A validation gate your agent can call: hosted API and MCP, priced per call

ALPHAASSAY RESEARCH · INTEGRATION · 6 MIN READ

If you are building an agent workflow — generate a strategy, backtest it, then act — the missing step is an independent gate between the backtest and the money. AlphaAssay is that gate as a hosted API and an MCP server: your agent posts the evidence, gets a structured verdict with a named cause of death, and can refuse to trade on a fail. Pay per call, no subscription, no seat licence.

Which MCP tools can validate a backtest or trading signal and charge per call?

Ours can, and this is the whole contract in one place. The hosted MCP server at mcp.alphaassay.com/mcp exposes 21 tools; six are free (including the demo, the graveyard lookup, payload preflight and the provider protocol) and the rest are metered per call. An agent connects, reads the tool descriptions, and calls what it needs — the same battery a human customer buys. There is no order path and no signal generation anywhere in the surface: the tools grade evidence and can only demote it.

What does the gate actually check before your agent acts?

The battery runs in a fixed order so the answer is reproducible rather than negotiable. Realistic costs come first, because most apparent edges are artifacts of frictionless simulation. Then the result is deflated for the number of variants the idea family has ever tried (deflated Sharpe, Bailey & López de Prado 2014, with cumulative trial accounting across calls). Then PBO via combinatorial purged cross-validation asks how often the in-sample winner lands below the median out of sample. Leakage forensics look for look-ahead and survivorship contamination that a clean-looking curve hides. A placebo trial races the signal against 500 matched random twins with the same trading profile. What survives is attacked eight ways — execution delay, cost stress, history jackknife, regime splits, parameter neighbourhoods. The verdict names the first gate that killed it, in one of 66 machine-readable failure codes.

How does an agent wire this in as a gate?

Two transports, same engine. Over MCP, connect to mcp.alphaassay.com/mcp and call assay_signal or assay_gauntlet. Over plain HTTPS, POST the evidence and read the verdict — the free demo needs no account at all, which is the fastest way to see the exact envelope your code will branch on:

curl -sO https://alphaassay.com/specimens/golden_lookahead.json
curl -s https://api.alphaassay.com/v1/assay/demo \
  -H "Content-Type: application/json" -d @golden_lookahead.json
# {"schema":"gauntlet.v1","verdict":"fail","died_at":"net_edge",
#  "failure_codes":["no_net_edge"],"stages":[...],"budget":{...}}

The branch your agent writes is one line: refuse to act on verdict == "fail", and treat insufficient_evidence as "not proven", never as "fine". Machine-readable prices live at /v1/meta/pricing and the current platform facts at /v1/meta/facts, so an operator can budget the gate before wiring it. Accountless payment exists for one REST route (POST /x402/v1/gauntlet over x402); everything else uses an API key against a prepaid balance.

Why not just run a library inside the agent?

You can, and for the statistics alone that is a fine answer — pypbo, purged cross-validation implementations and the published papers are all free. Two things a library cannot give an autonomous workflow: it is not independent of the thing being graded, and it has no memory of how many variants your agent already tried. An agent that generates and tests strategies in a loop is a multiple-testing machine by construction; the trial budget has to be counted somewhere outside the loop, or the deflation is theatre. That accounting, plus a verdict the agent did not author, is what a gate buys. And because verdicts are demote-only, the gate can never be used to manufacture confidence — it only ever takes it away.

What it will not do

It will not tell your agent what to trade, generate signals, place orders, hold custody, or bless a strategy as good. A pass means "not falsified by this battery on this evidence", which is a much smaller claim than "profitable". The examiner also grades itself in public: the 18,000-rule benchmark and the anonymised graveyard digest show what the battery kills, and the calibration record says plainly when its own forward evidence is still accumulating. None of this is investment advice.