Undertow MCP | Market liquidity and exit-cost tools
Endpoint: https://api.seiche.info/undertow/mcp (streamable HTTP, no install)
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 1.9.0 endpoint exposes 17 read-only tools, split into 9 public and 8 subscriber
tools, plus 3 guided prompts. Its capability inventory is pinned to signed core commit
79b3f6bc40b2917795954ad5a7119a8a95ce5b74.
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 is the discovery and documentation mirror. The official registry serves
io.github.beepboop2025/undertow version 1.9.0.
Protocol compatibility
2026-07-28: stateless requests useserver/discover, per-request_meta,MCP-Protocol-Version, and mirroredMcp-Method/Mcp-Namerouting headers.2025-11-25,2025-06-18, and2025-03-26: retained legacy initialization, tools, prompts, notifications, batching, and ping behavior.- Discovery identifies all nine public and eight subscriber tools. Anonymous
tools/listreturns only the public inventory; entitlement is checked fresh on every subscriber request. resources/listandresources/templates/listreturn explicit empty catalogs.resources/readreturns 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
| Tool | What it serves | Surface |
|---|---|---|
agent_access_status | Your current tier, daily meter, grants, and the exact route to Agent or Desk access | free |
board_full | Every measure with its stress percentile or ACCRUING label, limits and analyst note | subscriber |
corporate_transmission | Whether funding stress is reaching nonfinancial firms | subscriber |
depth_episodes | Realized depth-collapse episodes with onset, trough, drawdown and recovery, against thresholds declared before any episode accrued | free |
divergence_status | Compact comparison of corporate and household transmission regimes | subscriber |
exit_cost | Per-venue sell cost in basis points at the nearest published size rung, cheapest and dearest venue with approximate dollar cost, and the venue spread | free |
exit_desk_full | BTC and ETH at every published rung, plus the venue-failure withdrawal scenario | subscriber |
exit_schedule | Position-sized hour-by-hour liquidation schedule beside immediate and TWAP baselines | subscriber |
household_credit | Whether funding stress is reaching household balance sheets | subscriber |
latest_article | The exact reviewed daily market-liquidity editorial with its evidence clock and publication authority | free |
liquidity_tiers | A liquidity tier per market segment (UST, IG, HY, equities, ETF, FX, China basin, crypto) with the funding-stress overlay | free |
sealed_record | The sealed forward-calls record, hash-chained and signed before outcomes, misses kept | free |
tide_clock | Clock-phase liquidity map and exit-cost-by-phase for BTC or ETH perpetuals | subscriber |
unwind_stress | Full institutional unwind and forced-sale stress pack | subscriber |
unwind_watch | Banded public watch over institutional unwind time and forced-sale pressure, with exact sensitive quantities withheld | free |
venue_concentration | The BTC depth backbone: top venue share of aggregate depth, HHI, effective venue count, per-venue depth in USD | free |
venue_price_reconciliation | A consensus mark weighted by resting depth over squared half-spread, plus the gap between the deepest venue and consensus | free |
Prompts
| Prompt | Guided playbook |
|---|---|
can_this_book_exit | Compare watched-book door width, unwind horizon, margin clock, venue concentration, and realized depth collapses |
exit_cost_check | Price a position-sized exit across venues and identify the observed depth limitations |
market_liquidity_briefing | Read the market-level liquidity board, funding overlay, concentration, and current exit-cost evidence together |
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.
Only tools/call is metered, reported on X-MCP-Usage-Used, X-MCP-Usage-Limit
and X-MCP-Usage-Remaining. GET /undertow/mcp/usage is the self-meter. Hitting a
quota returns a normal JSON-RPC result carrying isError and an upgrade pointer,
never a dropped connection.
About this repository
This repo is the listing: a README and the two manifests that let directories describe the server accurately. The server itself is hosted at the endpoint above; its source and verification tests live in the Undertow product repository. Nothing in this listing repo computes a number.
Siblings from the same lab
- Seiche: US dollar funding stress.
- LiquiLens: bank, NBFC and lender failure risk, and whether that stress is reaching firms and households.
- groundcheck: claim grounding and citation verification for general text.
- Palimpsest: live internet-censorship signals.
Human front door: liquilens-undertow.com and the Telegram desk.