{"title":"Build a Custom MCP Client","slug":"custom-client","category":"mcp","summary":"Connect to the Synapse MCP server from your own application using the MCP SDK.","audience":["human","llm"],"tags":["mcp","custom","sdk","development"],"difficulty":"advanced","updated":"2026-06-27","word_count":157,"read_minutes":1,"lang":"en","translated":true,"requested_lang":"en","content_markdown":"\n# Build a Custom MCP Client\n\nIf you're building your own LLM application, you can connect to the Synapse\nMCP server directly using the official MCP SDK. This gives your app access to\nall 79 Synapse tools.\n\n## SDKs\n\n| Language | Package |\n|----------|---------|\n| TypeScript/JavaScript | `@modelcontextprotocol/sdk` |\n| Python | `mcp` |\n\n## TypeScript Example\n\n### Install\n\n```bash\nnpm install @modelcontextprotocol/sdk\n```\n\n### Connect via stdio\n\n```typescript\nimport { Client } from \"@modelcontextprotocol/sdk/client/index.js\";\nimport { StdioClientTransport } from \"@modelcontextprotocol/sdk/client/stdio.js\";\n\nconst transport = new StdioClientTransport({\n command: \"npx\",\n args: [\"-y\", \"synapse-mcp-api@latest\"],\n env: {\n SYNAPSE_MIND_KEY: process.env.SYNAPSE_MIND_KEY!,\n SYNAPSE_URL: \"https://synapse.schaefer.zone\",\n },\n});\n\nconst client = new Client(\n { name: \"my-app\", version: \"1.0.0\" },\n { capabilities: {} }\n);\n\nawait client.connect(transport);\n\n// List all available tools\nconst { tools } = await client.listTools();\nconsole.log(`Available tools: ${tools.length}`);\nfor (const tool of tools) {\n console.log(`- ${tool.name}: ${tool.description}`);\n}\n\n// Call a tool\nconst result = await client.callTool({\n name: \"memory_recall\",\n arguments: {},\n});\nconsole.log(result.content);\n\n// Store a memory\nawait client.callTool({\n name: \"memory_store\",\n arguments: {\n category: \"fact\",\n key: \"custom_client_test\",\n content: \"Built a custom MCP client\",\n tags: [\"test\", \"mcp\"],\n priority: \"normal\",\n },\n});\n\nawait client.close();\n```\n\n### Connect via HTTP/SSE (remote)\n\n```typescript\nimport { Client } from \"@modelcontextprotocol/sdk/client/index.js\";\nimport { SSEClientTransport } from \"@modelcontextprotocol/sdk/client/sse.js\";\n\nconst transport = new SSEClientTransport(\n new URL(\"https://synapse-mcp.schaefer.zone/sse\"),\n {\n requestInit: {\n headers: {\n Authorization: `Bearer ${process.env.SYNAPSE_MIND_KEY}`,\n },\n },\n }\n);\n\nconst client = new Client(\n { name: \"my-app\", version: \"1.0.0\" },\n { capabilities: {} }\n);\n\nawait client.connect(transport);\n// ... use as above\n```\n\n## Python Example\n\n### Install\n\n```bash\npip install mcp\n```\n\n### Connect via stdio\n\n```python\nfrom mcp import ClientSession, StdioServerParameters\nfrom mcp.client.stdio import stdio_client\n\nserver_params = StdioServerParameters(\n command=\"npx\",\n args=[\"-y\", \"synapse-mcp-api@latest\"],\n env={\n \"SYNAPSE_MIND_KEY\": \"mk_YOUR_KEY\",\n \"SYNAPSE_URL\": \"https://synapse.schaefer.zone\",\n },\n)\n\nasync with stdio_client(server_params) as (read, write):\n async with ClientSession(read, write) as session:\n await session.initialize()\n\n # List tools\n tools = await session.list_tools()\n print(f\"Available tools: {len(tools.tools)}\")\n\n # Call a tool\n result = await session.call_tool(\"memory_recall\", {})\n print(result.content)\n\n # Store a memory\n await session.call_tool(\"memory_store\", {\n \"category\": \"fact\",\n \"key\": \"python_client_test\",\n \"content\": \"Built a Python MCP client\",\n \"tags\": [\"test\", \"mcp\", \"python\"],\n \"priority\": \"normal\",\n })\n```\n\n## Tool Profiles\n\nWhen connecting, you can request a specific tool profile via the\n`Mcp-Tool-Profile` header (HTTP/SSE) or `MCP_PROFILE` env var (stdio):\n\n```typescript\n// stdio: set env var\nenv: {\n SYNAPSE_MIND_KEY: \"mk_...\",\n MCP_PROFILE: \"minimal\", // 8 tools instead of 119\n}\n\n// HTTP/SSE: set header\nrequestInit: {\n headers: {\n Authorization: \"Bearer mk_...\",\n \"Mcp-Tool-Profile\": \"minimal\",\n },\n}\n```\n\n## Error Handling\n\n```typescript\ntry {\n const result = await client.callTool({ name: \"memory_recall\", arguments: {} });\n if (result.isError) {\n console.error(\"Tool error:\", result.content);\n } else {\n console.log(\"Success:\", result.content);\n }\n} catch (err) {\n console.error(\"MCP error:\", err);\n}\n```\n\n## Use Cases\n\n- **Custom AI assistants** — build your own agent with persistent memory\n- **Workflow automation** — chain Synapse tools in custom workflows\n- **Data pipelines** — extract memories, transform, load elsewhere\n- **Monitoring dashboards** — display memory stats, chat history, tasks\n\n## Next Steps\n\n- [MCP Specification](https://spec.modelcontextprotocol.io)\n- [Synapse MCP Repo](https://gitlab.com/schaefer-services/synapse-mcp)\n- [API Overview](/docs/api/overview)\n","content_html":"

Build a Custom MCP Client

\n

If you're building your own LLM application, you can connect to the Synapse\nMCP server directly using the official MCP SDK. This gives your app access to\nall 79 Synapse tools.

\n

SDKs

\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n
LanguagePackage
TypeScript/JavaScript@modelcontextprotocol/sdk
Pythonmcp
\n

TypeScript Example

\n

Install

\n
npm install @modelcontextprotocol/sdk

Connect via stdio

\n
import { Client } from "@modelcontextprotocol/sdk/client/index.js";\nimport { StdioClientTransport } from "@modelcontextprotocol/sdk/client/stdio.js";\n\nconst transport = new StdioClientTransport({\n  command: "npx",\n  args: ["-y", "synapse-mcp-api@latest"],\n  env: {\n    SYNAPSE_MIND_KEY: process.env.SYNAPSE_MIND_KEY!,\n    SYNAPSE_URL: "https://synapse.schaefer.zone",\n  },\n});\n\nconst client = new Client(\n  { name: "my-app", version: "1.0.0" },\n  { capabilities: {} }\n);\n\nawait client.connect(transport);\n\n// List all available tools\nconst { tools } = await client.listTools();\nconsole.log(`Available tools: ${tools.length}`);\nfor (const tool of tools) {\n  console.log(`- ${tool.name}: ${tool.description}`);\n}\n\n// Call a tool\nconst result = await client.callTool({\n  name: "memory_recall",\n  arguments: {},\n});\nconsole.log(result.content);\n\n// Store a memory\nawait client.callTool({\n  name: "memory_store",\n  arguments: {\n    category: "fact",\n    key: "custom_client_test",\n    content: "Built a custom MCP client",\n    tags: ["test", "mcp"],\n    priority: "normal",\n  },\n});\n\nawait client.close();

Connect via HTTP/SSE (remote)

\n
import { Client } from "@modelcontextprotocol/sdk/client/index.js";\nimport { SSEClientTransport } from "@modelcontextprotocol/sdk/client/sse.js";\n\nconst transport = new SSEClientTransport(\n  new URL("https://synapse-mcp.schaefer.zone/sse"),\n  {\n    requestInit: {\n      headers: {\n        Authorization: `Bearer ${process.env.SYNAPSE_MIND_KEY}`,\n      },\n    },\n  }\n);\n\nconst client = new Client(\n  { name: "my-app", version: "1.0.0" },\n  { capabilities: {} }\n);\n\nawait client.connect(transport);\n// ... use as above

Python Example

\n

Install

\n
pip install mcp

Connect via stdio

\n
from mcp import ClientSession, StdioServerParameters\nfrom mcp.client.stdio import stdio_client\n\nserver_params = StdioServerParameters(\n    command="npx",\n    args=["-y", "synapse-mcp-api@latest"],\n    env={\n        "SYNAPSE_MIND_KEY": "mk_YOUR_KEY",\n        "SYNAPSE_URL": "https://synapse.schaefer.zone",\n    },\n)\n\nasync with stdio_client(server_params) as (read, write):\n    async with ClientSession(read, write) as session:\n        await session.initialize()\n\n        # List tools\n        tools = await session.list_tools()\n        print(f"Available tools: {len(tools.tools)}")\n\n        # Call a tool\n        result = await session.call_tool("memory_recall", {})\n        print(result.content)\n\n        # Store a memory\n        await session.call_tool("memory_store", {\n            "category": "fact",\n            "key": "python_client_test",\n            "content": "Built a Python MCP client",\n            "tags": ["test", "mcp", "python"],\n            "priority": "normal",\n        })

Tool Profiles

\n

When connecting, you can request a specific tool profile via the\nMcp-Tool-Profile header (HTTP/SSE) or MCP_PROFILE env var (stdio):

\n
// stdio: set env var\nenv: {\n  SYNAPSE_MIND_KEY: "mk_...",\n  MCP_PROFILE: "minimal",  // 8 tools instead of 119\n}\n\n// HTTP/SSE: set header\nrequestInit: {\n  headers: {\n    Authorization: "Bearer mk_...",\n    "Mcp-Tool-Profile": "minimal",\n  },\n}

Error Handling

\n
try {\n  const result = await client.callTool({ name: "memory_recall", arguments: {} });\n  if (result.isError) {\n    console.error("Tool error:", result.content);\n  } else {\n    console.log("Success:", result.content);\n  }\n} catch (err) {\n  console.error("MCP error:", err);\n}

Use Cases

\n\n

Next Steps

\n\n","urls":{"html":"/docs/mcp/custom-client","text":"/docs/mcp/custom-client?format=text","json":"/docs/mcp/custom-client?format=json","llm":"/docs/mcp/custom-client?format=llm"},"translations_available":["en","zh","hi","es","fr","ar","pt","ru","ja","de","it","ko","nl","pl","tr","sv","vi","th","id","uk"]}