@truealter/sdk

@truealter/sdk

ALTER Identity SDK — query the continuous identity field from any JavaScript/TypeScript environment.

Install: npm install @truealter/sdkPublish channel: this repository is the public source mirror of the SDK that ships as @truealter/sdk on npm. The canonical build + publish flow lives in ALTER's monorepo — PRs and issues are welcome here; upstream sync happens on each tagged release.

A thin client over the ALTER MCP server (Streamable HTTP, JSON-RPC 2.0, MCP spec 2025-11-25) with x402 micropayment support, ES256 provenance verification, and config generators for Claude Code, Cursor, and generic MCP clients.

• Live MCP endpoint: https://mcp.truealter.com
• Wire protocol: Streamable HTTP, JSON-RPC 2.0, MCP 2025-11-25 (server negotiates 2025-06-18 + 2025-03-26 for backwards-compatible clients)
• Tools: 37 total — 25 free (L0) + 12 premium (L1–L5)
• Runtime: Node 18+, Deno, Bun, Cloudflare Workers, modern browsers
• Crypto: @noble/ed25519 + @noble/hashes (no other dependencies)
• Bundle: ESM + CJS dual output

Quickstart

npm install @truealter/sdk
npx alter-identity init
npx alter-identity verify ~truealter

Why ALTER ≠ IAM

Identity Access Management answers who is logged in. ALTER answers who they actually are — a continuous field of recognition (Paper VIII, Theorem 1) that any IAM stack can sit on top of.

Reference: Morrison, B. (2026). Identity Field Theory: A Continuous Field Model of Recognition. Figshare. DOI 10.6084/m9.figshare.31951383

API

Initialise the client

import { AlterClient, X402Client } from "@truealter/sdk";

const alter = new AlterClient({
  endpoint: "https://mcp.truealter.com", // optional — defaults to mcp.truealter.com
  apiKey: process.env.ALTER_API_KEY,     // optional for free tier
  x402: new X402Client({                  // optional — only required for premium tools
    signer: yourViemOrEthersSigner,
    maxPerQuery: "0.10",
  }),
});

Free tier (L0 — no payment required)

// Verify a registered identity by handle, email, or id
const verified = await alter.verify("~truealter");
const verifiedById = await alter.verify(
  "550e8400-e29b-41d4-a716-446655440000",
  {
    archetype: "weaver",
    min_engagement_level: 3,
    traits: { pressure_response: { min: 0.6 } },
  },
);

// Reference data — the 12 ALTER archetypes
const archetypes = await alter.listArchetypes();

// Identity depth and available tool tiers
const depth = await alter.getEngagementLevel({
  candidate_id: "550e8400-e29b-41d4-a716-446655440000",
});

// Search by trait criteria — no PII exposed, max 5 results
const matches = await alter.searchIdentities({
  trait_criteria: {
    pressure_response: { min: 0.7 },
    cognitive_flexibility: { min: 0.6 },
  },
});

// Golden Thread program status
const thread = await alter.goldenThreadStatus();

Premium tier (L1–L5 — x402 payment required)

// L1 — Extract trait signals from text ($0.005, first 100 free per bot)
const signals = await alter.assessTraits({
  text: "I led the incident response when our payment rails went down...",
  context: "interview transcript",
});

// L2 — Full 33-trait vector ($0.01)
const vector = await alter.getFullTraitVector({
  candidate_id: "550e8400-e29b-41d4-a716-446655440000",
});

// L4 — Belonging probability for a person-job pairing ($0.05)
const belonging = await alter.computeBelonging({
  candidate_id: "550e8400-e29b-41d4-a716-446655440000",
  job_id: "f47ac10b-58cc-4372-a567-0e02b2c3d479",
});

// L5 — Top match recommendations ($0.50)
const recommendations = await alter.getMatchRecommendations({
  candidate_id: "550e8400-e29b-41d4-a716-446655440000",
  limit: 5,
});

// L5 — Human-readable narrative explaining a match ($0.50)
const narrative = await alter.generateMatchNarrative({
  match_id: "9b1deb4d-3b7d-4bad-9bdd-2b0d7b3dcb6d",
});

Provenance verification

// Every medium- and high-blast-radius response is signed with ES256.
// Verification is opt-in — call alter.verifyProvenance(...) yourself.
const result = await alter.getFullTraitVector({
  candidate_id: "550e8400-e29b-41d4-a716-446655440000",
});

const check = await alter.verifyProvenance(result._meta?.provenance);
if (!check.valid) throw new Error(`provenance failed: ${check.reason}`);

// Verify that schema hashes published in tools/list._meta.signatures
// match the local representation of each tool.
const tools = await alter.mcp.listTools();
const sigs = tools._meta?.signatures ?? {};
const results = await alter.verifyToolSignatures(tools.tools, sigs);
const tampered = results.filter((r) => !r.valid);
if (tampered.length) throw new Error(`tampered tools: ${tampered.map((t) => t.tool).join(", ")}`);

Discovery

import { discover } from "@truealter/sdk";

// Three-step discovery cascade: DNS TXT → mcp.json → alter.json
const descriptor = await discover("truealter.com");
// → { url: "https://mcp.truealter.com", transport, source, publicKey, x402Contract, capability }

Low-level MCPClient

import { MCPClient } from "@truealter/sdk";

const mcp = new MCPClient({ endpoint: "https://mcp.truealter.com" });
await mcp.initialize();
const tools = await mcp.listTools();
const response = await mcp.callTool("verify_identity", {
  candidate_id: "550e8400-e29b-41d4-a716-446655440000",
});

MCP Config Generation

The SDK ships config generators for the major MCP-aware clients. Each emits a JSON snippet you can paste (or write directly) into the appropriate file.

Claude Code (.mcp.json)

import { generateClaudeConfig } from "@truealter/sdk";
import { writeFileSync } from "node:fs";

const config = generateClaudeConfig({
  endpoint: "https://mcp.truealter.com",
  apiKey: process.env.ALTER_API_KEY,
});

writeFileSync(".mcp.json", JSON.stringify(config, null, 2));

Resulting .mcp.json:

{
  "mcpServers": {
    "alter": {
      "url": "https://mcp.truealter.com",
      "transport": "streamable-http",
      "description": "ALTER Identity — psychometric identity field for AI agents",
      "headers": {
        "X-ALTER-API-Key": "ak_..."
      }
    }
  }
}

Cursor (.cursor/mcp.json)

import { generateCursorConfig } from "@truealter/sdk";
import { writeFileSync } from "node:fs";

const config = generateCursorConfig({
  endpoint: "https://mcp.truealter.com",
  apiKey: process.env.ALTER_API_KEY,
});

writeFileSync(".cursor/mcp.json", JSON.stringify(config, null, 2));

Generic MCP client

import { generateGenericMcpConfig } from "@truealter/sdk";

const config = generateGenericMcpConfig({
  endpoint: "https://mcp.truealter.com",
  apiKey: process.env.ALTER_API_KEY,
  serverName: "alter", // editor-specific key under mcpServers
});

CLI

npx alter-identity init               # generate keypair, discover MCP, write ~/.config/alter/identity.json
npx alter-identity config              # print Claude .mcp.json snippet (default)
npx alter-identity config --cursor     # print Cursor .cursor/mcp.json snippet
npx alter-identity config --generic    # print generic mcpServers snippet
npx alter-identity verify ~truealter   # verify an identity
npx alter-identity status              # show connection state and probe the endpoint

x402 Micropayments

ALTER monetises premium tools via the x402 standard — HTTP 402 Payment Required with on-chain settlement.

The retry flow

1. Client calls a premium tool without a payment header.
2. Server replies 402 Payment Required with a payment requirement (amount, recipient, asset, network).
3. Client signs and broadcasts a USDC transfer on Base L2, attaches the proof, retries.
4. Server validates the proof, executes the tool, signs the response with ES256, returns it.
5. The treasury splits the payment within seconds.

The SDK handles steps 2–4 automatically when an X402Client with a configured signer is passed in.

Tier structure

The first 100 calls per bot are free before x402 settlement engages — enough to evaluate the network without spending a cent.

Identity income split

Every settled call is split four ways:

The 75% to the data subject is the foundation of Identity Income — humans earn from queries against their own identity field, automatically, without intermediation.

Code example

import { AlterClient, X402Client, type X402Signer } from "@truealter/sdk";

// Bring your own signer — viem, ethers, a hardware wallet bridge, anything.
// The SDK ships without a wallet dependency on purpose.
const signer: X402Signer = {
  async settle(envelope) {
    const txHash = await yourWallet.sendUsdcTransfer({
      to: envelope.recipient,
      amount: envelope.amount,
      chain: envelope.network,
    });
    return {
      reference: txHash,
      network: envelope.network,
      amount: envelope.amount,
      asset: envelope.asset,
    };
  },
};

const alter = new AlterClient({
  endpoint: "https://mcp.truealter.com",
  x402: new X402Client({
    signer,
    networks: ["base", "base-sepolia"], // policy allow-list
    assets: ["USDC"],
    maxPerQuery: "0.10",                 // refuse anything over $0.10 USDC
  }),
});

// Auto-retries with payment when the server returns 402
const vector = await alter.getFullTraitVector({
  candidate_id: "550e8400-e29b-41d4-a716-446655440000",
});

If a quoted envelope exceeds maxPerQuery, uses an unallowed network, or names an unallowed asset, the SDK rejects the call with AlterError before invoking the signer — no on-chain transaction is broadcast.

Provenance Verification

Every response from a medium- or high-blast-radius tool ships with an ES256 JWS in _meta.provenance. The signature covers a canonical JSON serialisation of the response payload, the tool name, the call timestamp, the requesting agent's key hash, and a monotonic sequence number.

const result = await alter.getFullTraitVector({
  candidate_id: "550e8400-e29b-41d4-a716-446655440000",
});

const check = await alter.verifyProvenance(result._meta?.provenance);
if (!check.valid) throw new Error(`ALTER provenance check failed: ${check.reason}`);

The SDK fetches public keys from https://api.truealter.com/.well-known/alter-keys.json and caches them per their Cache-Control headers. The endpoint returns a JWKS containing all current and recently-rotated signing keys; verifying clients should accept any key whose kid matches and is still within its validity window.

verify_at hostname allowlist (v0.1.1+)

Every provenance envelope may carry a verify_at hint telling the SDK where to fetch the JWKS from. Because that hint is server-supplied, a hostile MCP server could otherwise point it at an attacker-controlled JWKS and pass ES256 verification with its own signing key. The SDK therefore gates verify_at through a hostname allowlist (default: api.truealter.com, mcp.truealter.com) and rejects http:// URLs unconditionally. Downstream integrators with their own deployment can extend the allowlist — without forking the SDK — via verifyAtAllowlist on either AlterClient or a direct verifyProvenance() call:

import { AlterClient, DEFAULT_VERIFY_AT_ALLOWLIST } from "@truealter/sdk";

const alter = new AlterClient({
  verifyAtAllowlist: [
    ...DEFAULT_VERIFY_AT_ALLOWLIST,   // keep the ALTER canonicals
    "keys.myorg.example",              // plus your own JWKS host
  ],
});

If you pin jwksUrl explicitly, the envelope's verify_at is ignored entirely — the pinned URL wins. The https: scheme requirement applies to pinned URLs too.

Why this matters

Provenance verification is how Agent A trusts that data from Agent B truly came from ALTER. If Agent B forwards a trait vector or belonging score, Agent A can replay the JWS against ALTER's published keys and confirm — without contacting ALTER again — that the payload is authentic, untampered, and was issued for the person Agent B claims it concerns. No shared secret, no trust in the intermediary, no out-of-band coordination.

This is what makes ALTER usable as identity infrastructure rather than just an API: signed claims propagate across agent networks the same way DKIM-signed mail propagates across SMTP relays.

Discovery

ALTER follows the discovery cascade specified in draft-morrison-mcp-dns-discovery-01. Given a domain (e.g. truealter.com), the SDK resolves the MCP endpoint in three steps, falling through on each failure:

1. DNS TXT — query _mcp.truealter.com for a TXT record of the form mcp=https://mcp.truealter.com;version=2025-11-25. This is the fastest path and works without an HTTP round-trip.
2. .well-known/mcp.json — fetch https://truealter.com/.well-known/mcp.json for the standard MCP server descriptor. This is the cross-vendor fallback.
3. .well-known/alter.json — fetch https://truealter.com/.well-known/alter.json for the ALTER-specific descriptor, including signing keys, x402 wallet address, supported tool tiers, and federation endpoints.

import { discover } from "@truealter/sdk";

// Cascading discovery (DNS TXT → mcp.json → alter.json)
const descriptor = await discover("truealter.com");

// Skip the DNS step (e.g. in browsers or Cloudflare Workers)
const httpsOnly = await discover("truealter.com", { skipDns: true });

The IETF draft is being progressed through the IETF; until adoption, the cascade order may change. Pin the SDK version to a specific minor release if you depend on this behaviour.

Local Daemon vs Remote MCP

The companion Python package alter-identity (PyPI) ships a persistent daemon that holds a hot in-process cache of trait vectors and identity stubs over a Unix socket at unix:///run/user/$UID/alter-identity.sock. Hooking the TypeScript SDK up to that daemon is on the roadmap — for now, every AlterClient talks to the configured remote endpoint over HTTPS.

When the local-daemon adapter ships:

• Latency: sub-millisecond for cached L0 calls.
• Cost: zero on cached responses — x402 settlement is skipped.
• Provenance: the daemon re-signs responses with its locally-bound ES256 key, so downstream verification remains uniform.

Until then, use endpoint: "https://mcp.truealter.com" (the default) and the SDK behaves identically across Node, Deno, Bun, Cloudflare Workers, and the browser.

Tools

Free tools (L0 — no payment required)

Premium tools (L1–L5 — x402 payment required)

License

Apache License 2.0. See LICENSE for the full text.

Copyright 2026 Alter Meridian Pty Ltd (ABN 54 696 662 049).

ALTER, the Trill (~), and the Golden Thread are trademarks of Alter Meridian Pty Ltd.