LLM Agents Ecosystem Handbook

A practical operating manual for building, evaluating, securing, and shipping modern LLM agent systems.

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Modern agents are not "a prompt + a tool." They are systems — with identity, memory, skills, tools, MCP integrations, guardrails, observability, evals, and a provider strategy. This handbook teaches the whole stack and ships templates, blueprints, runnable adapters, and curated examples you can adopt today.

What's in this repo

A curated, opinionated, production-oriented handbook in seven parts:

1. Concepts — Agent OS, identity, memory, skills, MCP, safety, observability — every layer of the modern agent stack
2. Provider ecosystem — adapters + docs for 24+ LLM providers (frontier APIs, fast inference, marketplaces, enterprise clouds, specialty, local runtimes), with a router for fallback chains
3. Skills ecosystem — design guide, taxonomy, maturity model, security checklist, and a curated skill catalog
4. Prompt engineering — agent prompt patterns, instruction hierarchy, context engineering, prompt-injection defense
5. Coding-agent workflows — for Claude Code, Cursor, Codex, Aider, Cline, and custom runtimes — repo instructions, prompts, review checklist, safe refactoring
6. Design docs — agent / technical design docs, ADR guide, design reviews, rollout plans, the DESIGN.md machine-readable spec
7. Curated catalog — 100+ existing agent skeletons, framework comparisons, evaluation tools, tutorials — preserved and improved

Who this is for

You are…	Start at
New to agents	docs/beginners_guide.md → agent_os/README.md
Building a production agent	blueprints/ → checklists/production_readiness_checklist.md
Picking / wiring providers	providers/README.md → providers/provider_matrix.md
Comparing frameworks	docs/framework_comparison.md
Adding memory / RAG	memory/ → tutorials/rag_tutorials
Adding MCP	mcp/ → mcp/mcp_security.md
Designing Skills	skills/ → skills/skill_design_guide.md
Working with coding agents	coding_agents/ → coding_agents/prompts/
Writing better prompts	prompt_engineering/
Designing & rolling out	design_docs/
Hardening safety/evals	safety/ → evals/
Coding agent reading this repo	llms.txt → llm_wiki/index.md

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Modern Agent Stack