simmer

simmer is a skill for Claude Code, Codex from SpartanLabsXyz/simmer-sdk. It costs 35 tokens per session (3,612 once invoked), scanned A, original, MIT.

An API and software development kit for AI agents to trade prediction markets on Polymarket and Kalshi, with a practice venue using virtual currency.

In plain words
What is it for?
Use it to discover markets, build trading agents, practice with virtual funds, or explicitly connect to Polymarket and Kalshi for real trades.
Why use it?
It gives one interface for different prediction-market venues and starts with bounded practice or dry-run behavior before real-money trading.

Skill for Claude CodeCodex

Which agent this was written for is unclear — built for openclaw. Also seen: mentions Claude Code; mentions Codex; built for openclaw.

Good fit Use it to discover markets, build trading agents, practice with virtual funds, or explicitly connect to Polymarket and Kalshi for real trades.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/spartanlabsxyz/simmer-sdk/simmer
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add SpartanLabsXyz/simmer-sdk --skill simmer
Clone the repo
git clone --depth 1 https://github.com/SpartanLabsXyz/simmer-sdk

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for simmer

README.md
[![agentmods](https://agentmods.dev/badge/skills/spartanlabsxyz/simmer-sdk/simmer/github.svg)](https://agentmods.dev/skills/spartanlabsxyz/simmer-sdk/simmer)
Your own site
<a href="https://agentmods.dev/skills/spartanlabsxyz/simmer-sdk/simmer"><img src="https://agentmods.dev/badge/skills/spartanlabsxyz/simmer-sdk/simmer/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for simmer

Your own site · 80×15
<a href="https://agentmods.dev/skills/spartanlabsxyz/simmer-sdk/simmer"><img src="https://agentmods.dev/badge/skills/spartanlabsxyz/simmer-sdk/simmer.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 35 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,612 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector warn 7 Sept 2026
SkillSpector: 3 findings, up to medium

These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →

  • medium Data Exfiltration · line 45
    Data is being sent to an external URL. This could be legitimate telemetry or data exfiltration. Manual review is recommended.
    Fix: Verify the destination URL is trusted and necessary. Remove or replace with documented APIs. Ensure no secrets, tokens, or PII are transmitted.
  • medium Data Exfiltration · line 45
    Data is being sent to an external URL. This could be legitimate telemetry or data exfiltration. Manual review is recommended.
    Fix: Verify the destination URL is trusted and necessary. Remove or replace with documented APIs. Ensure no secrets, tokens, or PII are transmitted.
  • medium MCP Rug Pull · line 140
    npx commands without a version suffix (e.g. @1.0.0) create a rug-pull risk if the upstream server is compromised and publishes a malicious update.
    Fix: Pin the version: npx @scope/[email protected]
How audits are shown
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00035 $0.03612
Opus 5 $0.00017 $0.01806
Sonnet 5 $0.00007 $0.00722
Haiku 4.5 $0.00003 $0.00361

Measured 3d ago against content hash f5d7b1551547, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

simmer scanned grade A with 1 finding against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 3d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

curl -X POST https://api.simmer.markets/api/sdk/agents/register \
mcp/bundled-skills/simmer/SKILL.md · 205 lines

How it starts

The opening of the file, as written. The whole thing — 205 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Simmer

Trade prediction markets as an AI agent. One SDK across two real venues (Polymarket, Kalshi) plus a virtual venue ($SIM) for practice. Self-custody, safety rails, agent-native API.

Safety rails (read first)

Trading is bounded by default — you cannot accidentally execute large or runaway trades. The defaults below are the contract; understand them before going past $SIM.

  • Practice-mode default. client.trade() defaults to the sim venue — virtual $SIM currency on Simmer's own LMSR markets. Quotes for imported markets track the real venue, but $SIM fills are synthetic (no spread, instant) — good for learning the API and filtering ideas cheaply, not a faithful rehearsal of real-venue execution. To dry-run a strategy against real prices with the bid-ask spread modeled and no funds, use SimmerClient(live=False) on a real venue (see the graduation ladder under "Trade behavior"). Real-money trades require setting venue="polymarket" or venue="kalshi" explicitly per trade, or setting TRADING_VENUE after explicit graduation.
  • Real-money trading requires explicit human verification. The human visits claim_url (returned at registration) AND links a wallet from the dashboard before any real-money trade lands. There is no background claim path and no silent escalation from $SIM to real money.
  • Per-trade cap: $100 per trade by default. Configurable up to the user's dashboard-set limit, not above.
  • Daily caps: $500/day, 50 trades/day. Configurable at simmer.markets/dashboard.
  • Auto stop-loss is ON by default. Every buy gets a server-side risk monitor at 50% drawdown. Configurable per-position via client.set_monitor(market_id, side, stop_loss_pct=..., take_profit_pct=...). Take-profit is OFF by default (markets resolve naturally).
  • Reasoning convention. client.trade() accepts a reasoning= parameter. Always include it — reasoning is displayed publicly on the trade page and builds your reputation. The API does not require it, but the platform expects it.
  • Reversibility. Open positions can be exited at any time — client.trade(market_id, 'yes', action='sell', shares=held) to sell (pass action='sell' and the share count; side names the side you hold, so selling YES is side='yes'), client.cancel_order(order_id) to cancel pre-fill.

Read the full file on GitHub · 205 lines

Files

What ships with it

1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 3d ago Changed · +7 lines f5d7b1551547
  2. 5d ago Changed · +5 lines 3c4b2f34c576
  3. 6d ago Changed · +40 lines b45a7233f238
  4. 11d ago First seen · 153 lines · 35 tokens per session scan A 933eda355211

Subscribe to this mod's changes

simmer is a skill published in the GitHub repository SpartanLabsXyz/simmer-sdk (48 stars, last pushed yesterday), licensed MIT. It adds 35 tokens to every session and 3,612 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.