests are disabled
+  // Mock server tests are disabled
   test.skip('modify: required and optional params', async () => {
     const response = await client.groups.modify({
       group_id: 'group_123456',
@@ -34,7 +34,7 @@ describe('resource groups', () => {
     });
   });
 
-  // Prism tests are disabled
+  // Mock server tests are disabled
   test.skip('sendMessage: only required params', async () => {
     const responsePromise = client.groups.sendMessage({
       content: 'Hello, everyone!',
@@ -49,7 +49,7 @@ describe('resource groups', () => {
     expect(dataAndResponse.response).toBe(rawResponse);
   });
 
-  // Prism tests are disabled
+  // Mock server tests are disabled
   test.skip('sendMessage: required and optional params', async () => {
     const response = await client.groups.sendMessage({
       content: 'Hello, everyone!',
diff --git a/tests/api-resources/lookups.test.ts b/tests/api-resources/lookups.test.ts
index 10705e6..d03ba83 100644
--- a/tests/api-resources/lookups.test.ts
+++ b/tests/api-resources/lookups.test.ts
@@ -9,7 +9,7 @@ const client = new SendblueAPI({
 });
 
 describe('resource lookups', () => {
-  // Prism tests are disabled
+  // Mock server tests are disabled
   test.skip('lookupNumber: only required params', async () => {
     const responsePromise = client.lookups.lookupNumber({ number: '+19999999999' });
     const rawResponse = await responsePromise.asResponse();
@@ -21,7 +21,7 @@ describe('resource lookups', () => {
     expect(dataAndResponse.response).toBe(rawResponse);
   });
 
-  // Prism tests are disabled
+  // Mock server tests are disabled
   test.skip('lookupNumber: required and optional params', async () => {
     const response = await client.lookups.lookupNumber({ number: '+19999999999' });
   });
diff --git a/tests/api-resources/media-objects.test.ts b/tests/api-resources/media-objects.test.ts
index 0ba6e00..97f68c2 100644
--- a/tests/api-resources/media-objects.test.ts
+++ b/tests/api-resources/media-objects.test.ts
@@ -9,7 +9,7 @@ const client = new SendblueAPI({
 });
 
 describe('resource mediaObjects', () => {
-  // Prism tests are disabled
+  // Mock server tests are disabled
   test.skip('upload: only required params', async () => {
     const responsePromise = client.mediaObjects.upload({ media_url: 'https://example.com/image.jpg' });
     const rawResponse = await responsePromise.asResponse();
@@ -21,7 +21,7 @@ describe('resource mediaObjects', () => {
     expect(dataAndResponse.response).toBe(rawResponse);
   });
 
-  // Prism tests are disabled
+  // Mock server tests are disabled
   test.skip('upload: required and optional params', async () => {
     const response = await client.mediaObjects.upload({ media_url: 'https://example.com/image.jpg' });
   });
diff --git a/tests/api-resources/messages.test.ts b/tests/api-resources/messages.test.ts
index c356867..92a4452 100644
--- a/tests/api-resources/messages.test.ts
+++ b/tests/api-resources/messages.test.ts
@@ -9,7 +9,7 @@ const client = new SendblueAPI({
 });
 
 describe('resource messages', () => {
-  // Prism tests are disabled
+  // Mock server tests are disabled
   test.skip('retrieve', async () => {
     const responsePromise = client.messages.retrieve('msg_abc123def456');
     const rawResponse = await responsePromise.asResponse();
@@ -21,7 +21,7 @@ describe('resource messages', () => {
     expect(dataAndResponse.response).toBe(rawResponse);
   });
 
-  // Prism tests are disabled
+  // Mock server tests are disabled
   test.skip('list', async () => {
     const responsePromise = client.messages.list();
     const rawResponse = await responsePromise.asResponse();
@@ -33,7 +33,7 @@ describe('resource messages', () => {
     expect(dataAndResponse.response).toBe(rawResponse);
   });
 
-  // Prism tests are disabled
+  // Mock server tests are disabled
   test.skip('list: request options and params are passed correctly', async () => {
     // ensure the request options are being passed correctly by passing an invalid HTTP method in order to cause an error
     await expect(
@@ -66,7 +66,7 @@ describe('resource messages', () => {
     ).rejects.toThrow(SendblueAPI.NotFoundError);
   });
 
-  // Prism tests are disabled
+  // Mock server tests are disabled
   test.skip('getStatus: only required params', async () => {
     const responsePromise = client.messages.getStatus({ handle: 'msg_abc123def456' });
     const rawResponse = await responsePromise.asResponse();
@@ -78,12 +78,12 @@ describe('resource messages', () => {
     expect(dataAndResponse.response).toBe(rawResponse);
   });
 
-  // Prism tests are disabled
+  // Mock server tests are disabled
   test.skip('getStatus: required and optional params', async () => {
     const response = await client.messages.getStatus({ handle: 'msg_abc123def456' });
   });
 
-  // Prism tests are disabled
+  // Mock server tests are disabled
   test.skip('send: only required params', async () => {
     const responsePromise = client.messages.send({
       content: 'Hello, World!',
@@ -99,7 +99,7 @@ describe('resource messages', () => {
     expect(dataAndResponse.response).toBe(rawResponse);
   });
 
-  // Prism tests are disabled
+  // Mock server tests are disabled
   test.skip('send: required and optional params', async () => {
     const response = await client.messages.send({
       content: 'Hello, World!',
diff --git a/tests/api-resources/typing-indicators.test.ts b/tests/api-resources/typing-indicators.test.ts
index 8af1182..8cb4e78 100644
--- a/tests/api-resources/typing-indicators.test.ts
+++ b/tests/api-resources/typing-indicators.test.ts
@@ -9,7 +9,7 @@ const client = new SendblueAPI({
 });
 
 describe('resource typingIndicators', () => {
-  // Prism tests are disabled
+  // Mock server tests are disabled
   test.skip('send: only required params', async () => {
     const responsePromise = client.typingIndicators.send({
       from_number: '+16292925296',
@@ -24,7 +24,7 @@ describe('resource typingIndicators', () => {
     expect(dataAndResponse.response).toBe(rawResponse);
   });
 
-  // Prism tests are disabled
+  // Mock server tests are disabled
   test.skip('send: required and optional params', async () => {
     const response = await client.typingIndicators.send({
       from_number: '+16292925296',
diff --git a/tests/api-resources/webhooks.test.ts b/tests/api-resources/webhooks.test.ts
index c666a0d..e0b127b 100644
--- a/tests/api-resources/webhooks.test.ts
+++ b/tests/api-resources/webhooks.test.ts
@@ -9,7 +9,7 @@ const client = new SendblueAPI({
 });
 
 describe('resource webhooks', () => {
-  // Prism tests are disabled
+  // Mock server tests are disabled
   test.skip('create: only required params', async () => {
     const responsePromise = client.webhooks.create({ webhooks: ['https://example.com'] });
     const rawResponse = await responsePromise.asResponse();
@@ -21,7 +21,7 @@ describe('resource webhooks', () => {
     expect(dataAndResponse.response).toBe(rawResponse);
   });
 
-  // Prism tests are disabled
+  // Mock server tests are disabled
   test.skip('create: required and optional params', async () => {
     const response = await client.webhooks.create({
       webhooks: ['https://example.com'],
@@ -30,7 +30,7 @@ describe('resource webhooks', () => {
     });
   });
 
-  // Prism tests are disabled
+  // Mock server tests are disabled
   test.skip('update: only required params', async () => {
     const responsePromise = client.webhooks.update({ webhooks: {} });
     const rawResponse = await responsePromise.asResponse();
@@ -42,7 +42,7 @@ describe('resource webhooks', () => {
     expect(dataAndResponse.response).toBe(rawResponse);
   });
 
-  // Prism tests are disabled
+  // Mock server tests are disabled
   test.skip('update: required and optional params', async () => {
     const response = await client.webhooks.update({
       webhooks: {
@@ -58,7 +58,7 @@ describe('resource webhooks', () => {
     });
   });
 
-  // Prism tests are disabled
+  // Mock server tests are disabled
   test.skip('list', async () => {
     const responsePromise = client.webhooks.list();
     const rawResponse = await responsePromise.asResponse();
@@ -70,7 +70,7 @@ describe('resource webhooks', () => {
     expect(dataAndResponse.response).toBe(rawResponse);
   });
 
-  // Prism tests are disabled
+  // Mock server tests are disabled
   test.skip('delete: only required params', async () => {
     const responsePromise = client.webhooks.delete({ webhooks: ['https://example.com'] });
     const rawResponse = await responsePromise.asResponse();
@@ -82,7 +82,7 @@ describe('resource webhooks', () => {
     expect(dataAndResponse.response).toBe(rawResponse);
   });
 
-  // Prism tests are disabled
+  // Mock server tests are disabled
   test.skip('delete: required and optional params', async () => {
     const response = await client.webhooks.delete({ webhooks: ['https://example.com'], type: 'receive' });
   });

From 45a3ed52cc155a8be91982997764f5dda2987052 Mon Sep 17 00:00:00 2001
From: "stainless-app[bot]"
 <142633134+stainless-app[bot]@users.noreply.github.com>
Date: Fri, 20 Feb 2026 06:39:55 +0000
Subject: [PATCH 09/10] chore(mcp): correctly update version in sync with sdk

---
 release-please-config.json | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/release-please-config.json b/release-please-config.json
index b190980..9b04279 100644
--- a/release-please-config.json
+++ b/release-please-config.json
@@ -68,6 +68,11 @@
       "type": "json",
       "path": "packages/mcp-server/package.json",
       "jsonpath": "$.version"
+    },
+    {
+      "type": "json",
+      "path": "packages/mcp-server/manifest.json",
+      "jsonpath": "$.version"
     }
   ]
 }

From 60de51dc622bcd0a90fd2f4d16be5c962b2ebb97 Mon Sep 17 00:00:00 2001
From: "stainless-app[bot]"
 <142633134+stainless-app[bot]@users.noreply.github.com>
Date: Fri, 20 Feb 2026 06:40:14 +0000
Subject: [PATCH 10/10] release: 3.1.2

---
 .release-please-manifest.json     |  2 +-
 CHANGELOG.md                      | 20 ++++++++++++++++++++
 package.json                      |  2 +-
 packages/mcp-server/manifest.json | 10 +++++++---
 packages/mcp-server/package.json  |  2 +-
 packages/mcp-server/src/server.ts |  2 +-
 src/version.ts                    |  2 +-
 7 files changed, 32 insertions(+), 8 deletions(-)

diff --git a/.release-please-manifest.json b/.release-please-manifest.json
index b4b8d0f..50d9d3b 100644
--- a/.release-please-manifest.json
+++ b/.release-please-manifest.json
@@ -1,3 +1,3 @@
 {
-  ".": "3.1.1"
+  ".": "3.1.2"
 }
diff --git a/CHANGELOG.md b/CHANGELOG.md
index d2bf9c0..1953329 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,25 @@
 # Changelog
 
+## 3.1.2 (2026-02-20)
+
+Full Changelog: [v3.1.1...v3.1.2](https://github.com/sendblue-api/sendblue-ts/compare/v3.1.1...v3.1.2)
+
+### Bug Fixes
+
+* **mcp:** initialize SDK lazily to avoid failing the connection on init errors ([0b99f69](https://github.com/sendblue-api/sendblue-ts/commit/0b99f6924a49cdc17d09e5cdac932130f5b22a13))
+
+
+### Chores
+
+* **internal/client:** fix form-urlencoded requests ([0636408](https://github.com/sendblue-api/sendblue-ts/commit/06364085dd59f4b43b2f0f95b8bab83435fa9ffb))
+* **internal:** allow setting x-stainless-api-key header on mcp server requests ([cdbf955](https://github.com/sendblue-api/sendblue-ts/commit/cdbf955893b151aa89778d292b3e041a476e0306))
+* **internal:** cache fetch instruction calls in MCP server ([3c55910](https://github.com/sendblue-api/sendblue-ts/commit/3c5591018ee53d8e51d94100f6cafa0c02572046))
+* **internal:** improve layout of generated MCP server files ([01a4563](https://github.com/sendblue-api/sendblue-ts/commit/01a45632c1ee8e9eec2a3995a1b7891059d1b101))
+* **internal:** remove mock server code ([f322a40](https://github.com/sendblue-api/sendblue-ts/commit/f322a40ea28a1b9251b0e296ef7ab92a6c8d7888))
+* **mcp:** correctly update version in sync with sdk ([45a3ed5](https://github.com/sendblue-api/sendblue-ts/commit/45a3ed52cc155a8be91982997764f5dda2987052))
+* **mcp:** forward STAINLESS_API_KEY to docs search endpoint ([869a8aa](https://github.com/sendblue-api/sendblue-ts/commit/869a8aa557dfae546e648a5d92e86432703c2cff))
+* update mock server docs ([32ba29c](https://github.com/sendblue-api/sendblue-ts/commit/32ba29c2431daee857b1a3eddc695e372cab3436))
+
 ## 3.1.1 (2026-02-12)
 
 Full Changelog: [v3.1.0...v3.1.1](https://github.com/sendblue-api/sendblue-ts/compare/v3.1.0...v3.1.1)
diff --git a/package.json b/package.json
index 749312f..fe8f2dc 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "sendblue",
-  "version": "3.1.1",
+  "version": "3.1.2",
   "description": "The official TypeScript library for the Sendblue API API",
   "author": "Sendblue API <support@sendblue.co>",
   "types": "dist/index.d.ts",
diff --git a/packages/mcp-server/manifest.json b/packages/mcp-server/manifest.json
index 8c0b431..a7bfac2 100644
--- a/packages/mcp-server/manifest.json
+++ b/packages/mcp-server/manifest.json
@@ -1,7 +1,7 @@
 {
   "dxt_version": "0.2",
   "name": "sendblue-mcp",
-  "version": "2.0.1",
+  "version": "3.1.2",
   "description": "The official MCP Server for the Sendblue API API",
   "author": {
     "name": "Sendblue API",
@@ -18,7 +18,9 @@
     "entry_point": "index.js",
     "mcp_config": {
       "command": "node",
-      "args": ["${__dirname}/index.js"],
+      "args": [
+        "${__dirname}/index.js"
+      ],
       "env": {
         "SENDBLUE_API_API_KEY": "${user_config.SENDBLUE_API_API_KEY}",
         "SENDBLUE_API_API_SECRET": "${user_config.SENDBLUE_API_API_SECRET}"
@@ -46,5 +48,7 @@
       "node": ">=18.0.0"
     }
   },
-  "keywords": ["api"]
+  "keywords": [
+    "api"
+  ]
 }
diff --git a/packages/mcp-server/package.json b/packages/mcp-server/package.json
index 5c9e84d..9a093e8 100644
--- a/packages/mcp-server/package.json
+++ b/packages/mcp-server/package.json
@@ -1,6 +1,6 @@
 {
   "name": "sendblue-mcp",
-  "version": "3.1.1",
+  "version": "3.1.2",
   "description": "The official MCP Server for the Sendblue API API",
   "author": "Sendblue API <support@sendblue.co>",
   "types": "dist/index.d.ts",
diff --git a/packages/mcp-server/src/server.ts b/packages/mcp-server/src/server.ts
index 14a1a13..1f460e6 100644
--- a/packages/mcp-server/src/server.ts
+++ b/packages/mcp-server/src/server.ts
@@ -20,7 +20,7 @@ export const newMcpServer = async (stainlessApiKey: string | undefined) =>
   new McpServer(
     {
       name: 'sendblue_api',
-      version: '3.1.1',
+      version: '3.1.2',
     },
     {
       instructions: await getInstructions(stainlessApiKey),
diff --git a/src/version.ts b/src/version.ts
index 6883c1e..0716f80 100644
--- a/src/version.ts
+++ b/src/version.ts
@@ -1 +1 @@
-export const VERSION = '3.1.1'; // x-release-please-version
+export const VERSION = '3.1.2'; // x-release-please-version