
AI Agents
Made Crystal Clear
A practical, visual guide to building agents that survive real users
Everyone is being told to build agents. Almost nobody is told what an agent actually is, how its loop really works, or why the demo that dazzled on Friday falls apart the moment a real user touches it on Monday. This guide takes you from zero to an agent you can trust: the loop, tools, context and memory, guardrails, evaluation, cost, and the honest list of jobs an agent should never be given. Patterns first, frameworks second, so what you learn outlives the next SDK release.
- Pages
- 223
- Level
- Beginner to advanced
- Status
- Available
Inside the book
- 01The Agent Moment, and the Gap Nobody Mentions
- 02What an Agent Actually Is
- 03When NOT to Build an Agent
- 04Your First Agent, From Scratch
- 05Tools, the Agent's Hands
- 06Context and Memory
- 07MCP, Plugging In the World
- 08The Production Cliff
- 09Guardrails, Budgets and Stop Conditions
- 10The Trust Boundary
- 11Proving It Works: Evals
- 12Debugging a Failed Run
- 13The Money Chapter
- 14Frameworks, Multi-Agent, and What to Learn Next
You'll leave with
- Understand the agent loop: goal, context, decision, tool call, observation, stop
- Ship your first working agent, then make it fail on purpose to see why
- Tell an agent from a workflow, and know when not to build one at all
For teams
Put AI Agents on every desk at your company.
One licence, every book in the series, one link for everyone. From $250 a year.
Sources
Every source cited in AI Agents Made Crystal Clear. Each number matches the [n] marker next to that link in the book's "Go deeper" lists, so you can trace any claim back to its origin.
- [1]Building effective agents (Anthropic Engineering)
- [2]12-Factor Agents (HumanLayer)
- [3]Production-ready AI agents: 5 lessons from refactoring a monolith (Google Developers, 21 April 2026)
- [4]A practical guide to building agents (OpenAI, PDF, 33 pages)
- [5]The agent loop (Claude Agent SDK docs)
- [6]Claude Agent SDK overview
- [7]Running agents (OpenAI Agents SDK)
- [8]OpenAI Agents SDK overview
- [9]r/AI_Agents
- [10]Tool use overview (Anthropic)
- [11]Defining tools (Anthropic)
- [12]Agents (OpenAI Agents SDK)
- [13]Writing tools for agents (Anthropic Engineering)
- [14]OpenAI Agents SDK: tools
- [15]Context Rot: How Increasing Input Tokens Impacts LLM Performance (Chroma, 14 July 2025)
- [16]Effective context engineering for AI agents (Anthropic, 29 September 2025)
- [17]Claude Agent SDK: subagents
- [18]Prompt caching (Anthropic)
- [19]Architecture overview (modelcontextprotocol.io)
- [20]Architecture, specification revision 2026-07-28
- [21]Server concepts
- [22]Tools, specification revision 2026-07-28
- [23]Security best practices, revision 2026-07-28
- [24]Security best practices, revision 2025-11-25
- [25]Specification index
- [26]How we built our multi-agent research system (Anthropic, 13 June 2025)
- [27]Don't build multi-agents (Cognition, 12 June 2025)
- [28]Permissions (Claude Agent SDK)
- [29]Guardrails (OpenAI Agents SDK)
- [30]Pricing (Anthropic)
- [31]OWASP LLM01:2025 Prompt Injection
- [32]OWASP Top 10 for LLM Applications 2025 (PDF)
- [33]OWASP Securing Agentic Applications Guide 1.0
- [34]The lethal trifecta for AI agents (Simon Willison, 16 June 2025)
- [35]The Dual LLM pattern (Simon Willison, 25 April 2023)
- [36]Design patterns for securing LLM agents (Willison on Beurer-Kellner et al., 13 June 2025)
- [37]Willison's prompt-injection tag
- [38]Mitigating the risk of prompt injections in browser use (Anthropic, 24 November 2025)
- [39]Not what you've signed up for: Compromising Real-World LLM-Integrated Applications with Indirect Prompt Injection (arXiv:2302.12173)
- [40]Demystifying evals for AI agents (Anthropic Engineering, 9 January 2026)
- [41]tau-bench (17 June 2024)
- [42]tau2-bench: Evaluating Conversational Agents in a Dual-Control Environment (9 June 2025)
- [43]sierra-research/tau2-bench (GitHub)
- [44]SWE-bench: Can Language Models Resolve Real-World GitHub Issues? (October 2023)
- [45]What skills does SWE-bench Verified evaluate? (Epoch AI, 13 June 2025)
- [46]SWE-bench Verified harness details (Epoch AI)
- [47]GenAI spans, OpenTelemetry semantic conventions
- [48]GenAI agent spans
- [49]GenAI metrics
- [50]Inside the LLM Call: GenAI Observability with OpenTelemetry
- [51]Tracing, OpenAI Agents SDK
- [52]OpenAI API pricing (official)
- [53]Google Gemini API pricing (official)
- [54]LangChain pricing
- [55]n8n pricing
- [56]Zapier pricing
- [57]LangGraph overview
- [58]LangGraph persistence
- [59]CrewAI crews
- [60]CrewAI flows
- [61]Pydantic AI overview
- [62]Mastra agents
Also in the series
35 more titles, one tool or topic each. Swipe or use the arrows.
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