building-agent-systems

A reference for designing AI agents and systems that use large language models, the technology behind many text-based AI tools. It covers single agents, groups of agents, information retrieval, prompts, testing, and security.

In plain words
What is it for?
Use it when building tool-using agents, multi-agent systems, retrieval-based applications, prompt tests, or protections against prompt injection and other AI-specific attacks.
Why use it?
It helps developers choose an appropriate system design and account for risks such as malicious instructions, unreliable answers, and untested prompts. It also explains when a simple workflow is enough and when several agents may help.

Skill for Claude CodeCodex

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.

agentmods
npx agentmods add skills/telagod/code-abyss/building-agent-systems
Any agent
npx skills add telagod/code-abyss --skill building-agent-systems
Clone the repo
git clone --depth 1 https://github.com/telagod/code-abyss

Made for: Claude Code, Codex.

Per session 110 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,101 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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 $0.00110 $0.01101
Opus 5 $0.00055 $0.00550
Sonnet 5 $0.00022 $0.00220
Haiku 4.5 $0.00011 $0.00110

Measured 2d ago against content hash 9925ca074319, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

building-agent-systems 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 2d 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.

skills/building-agent-systems/SKILL.md · 70 lines

How it starts

The opening of the file, as written. The whole thing — 70 lines — stays where its author put it; the contents beside it link to each section on GitHub.

丹鼎秘典 · Agent / LLM 工程

判断先于执行:决定「是否做 / 选什么 / 如何取舍」(栈、方案、架构、权衡)前,先读领域判断内核 skills/_kernel/ml/SKILL.md——它管 judgment,本秘典管 execution;冲突时以内核判断为准。

单 Agent 是器,多 Agent 是阵。先选规模,再选模式。

路由

意图 加载 核心
单 Agent 开发(工具调用、ReAct) agent-dev ReAct / Plan-Execute / Reflection
多 Agent 协同(>=3 文件 or >=2 并行) multi-agent-coordination 蚁群仿生、文件锁、依赖图
多 Agent 协议细节(消息素、收阵报告) multi-agent-protocol Codex 原生协议、角色定义
LLM 安全(注入、越狱、输出过滤) llm-security OWASP LLM Top 10 视角
RAG 系统(向量、检索、重排) rag-system Chunking / 混合检索 / Cohere rerank
Prompt + 评估 prompt-and-eval Few-shot / CoT / RAGAS / LLM-as-Judge

规模决策

单步任务(一文件、一查询)         → 直接执行(不需要 Agent 框架)
多步任务(计划 + 工具)             → 单 Agent (ReAct)
复杂任务(>5 步、需反思)           → 单 Agent (Plan-Execute / Reflection)
独立并行任务(>=3 文件、>=2 流)    → 多 Agent (TeamCreate)
跨域协作(角色明确)                → 多 Agent (角色分工)

犹豫时优先 TeamCreate — 串行降级容易,并行升级难。

通用原则

Prompt 即代码须版控 | 输入输出皆验证 | 成本效果平衡 | 持续评估迭代 | 安全边界明确

跨场景铁律

  1. Prompt 版控 — Prompt 是代码,必须 Git;变更要走 review
  2. I/O 验证 — 输入侧防注入,输出侧防 hallucination 落地(结构化 schema、引用追溯)
  3. 评估前置 — 上线前必有 eval set;RAGAS / LLM-as-Judge 至少二选一
  4. 成本观测 — token / latency / 失败率必埋点;预算阈值自动告警
  5. 降级路径 — 多 Agent 失败 → 单 Agent;单 Agent 失败 → 直接回答 + 标记 [unverified]

多 Agent 启用判据

信号 启用 TeamCreate
涉及 ≥3 独立文件
需 ≥2 并行流
总步骤 >10
用户明确要求
单一探索任务 ❌(用 explorer 或单 Agent)
单文件改动 ❌(用 worker 或直接执行)
单步任务 ❌(直接执行)

详细生命周期、文件锁规则、依赖感知、过载保护、降级链:multi-agent-coordination.md

与其他 skill 联动

Read the full file on GitHub · 70 lines

Files

What ships with it

6 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.

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. 2d ago First seen · 70 lines · 110 tokens per session scan A 9925ca074319

Subscribe to this mod's changes

building-agent-systems is a skill published in the GitHub repository telagod/code-abyss (239 stars, last pushed 1mo ago), licensed MIT. It adds 110 tokens to every session and 1,101 once invoked, about $0.0006 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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