Package Reference

@delta-mcp/server

Build Delta-MCP servers.

npm install @delta-mcp/server

DeltaServer

import { DeltaServer } from "@delta-mcp/server";

class MyServer extends DeltaServer {
  constructor() {
    super({
      name: "my-server",
      version: "1.0.0",
      resultHandler: {
        maxTokens: 2000,     // truncate strings over ~2000 tokens
        paginateAfter: 50,   // paginate arrays over 50 items
      },
    });

    this.tool({
      name: "search",
      description: "Search docs and return top results",  // ≤60 chars
      inputSchema: { /* JSON Schema */ },
    });
  }

  protected async callTool(name: string, args: unknown): Promise<unknown> {
    // your tool logic here
  }
}

// stdio (Claude Desktop, agents)
new MyServer().startStdio();

// HTTP
new MyServer().startHttp({ port: 3000 });

// HTTP + OAuth 2.1
new MyServer().startHttp({
  port: 3000,
  oauth: {
    resourceUrl: "https://mcp.example.com",
    authorizationServers: ["https://auth.example.com"],
    verifySignature: async (token) => verify(token),
  },
});

Constructor options

Option	Type	Default	Description
name	string	required	Server name returned in initialize
version	string	required	Server version
resultHandler.maxTokens	number	4000	Token budget before string/object truncation
resultHandler.paginateAfter	number	100	Array length threshold for pagination

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@delta-mcp/client

Connect to Delta-MCP (and standard MCP) servers.

npm install @delta-mcp/client

DeltaClient

import { DeltaClient, StdioClientTransport, HttpClientTransport } from "@delta-mcp/client";

// stdio
const transport = new StdioClientTransport("node", ["server.js"]);

// HTTP
const transport = new HttpClientTransport("http://localhost:3000");

// HTTP + auth
const transport = new HttpClientTransport("http://localhost:3000", {
  headers: { Authorization: `Bearer ${token}` },
});

const client = new DeltaClient(transport);
await client.initialize({ name: "my-client", version: "1.0.0" });

// Progressive disclosure: names + descriptions only
const tools = await client.listTools();

// On-demand schema (cached after first fetch)
const schema = await client.describeTool("search");

// Call a tool (fetches schema if needed)
const result = await client.callTool("search", { query: "hello" });

// Session info
console.log(client.sessionInfo.progressiveDisclosure);  // true/false
console.log(client.sessionInfo.encoding);               // "compact-json" | "json"

transport.close();

StdioClientTransport

new StdioClientTransport(command: string, args?: string[])

Spawns command as a child process. Uses newline-delimited JSON-RPC over stdin/stdout.

HttpClientTransport

new HttpClientTransport(url: string, options?: { headers?: Record<string, string> })

Connects to a Streamable HTTP MCP server. Supports OAuth via Authorization header.

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@delta-mcp/core

Low-level protocol types, transport primitives, and result handler utilities. Consumed by server and client — you rarely import this directly.

npm install @delta-mcp/core

Result handler utilities

import { handleToolResult, detectAndHandleRateLimit } from "@delta-mcp/core";

// Apply truncation + pagination to a result
const handled = handleToolResult(rawResult, { maxTokens: 2000, paginateAfter: 50 });

// Convert a 429 error into a structured result
const safe = detectAndHandleRateLimit(error, "tool_name");

Benchmark utilities

import { benchmarkToolDiscovery, formatBenchmark, estimateTokens } from "@delta-mcp/core/benchmark";

const schemas = [...]; // array of full tool schemas
const result = benchmarkToolDiscovery(schemas);
console.log(formatBenchmark([result]));

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@delta-mcp/cli

CLI for inspecting and benchmarking servers. See CLI Reference.

npm install -g @delta-mcp/cli