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 jxoesneon/Ciel --skill agent-payment-x402git clone --depth 1 https://github.com/jxoesneon/CielWrote 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/jxoesneon/ciel/agent-payment-x402)<a href="https://agentmods.dev/skills/jxoesneon/ciel/agent-payment-x402"><img src="https://agentmods.dev/badge/skills/jxoesneon/ciel/agent-payment-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/jxoesneon/ciel/agent-payment-x402"><img src="https://agentmods.dev/badge/skills/jxoesneon/ciel/agent-payment-x402.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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 | $0.00028 | $0.00464 |
| Opus 5.5 | $0.00011 | $0.00186 |
| Sonnet 5.5 | $0.00006 | $0.00093 |
| Haiku 4.5 | $0.00003 | $0.00046 |
Grade A, and why
agent-payment-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 1mo 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.
What it actually says
CIEL ADAPTATION: Agent Payment Execution (x402)
This skill enables CIEL sub-agents to execute autonomous payments via the x402 HTTP payment protocol. It prioritizes safety through mandatory spending policies and non-custodial wallet management.
Core Mandates
1. Policy-First Delegation
The Orchestrator MUST set a SpendingPolicy before delegating any payment authority to a sub-agent. Sub-agents are prohibited from setting or escalating their own spending limits.
- Per-Task Budget: Maximum spend for a single atomic action.
- Per-Session Budget: Cumulative limit for the entire epic.
- Allowlist: Restricted set of verified recipients or service endpoints.
2. Non-Custodial Security
CIEL agents use non-custodial smart accounts (e.g., ERC-4337). Private keys are managed by the harness, and the sub-agent only has signed permission to spend within the pre-defined policy bounds.
3. Fail-Closed Protocol
If the payment service (x402) is unreachable, the transaction MUST fail. CIEL agents MUST NOT attempt to bypass payment gates or fall back to unmetered access without explicit user authorization.
Workflow
- Pre-Check: Query remaining budget (
check_spending) before initiating any paid action. - Negotiation: Handle
402 Payment Requiredresponses by negotiating price and checking against the Per-Task Budget. - Execution: Invoke
send_paymentvia the designated MCP tool. - Audit: Log all transactions (
list_transactions) to the MemPalace Diary for session auditing.
Anti-Patterns
- Unlimited Spend: Delegating to an agent without a hard session budget.
- Self-Escalation: Allowing an agent to modify its own spending policy.
- Speculative Payment: Sending funds before receiving a verified
402or invoice.
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.
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.
- 1mo ago Changed · -13 lines 21e58e02e721
- 1mo ago First seen · 57 lines · 28 tokens per session scan A 490704aef5db
agent-payment-x402 is a skill published in the GitHub repository jxoesneon/Ciel (1 stars, last pushed 4d ago), licensed Apache-2.0. It adds 28 tokens to every session and 464 once invoked, about $0.0001 per session on Opus 5.5. 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 2026-08-31.
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