KalshiPolymarket US Paper / demo first
PASS WITH FIXES Tested on Composer 2.5, , result: PASS WITH FIXES. We built the limits, kill switch and daily-loss stop from the prompt as a standalone kit (2 tests passing). Kalshi and Polymarket US cancel-all were mocked: no real keys, orders or money. The prompt below includes the fixes from that run.
Short answer: A good kill switch for a prediction-market bot has three layers: a local KILL file the bot checks before every order, the venue's cancel-all endpoint (Kalshi DELETE /portfolio/events/orders, Polymarket US POST /v1/orders/open/cancel), and Kalshi order groups as a server-side safety net. Position limits belong in code and are checked before every order.
KILL file (or BOT_KILL=1) before every order and refuses to trade if it's there.DELETE /portfolio/events/orders (cancels resting orders across shards; Kalshi notes newly placed orders may also be cancelled during the minute after the request). Polymarket US POST /v1/orders/open/cancel.Retrofit any existing bot with hard limits checked in code, a one-file kill switch, a cancel-all command for each venue, and Kalshi's server-side order-group safety net, then prove they work in demo/paper.
Anyone with a bot (theirs or from GitHub) that doesn't yet have a fast, tested way to stop.
Works in Claude Code, Cursor, Codex/ChatGPT, Grok or any agent that can write files. Paste it into an empty folder. Read what it builds before you run anything.
Add hard risk limits and a three-layer kill switch to this existing trading
bot. Read the codebase first and list every place an order can be created.
(If there is no bot in this folder yet, stop and tell me. Don't invent one.)
Use only endpoints documented at https://docs.kalshi.com and
https://docs.polymarket.us. Ask me if unsure.
1) limits.json + risk.py
- max_contracts_per_order, max_open_exposure_usd, max_daily_loss_usd,
max_orders_per_minute, allowed_tickers (allowlist).
- check_order(order, state) raises RiskError on any breach. EVERY code
path that creates an order must call it first. Add a test that fails if
any order function is reachable without check_order.
2) Local kill switch
- If a file named KILL exists in the project root, or BOT_KILL=1, refuse
all new orders and log "KILL ACTIVE" each loop. Checked inside
check_order AND at the top of the main loop.
3) Venue cancel-all (cancel_all.py)
- Kalshi: DELETE /portfolio/events/orders (signed request).
- Polymarket US: POST https://api.polymarket.us/v1/orders/open/cancel
(signed request).
- Print what was cancelled; then re-query open orders to confirm.
- If keys are missing (or BROKER_MOCK=1), print the exact request it
would send and send nothing.
4) Kalshi server-side safety net (if the bot trades Kalshi)
- On startup, POST /portfolio/order_groups/create with contracts_limit
from limits.json (order_group_contracts_limit), store the id, and pass
order_group_id on every order.
- On shutdown, leave the group (don't delete it automatically) and log
its id so I can inspect it.
5) Daily loss stop: track daily loss as a non-negative dollar amount
(max(0, -realized PnL today)). When it reaches max_daily_loss_usd,
create the KILL file automatically and run cancel-all.
6) Tests for every limit, the KILL file, and the daily loss stop. Run them.
Don't change the strategy logic. Show me a diff summary when done.BROKER_MOCK=1 python cancel_all.py shows the requests without sending them): start the bot, touch KILL, confirm no new orders, run python cancel_all.py, then confirm in the venue UI that nothing is resting.order_group_contracts_limit very low, let a couple of tiny demo fills happen, and confirm Kalshi triggered the group and cancelled the rest.touch KILL → python cancel_all.py → check the venue UI → revoke the API key if anything looks wrong.Test every layer before any live use:
https://external-api.demo.kalshi.co/trade-api/v2) with demo keys. Order groups and cancel-all behave like production there.Time yourself. You want "something's wrong" → "everything cancelled" in under 30 seconds.
Tick every box before the bot touches real money. The full rules file, .gitignore and pre-commit hook are in the Safety Pack.
.env and *.pem are in .gitignore, and your AI tool is blocked from reading them (see the Safety Pack).touch KILL) stops new orders immediately, and a second command cancels every resting order through the venue's cancel-all endpoint.--live flag and a typed confirmation, and you only flip it after days of clean paper logs.Endpoints and rules were checked against these pages on Oct 19, 2026. APIs change, so if something here disagrees with the official docs, trust the docs and tell us.
A fast, reliable way to stop a bot from placing new orders and cancel the ones already resting. Good setups have a local switch (a file or flag the bot checks before every order), a cancel-all command using the venue's API, and if available, a server-side limit like Kalshi order groups.
A Kalshi feature that tracks fills for a group of orders in a rolling 15-second window. If fills exceed the group's contracts limit, Kalshi cancels all resting orders in the group and rejects new ones until you reset it.
Send a signed DELETE /portfolio/events/orders request. It cancels resting event-market orders across exchange shards, and Kalshi notes orders placed in the following minute may also be cancelled.
Send a signed POST https://api.polymarket.us/v1/orders/open/cancel, which cancels all your open orders, optionally filtered by market. Pure cancels aren't affected by the 5-second latency stopgap that can reject new orders.
One new build recipe, one safety tip, and API changes worth knowing about. Free. No picks, ever.
A copy-paste AI prompt and step-by-step guide to the Polymarket US API: public market data with no key, then authenticated reads. Includes the international Gamma API, read-only, with a geoblock check.
Step-by-step: use Claude Code to build a Polymarket US trading bot that runs in paper mode by default, with a local paper ledger, order preview, hard position limits and a kill switch.
Get started with the Kalshi API using an AI coding tool: public market data with no key, then RSA-PSS or Ed25519 signed requests against the Kalshi demo environment. Endpoints checked against the official docs.