TuringCorp — MCP server

A decision model for the calls that don't have a right answer. Your agent has two defensible options and has to pick one. Send both: a panel of models judges them together and returns the better one, how far apart it judged them (a calibrated confidence), and why.

• Endpoint (canonical): https://mcp.turingcorp.net/mcp
• Aliases: https://mcp.turingcorp.net/ and https://mcp.turingcorp.net/mcp/
• Health: https://mcp.turingcorp.net/healthz
• Transport: Streamable HTTP, stateless (no session, no Durable Object). GET /mcp → 405 is normal.
• Protocol: MCP 2026-07-28 (modern) and 2025-06-18 (legacy) — one route serves both.
• Discovery methods (server/discover, tools/list) need no credentials — directory scanners can read the full tool list unauthenticated, by design.

The one tool: decide

A successful call returns the decision inline. job_id, betterOption, confidence and reason all arrive in the same tool result — there is nothing to poll and nothing to fetch afterwards. The job_id is only for the case where the call never came back (timeout, dropped connection, client gave up waiting).

confidence is this service's own judgement of how far apart the two options were — a reference for your decision-making, not an instruction, not a result, and not a prediction of how the choice turns out. As a rough reading: ≥90% clearly apart · 80–90% apart, less clearly · 70–80% a closer call · <70% close to evenly matched. These ranges are descriptive only. Choose your own threshold for your own use case; for high-stakes or irreversible decisions apply your own review policy. Observed accuracy for each range, and how it was measured, is published at https://api.turingcorp.net — that page is the authority on the bands and their measured accuracy.

⚠️ idempotentHint: false is an honest declaration: a retried call is a new call. Record the job_id the result returns — a decision you have already paid for can be collected for 7 days with the same credential (GET https://api.turingcorp.net/v1/jobs?job_id=<id>; without the id, GET https://api.turingcorp.net/v1/jobs lists the job ids for that credential). Retrieve instead of retrying.

When not to use it

• More than two options. It compares exactly A and B — there is no third slot, and it will not rank a list.
• Anything you can compute or verify. A spec, a test, a price, a document: if something objective decides it, use that. This is for choices where no objective rule does.
• Factual questions. It picks between two candidates; it does not look anything up.
• Speed-critical paths. A decision is a long call and a paid one. Do not put it behind a request that has to answer in seconds.
• High-stakes irreversible calls without review. Route on the confidence and keep your own review policy.

How to fill the three arguments

• task — state the decision neutrally, without leaning toward either side: "Which email do I send?", not "Should I send the honest one?"
• optionA / optionB — one concrete option each, plus the case for it. Plain text or Markdown, any length; keep the two sides roughly comparable so the comparison is fair.
• One option = one plan. Do not bundle alternatives into a single side ("go indoors or postpone"): it compares the two slots, it does not split one of them for you.

{
  "task": "Which version of the delivery-slip email do I send to a client we want to keep?",
  "optionA": "Short and direct: the integration took longer than planned, delivery moves to the 24th, everything else is unchanged.",
  "optionB": "Warmer and longer: thank them for the kickoff, explain that dependencies took more time, offer to walk through the details."
}

More patterns — choosing the version you send, thresholding on the confidence, and writing the two options so the comparison is fair: docs/COOKBOOK.md.

Retrieving a result

Every call returns a job_id. If the call times out or the connection drops, do not call again — retrieve it:

• With the id — GET https://api.turingcorp.net/v1/jobs?job_id=<id> with the same Agent Pass. A client that speaks the io.modelcontextprotocol/tasks extension can use tasks/get with {"taskId":"<id>"} on the MCP endpoint instead.
• Without it — GET https://api.turingcorp.net/v1/jobs lists the job ids that credential created in the last 7 days; then fetch one as above. The list carries only the job id, the product and a timestamp — fetch a job by id to see what it was.
• Nothing yet — an empty list is not an error, and there is no job_id=0 placeholder: {"object":"list","window_seconds":604800,"data":[]}. Asking for 0 returns 404 No such job.

Retrieval returns the job's status and, once it succeeded, the same body the call itself would have returned. A job that is not yours, or older than 7 days, is reported as unavailable. GET https://api.turingcorp.net/v1/account returns {"account_id":"…"}.

See it decide first

There is no free tier, so we publish the evidence instead: 27 real decisions, recorded verbatim — the question, both options, which one was preferred, the confidence reported, and the reason. Nine domains, three cases each: Writing · Tech · Business · Research · Career · Money · People · Travel · Everyday.

→ https://github.com/TuringCorp-net/poe-demo-public — dataset: examples.json

Read the confidence column first. On ordinary, closely matched questions it reports 70–90%, not 99% — and that is the point of a calibrated number rather than a decorative one: a high value means the comparison was decisive and the pick can be acted on, a low value means the two options really are close and the choice stays yours. In this set the range is 27.3%–88.3%, median 74.0%, none above 90%, because these are everyday close calls, not easy ones. What the bands deliver when they are decisive is published at https://api.turingcorp.net.

Authentication

Send an Agent Pass: Authorization: Bearer <pass>.

Issued at https://agent-pass.turingcorp.net — self-service signup (email verification) → top up → get a pass. A pass is valid for 7 days and can be re-rolled. If a call is refused as an invalid credential, sign in there again and re-roll.

Errors fall into two classes, and they arrive in different places:

Credential problems are rejected before the call (HTTP 401 + WWW-Authenticate). Business failures come back as a tool result with isError: true plus a JSON block {error, http_status, action_url, message} — http_status is the upstream status; the tool call itself is HTTP 200.

Branch on the HTTP status first: a 401 will not succeed on retry without a new credential, whereas a business failure was a call that ran and was declined — read the block for the reason and the next step. The detailed contract is under Errors are machine-readable below.

Entry rate limit: 120 requests / 60 s / client IP. This is flood damping, not a quota — the real per-key quota is enforced separately. The counter is approximate: it is maintained per edge location and is eventually consistent, so a brief overshoot is possible.

Two ways in — and they are not the same

• Through an MCP client or host (Claude Code, Cursor, VS Code, Codex, TRAE, Coze…). The host holds the credential and attaches it for you: you do not set an Authorization header yourself, and in most hosts you cannot. The timeout is a host setting, not something you pass in the call.
• Directly against the REST API (https://api.turingcorp.net). Here you do send Authorization: Bearer <Agent Pass> yourself, and you can retrieve a job by id.

⚠️ The part that catches people out: being able to call the tool through a host does not mean you can reach the REST API. The host may never hand you the underlying Agent Pass, so a job-retrieval call you make on your own can come back 401. If your host declares the Tasks extension, retrieve through the tool surface instead (see Retrieving a result); if it does not, retrieval may simply not be reachable from where you are.

Quickstart

You need an Agent Pass to call the tool. Discovery (tools/list) works without one — calling decide does not.

🔑 Where the pass lives matters. If your client can keep it out of the file, do that — VS Code's ${input:…}, Codex's bearer_token_env_var. A pass written in plain text inside mcp.json or any client config is readable by every agent and process that can read that file, and assistants do read their own config — one can print your pass straight into its output. Treat a client config as public within your machine.

1. Get an Agent Pass

Self-service at https://agent-pass.turingcorp.net: sign up with an email address, verify it, add credit. The pass is shown once; it is valid for 7 days and can be re-rolled at any time. Agents can do the same thing over the API — see that site's /llms.txt.

2. Point your client at the endpoint

Any client that reads a JSON config — Cursor, Cline, Windsurf, Claude Desktop:

{
  "mcpServers": {
    "TuringCorp": {
      "type": "http",
      "url": "https://mcp.turingcorp.net/mcp",
      "headers": { "Authorization": "Bearer <your Agent Pass>" }
    }
  }
}

Keep the "type": "http" line: a client that reads a url entry with no type treats it as a local stdio server and skips it.

A client that only speaks stdio needs a bridge, and the credential must go in through --header — mcp-remote does not read an AUTHORIZATION environment variable, so a config that only sets one connects, lists tools, and then fails on the first call with 401. The missing space after Authorization: is deliberate: some clients mangle spaces inside args.

{
  "mcpServers": {
    "TuringCorp": {
      "command": "npx",
      "args": ["-y", "mcp-remote", "https://mcp.turingcorp.net/mcp",
               "--header", "Authorization:${AGENT_PASS}"],
      "env": { "AGENT_PASS": "Bearer <your Agent Pass>" }
    }
  }
}

⚠️ A bare npx -y mcp-remote@latest https://mcp.turingcorp.net/mcp with no credential will connect and list tools, then fail on the first call with 401. That is expected — discovery is open, execution is not.

Claude Code:

claude mcp add --transport http TuringCorp https://mcp.turingcorp.net/mcp \
  --header "Authorization: Bearer <your Agent Pass>"

3. Sanity-check it yourself

Discovery — no credentials needed:

curl -s -X POST https://mcp.turingcorp.net/mcp \
  -H 'content-type: application/json' \
  -H 'accept: application/json, text/event-stream' \
  -H 'mcp-protocol-version: 2026-07-28' \
  -H 'mcp-method: tools/list' \
  --data '{"jsonrpc":"2.0","id":1,"method":"tools/list","params":{"_meta":{"io.modelcontextprotocol/protocolVersion":"2026-07-28","io.modelcontextprotocol/clientCapabilities":{}}}}'

Calling the tool additionally needs mcp-name: decide and the credential:

curl -s -X POST https://mcp.turingcorp.net/mcp \
  -H 'content-type: application/json' \
  -H 'accept: application/json, text/event-stream' \
  -H 'mcp-protocol-version: 2026-07-28' \
  -H 'mcp-method: tools/call' \
  -H 'mcp-name: decide' \
  -H "authorization: Bearer $AGENT_PASS" \
  --data '{"jsonrpc":"2.0","id":2,"method":"tools/call","params":{"name":"decide","arguments":{"task":"Pick a launch date","optionA":"Ship now","optionB":"Wait two weeks"},"_meta":{"io.modelcontextprotocol/protocolVersion":"2026-07-28","io.modelcontextprotocol/clientCapabilities":{}}}}'

Versions

Two version numbers exist and they are not meant to match:

A listing-only change (for example a corrected link) advances the registry version without touching the runtime, so the two can legitimately differ.

Protocol details worth knowing

• Accept must contain both application/json and text/event-stream, or you get 406.
• Protocol versions: one route serves both generations.
  • Modern 2026-07-28 — no initialize handshake; use server/discover and _meta.
  • Legacy — standard initialize handshake. Measured negotiation: a client asking for 2025-11-25, 2025-06-18, or 2025-03-26 is answered with exactly the version it asked for; a modern 2026-07-28 initialize (which is not part of that generation) is answered with 2025-11-25.
  • Server capability discovery via tools/list and server/discover needs no credentials.
• Errors are machine-readable. There are two distinct kinds, and they arrive differently — so branch on the right thing:

In short: credential problems are rejected before the tool runs, so they never appear as a tool result; everything else that fails after that does, with a machine-readable block attached.

• Authorization discovery: 401 responses carry a resource_metadata pointing at /.well-known/oauth-protected-resource. Note that this server uses a static bearer credential, not OAuth — that document says so explicitly rather than sending you into an OAuth flow that does not exist.

Not for browser clients

This endpoint deliberately does not serve browser-based (cross-origin) MCP clients: requests carrying a browser Origin header other than localhost are rejected with 403, and no CORS headers are returned. Browser tooling such as the MCP Inspector works by proxying through a local process, which sends no Origin — that path works normally. If you need a browser page to reach this server, run a proxy you control rather than calling it cross-origin.

What this is not

• One tool only. decide is the entire surface. There is no way to reach other tiers through this endpoint.
• No SLA. No availability commitment is offered, and none should be inferred.
• Not an autopilot. Decider is a component you call. How you gate on it — thresholds, human review, retries — is your policy and stays yours.
• No idempotency key — record the job id instead. A retried call is a new call; collect the result with the job_id instead.

Use it from a coding agent: the Agent Skill

There is an Agent Skill for coding agents (Claude Code, Codex, and anything that reads the same skill convention). It teaches an agent when a two-option judgement is the right tool, how to write the two options so the comparison is fair, and how to read the confidence without over-reading it.

Install it by pointing your agent at this repository, or copy skills/decider/ into your skills directory and add the MCP server to your client (see Quickstart).

About this repository

This repository carries the discovery metadata for the server above — what directory services and clients read to find and describe it.

• server.json — the official MCP Registry manifest
• docs/DIRECTORIES.md — where this server is listed, and what each directory requires
• docs/COOKBOOK.md — worked patterns for handing decide the right kind of call
• skills/decider/ — the Agent Skill

This server is also listed on Smithery: https://smithery.ai/servers/turingcorp/mcp

The server itself is a hosted remote endpoint; nothing here needs to be installed or run.

License

See LICENSE.