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Engineering handbook
AI Agent Engineering Handbook

Start with tool calls. Understand how an agent acts, reads observations and stops when something fails. Verify each boundary with complete code and offline tests.

5 chapters·16 guides·Open access
The Agent Ecosystem in 2026
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Understanding the Agent Ecosystem

Compare agent tools by the work they control. A coding interface, orchestration framework and hosted platform solve different parts of the problem; a single ranking hides those differences.

#IDE and coding interfaces

Tools such as Cursor, Claude Code and GitHub Copilot work close to source code. Evaluate repository discovery, patch review, test execution and permission boundaries. Inspect an actual diff and resulting behavior, rather than judging only the generated explanation.

Product capabilities and plans change. This chapter describes categories, not an exhaustive current feature comparison or a claim that every tool supports every workflow.

#Frameworks

LangChain provides model and tool composition. LangGraph makes state and routing explicit. Role-oriented frameworks such as CrewAI can illustrate handoffs between research and writing. Choose the abstraction that makes your failure cases easier to control.

A framework does not automatically provide safe tools, good evidence, tenant isolation or reliable deployment. Those remain application responsibilities.

#Hosted platforms

Platforms can supply model access, managed state, connectors and operational controls. Before selecting one, verify available regions, identity integration, data retention, exportability and the ability to inspect a failed run. A visual workflow editor is useful only when its execution semantics match the task.

#Infrastructure is part of the decision

Retrieval, evaluation datasets, tracing, secret management and sandboxes often determine whether an agent is usable. Budget for these alongside model calls. Prefer a fixed workflow when the sequence is already known.

For a small pilot, write one acceptance task and two failure cases first. Compare completion quality, recoverability, latency and total cost using the same inputs. Keep the smallest system that passes; add roles or services when a measured gap justifies them.

Agent architecture · LangChain learning resources↗

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Core system design concepts and practical case studies

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FAQ

Which language should I use?
Python and TypeScript both work. Start with the language you can debug; the first exercise uses Python 3.10+ and its standard library.
Does MCP require a specific model?
No. MCP connects applications to tools and context services. Compatibility depends on the host client, transport, protocol version and authorisation; model tool-calling support is a separate check.
Does learning agents guarantee employment?
No. Use a small project to demonstrate requirements analysis, permissions, testing and maintenance. Employment outcomes depend on the role market and your actual skills.

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