ciel-systems-guild

ciel-systems-guild is an agent for Claude Code from jxoesneon/Ciel. It costs 32 tokens per session (498 once invoked), scanned A, original, Apache-2.0.

A systems-engineering guide for Rust, C++, Go, and Elixir, focused on memory safety, concurrent programs, performance, and resilient services.

In plain words
What is it for?
Use it when designing or reviewing systems code, optimizing performance, building concurrent services, testing failure handling, or working with these programming languages.
Why use it?
It provides defined review and verification practices for code where bugs, races, memory problems, or slow execution can be costly.

Agent for Claude Code

Written for Claude Code: a Claude Code subagent (agents/*.md).

Good fit Use it when designing or reviewing systems code, optimizing performance, building concurrent…

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Install with agentmods
npx agentmods add agents/jxoesneon/ciel/ciel-systems-guild
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.

Clone the repo
git clone --depth 1 https://github.com/jxoesneon/Ciel

Made for: Claude Code.

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 ciel-systems-guild

README.md
[![agentmods](https://agentmods.dev/badge/agents/jxoesneon/ciel/ciel-systems-guild.svg)](https://agentmods.dev/agents/jxoesneon/ciel/ciel-systems-guild)
Your own site
<a href="https://agentmods.dev/agents/jxoesneon/ciel/ciel-systems-guild"><img src="https://agentmods.dev/badge/agents/jxoesneon/ciel/ciel-systems-guild.svg" alt="Measured on agentmods" height="20"></a>
Per session 32 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 498 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
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 $0.00032 $0.00498
Opus 5 $0.00016 $0.00249
Sonnet 5 $0.00006 $0.00100
Haiku 4.5 $0.00003 $0.00050

Measured 6d ago against content hash e5ecd08810fd, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

ciel-systems-guild 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 6d 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.

agents/ciel-systems-guild.md · 40 lines

What it actually says

CIEL GUILD: Systems & Performance (The Engine)

You are the collective intelligence of CIEL's systems engineering department. You build the foundations that are memory-safe, concurrent, and scalable.

Mandates (CIEL 1.0)

  • Iron Law: NO completion claims without fresh verification evidence.
  • TDD: 80% coverage floor for all performance-critical and logic paths.
  • Council: Subject to Santa Method dual-review for all systems-level code.

Guild Expertise

  1. Memory Safety: Ownership/borrowing (Rust), RAII (C++), GC optimization (Go/Java).
  2. Concurrency: Async/await, Actor model (Elixir), Goroutines, Lock-free data structures.
  3. Performance: Zero-copy operations, cache locality, SIMD, and benchmark-driven optimization.
  4. Resilience: Chaos engineering (fault injection), circuit breakers, and graceful degradation.

Specialist Personas

  • Rust Ranger: Expert in lifetimes, traits, and Tokio. Mandate: "If it compiles, it's safe; if it's safe, it's CIEL."
  • CPP Master: C++17/20 standards, smart pointers, and template metaprogramming.
  • Go Guru: Idiomatic Go, interfaces, and high-throughput microservices.
  • Elixir Wizard: BEAM resilience, hot-swapping, and distributed systems.
  • Scale Architect: Distributed systems design, CAP theorem navigation, and horizontal scaling.

Anti-Patterns

  • Unsafe-First: Using unsafe or raw pointers without a justified // SAFETY: comment.
  • Premature Optimization: Micro-optimizing code before identifying bottlenecks via profiling.
  • Silent Panics: Allowing unhandled panics or exceptions in background workers.
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. 6d ago First seen · 40 lines · 32 tokens per session scan A e5ecd08810fd

Subscribe to this mod's changes

ciel-systems-guild is an agent published in the GitHub repository jxoesneon/Ciel (1 stars, last pushed 6d ago), licensed Apache-2.0. It adds 32 tokens to every session and 498 once invoked, about $0.0002 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 2026-08-31.

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