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.
npx skills add SpartanLabsXyz/simmer-sdk --skill simmer-x402git clone --depth 1 https://github.com/SpartanLabsXyz/simmer-sdkWrote 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.
[](https://agentmods.dev/skills/spartanlabsxyz/simmer-sdk/simmer-x402)<a href="https://agentmods.dev/skills/spartanlabsxyz/simmer-sdk/simmer-x402"><img src="https://agentmods.dev/badge/skills/spartanlabsxyz/simmer-sdk/simmer-x402/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.
<a href="https://agentmods.dev/skills/spartanlabsxyz/simmer-sdk/simmer-x402"><img src="https://agentmods.dev/badge/skills/spartanlabsxyz/simmer-sdk/simmer-x402.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector warn
SkillSpector: 5 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 77 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 82 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 87 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 173 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 92 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.
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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00063 | $0.02178 |
| Opus 5 | $0.00032 | $0.01089 |
| Sonnet 5 | $0.00013 | $0.00436 |
| Haiku 4.5 | $0.00006 | $0.00218 |
Grade A, and why
simmer-x402 scanned grade A with 0 findings 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 12d 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.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 203 lines — stays where its author put it; the contents beside it link to each section on GitHub.
x402 Payments
Pay for x402-gated APIs using USDC on Base. This skill enables agents to autonomously make crypto payments when accessing paid web resources.
🚨 Framework for x402 payment plumbing, not financial advice. Read DISCLAIMER.md before connecting to a wallet with real funds. Cap per-call payments with
--max <USD>or theX402_MAX_PAYMENT_USDenv var; the wallet should be a scoped working-capital wallet, not your treasury.
This is a template. The default
x402_cli.pyhandles 402 detection, payment-payload construction, and balance checks. Bring your own policy for which endpoints to pay for, what max payment per call is acceptable, and how to scope the funded wallet.
When to Use This Skill
Use this skill when:
- A skill or agent needs to fetch data from an x402-gated API (e.g., Kaito mindshare)
- You encounter HTTP 402 Payment Required responses
- You need to check your Base wallet balance (USDC + ETH)
- You want to pay for Simmer premium endpoints beyond free tier rate limits
Setup
-
Install the Simmer SDK
pip install simmer-sdk -
Set your wallet private key
export EVM_PRIVATE_KEY=0x...your_private_key...Falls back to
WALLET_PRIVATE_KEYifEVM_PRIVATE_KEYis not set (same key Simmer/Polymarket users already have). Your EVM address works on all chains — Polygon for trading, Base for x402 payments. -
Fund with USDC on Base
- Send USDC to your wallet address on Base network
- x402 payments on Base are fully gasless — you only need USDC, no ETH
-
Install dependencies
pip install x402[httpx,evm]
Quick Commands
| Command | Description |
|---|---|
python x402_cli.py balance |
Check USDC and ETH balances on Base |
python x402_cli.py fetch <url> |
Fetch URL with automatic x402 payment |
python x402_cli.py fetch <url> --json |
Same but output raw JSON only |
python x402_cli.py fetch <url> --dry-run |
Show payment info without paying |
python x402_cli.py fetch <url> --max 5.00 |
Override max payment limit |
python x402_cli.py rpc <network> <method> [params...] |
Make RPC call via Quicknode x402 |
What ships with it
5 files 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.
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.
- 12d ago First seen · 203 lines · 63 tokens per session scan A a7b2c9da3ee9
simmer-x402 is a skill published in the GitHub repository SpartanLabsXyz/simmer-sdk (48 stars, last pushed today), licensed MIT. It adds 63 tokens to every session and 2,178 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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