Undertow MCP | Market liquidity and exit-cost tools

Endpoint: https://api.seiche.info/undertow/mcp (streamable HTTP, no install)

Start with a question: Compare BTC exit estimates in your browser. Choose a dollar size and click to read the current published venue estimates, snapshot date and method. No account, key, wallet or client installation is needed for this example. The result is a depth-based estimate, not an executable quote. The same page provides Codex, Claude Code, Cursor and VS Code setup.

Try it live: liquilens-undertow.com/developers · API catalog: api.seiche.info/undertow

Undertow exposes estimated exit cost by position size and venue, the concentration of quoted depth, realized depth-collapse episodes, and liquidity tiers across market segments. This MCP 1.10.0 endpoint exposes 18 read-only tools, split into 10 public and 8 subscriber tools, plus 3 guided prompts. Its capability inventory is pinned to liquilens-undertow commit 9d1fedc28dca133fe6f9e018af1e381e247b8c9b, the hosted implementation at deploy/hetzner/undertow-mcp. The stdio discovery server in undertow_mm/mcp_server.py is a separate discovery surface; it is neither this registry listing nor the public stdio adapter provided here.

Add it

Claude Code:

claude mcp add --transport http undertow https://api.seiche.info/undertow/mcp

Claude.ai / ChatGPT / Cursor: add a custom connector or MCP server with the URL above. No key and no wallet for the free surface.

This repository contains the discovery manifest, documentation and an optional anonymous stdio adapter for the hosted service. The official registry serves io.github.beepboop2025/undertow version 1.10.0.

Local stdio and container installation

The direct hosted URL above remains the simplest connection. For clients that require stdio, clone this repository at a reviewed commit and use Python 3.12+ and uv:

uv sync --locked
uv run --locked undertow-mcp

A Claude Desktop configuration can use uv as its command and ["run", "--directory", "/absolute/path/to/undertow-mcp", "--locked", "undertow-mcp"] as its arguments. The stdio adapter exposes only the 10 anonymous tools and three prompts; subscriber access uses the direct hosted URL instead.

For Docker and Glama's container build:

docker build -t undertow-mcp .
docker run --rm -i undertow-mcp

The root Dockerfile runs as an unprivileged user and starts stdio directly. No API key, bearer token, wallet, port, volume or environment setting is needed. Outbound HTTPS access to the fixed api.seiche.info endpoint is required. Redirects, environment proxies and arbitrary upstream URLs are disabled. Requests are capped at 64 KiB, responses at 2 MiB, and each upstream operation at 10 seconds including queue wait. No automatic retries or response cache can hide outages or spend a quota twice. Upstream version/catalog drift fails closed. Tool results, native isError values and rights refusals are preserved.

A Glama maintainer can configure the root Dockerfile, complete its build test, and publish a Glama release from the listing's admin page. A GitHub commit or release does not create a Glama release. This repository does not claim a grade until Glama has actually rescanned and inspected it. See Glama's release guide.

Hosted protocol compatibility

• 2026-07-28: stateless requests use server/discover, per-request _meta, MCP-Protocol-Version, and mirrored Mcp-Method / Mcp-Name routing headers.
• 2025-11-25, 2025-06-18, and 2025-03-26: retained legacy initialization, tools, prompts, notifications, batching, and ping behavior.
• Discovery identifies all ten public and eight subscriber tools. Anonymous tools/list returns only the public inventory; entitlement is checked fresh on every subscriber request.
• resources/list and resources/templates/list return explicit empty catalogs. resources/read returns a not-found error and never invents a resource.

Example

In the snapshot generated at 2026-08-08T15:01:22Z, selling $1,000,000 of BTC at the selected $1,000,000 published size rung cost 2.386 bp on Binance and 13.623 bp on Bitfinex: about $238.60 against $1,362.30. Gemini was the dearest observed venue in that same snapshot at 25.852 bp, or about $2,585.20.

Venue rankings can change during the day, and those differences are not visible in a single consolidated price. Undertow publishes the observation time and venue inputs with the estimate.

Tools

Prompts

Commodity futures are intentionally absent from that table. Undertow has no licensed point-in-time depth by contract month, venue and session, so executable commodity exit cost is CANNOT_ASSESS_EXECUTABLE_EXIT_COST; open interest or daily volume is never substituted. For aggregate WTI/Henry Hub cash pressure, Cushing and benchmark structure, call Seiche's public oil_funding_context or use /oil in @seiche_desk_bot.

Limitations

• PARTIAL is not calm. A segment reads PARTIAL when fewer than two of its measures have earned a scoring history. Four of nine segments read PARTIAL on 2026-07-30, and the board says so instead of guessing.
• Exit costs are estimates, interpolated from published quote depth at the 1% and 2% bands. Never a book walk. The snapshot refreshes roughly hourly, so it is a snapshot and not a real-time feed.
• Crypto measures are still accruing, so the board has not earned a crypto stress percentile and you should never quote one from it.
• The sealed record includes misses. Calls are hash-chained and signed before their outcomes are knowable, then scored against the point-in-time board.
• Commodity execution is a declared coverage gap. Ballast is useful upstream context from Seiche, not a depth ladder and not an Undertow exit-cost estimate.

Research and market data, not investment advice.

Subscriber tier

The Agent and Desk tiers unlock the eight subscriber tools. Send /agent to the Telegram bot to mint a bearer token:

{
  "mcpServers": {
    "undertow": {
      "url": "https://api.seiche.info/undertow/mcp",
      "headers": { "Authorization": "Bearer YOUR_TOKEN" }
    }
  }
}

The token proves identity only. Entitlement is re-read from live membership on every call, so access stops when the subscription does rather than when the token expires. Subscriber tools are invisible to an anonymous tools/list, and agent_access_status tells you where you stand.