Career roadmap
AI Agent Engineer
Build LLM systems that take actions, use tools and recover from their own mistakes without a human watching.
Before you start Agent Engineer
- Backend engineering experience
- Familiarity with LLM APIs and prompting
- Understanding of async programming
Foundations of agentic systems
An agent is a control loop around a model. Understanding the loop is the whole job.
Frameworks hide this. Interviews expect you to be able to write it yourself.
- Observe, decide, act, repeat
- Termination conditions and step limits
- State between iterations
- Why loops fail to terminate
Tool definitions are prompts. Their design determines reliability.
- Tool schemas and descriptions that work
- Parameter validation and coercion
- Error messages the model can act on
- Limiting the tool surface
Agent prompts differ from chat prompts: they must constrain behaviour, not just style.
Ch — Prompt Engineering- System prompt structure for agents
- Reasoning and planning prompts
- Output format enforcement
- Prompt versioning and testing
Capability, latency and cost differ enormously and change monthly.
- Reasoning models versus fast models
- Routing between models by task
- Context window management
- Provider differences in tool calling
Most production agents end up with less framework than they started with.
- What agent frameworks actually provide
- Debuggability versus convenience
- MCP and tool interoperability
- Building your own minimal harness
BuildBuild a tool-using agent from scratch, without a framework, that completes a multi-step task.
Memory and context
Context management is the practical bottleneck in every real agent.
Context is a budget. Spending it well is the core engineering discipline.
- Token budgeting per component
- Compaction and summarisation strategies
- What to drop first
- Measuring context efficiency
Short-term, long-term and episodic memory, and the retrieval that makes them useful.
- Conversation memory and summarisation
- Persistent memory stores
- Retrieval for memory versus documents
- Memory staleness and conflicts
Agents need retrieval on demand, not one shot at the start.
Ch — RAG- Retrieval as a tool the agent calls
- Query rewriting and decomposition
- Reranking and result formatting
- Grounding and citation
Long-running agents must survive restarts, which most tutorials ignore.
- Externalising agent state
- Checkpointing and resumption
- Idempotent tool execution
- Handling partial completion
Reliable parsing is what lets an agent integrate with real systems.
- Schema-constrained generation
- Validation and repair loops
- Typed tool results
- Handling schema violations
BuildAn agent that handles a long task without exceeding context, with a documented compaction strategy.
Reliability
The gap between a demo and a product is entirely about failure handling.
Without an eval set you are guessing. This is the single biggest differentiator.
Ch — Evaluation & Hallucination- Task success definitions
- Building a regression suite of scenarios
- Trajectory evaluation versus outcome
- LLM-as-judge and its limits
Agents fail in recognisable, catalogued ways. Knowing them speeds diagnosis.
- Loops and repeated actions
- Tool misuse and hallucinated parameters
- Premature termination
- Context poisoning from bad results
Good agents recover; great ones do it without a human noticing.
- Retry with modified approach
- Backtracking and replanning
- Escalation to a human
- Partial success handling
Deterministic checks around a non-deterministic core.
- Preconditions and postconditions on tools
- Permission and approval gates
- Budget and step limits
- Deterministic validation of outputs
Often proposed, rarely necessary. Knowing when it helps is the senior signal.
- Orchestrator and sub-agent patterns
- Context isolation between agents
- Coordination cost and latency
- When one agent is better
BuildTake an agent from a 60% task success rate to over 90%, with the evaluation to prove it.
Production agents
Cost, latency, security and observability for systems that act autonomously.
You cannot debug an agent from logs alone. Traces are mandatory.
- Full trajectory tracing
- Token and cost attribution per step
- Replaying a failed run
- Dashboards for agent health
Agents multiply token usage. Cost surprises are the usual reason they get cancelled.
Ch — Cost & Latency- Cost per completed task
- Caching and prompt reuse
- Model routing for cheap steps
- Parallel tool execution
An agent with tools is an attack surface with credentials.
Ch — AI Security- Prompt injection through tool results
- Least privilege for tool credentials
- Sandboxing code execution
- Confused deputy problems
Deciding what requires approval is a product and a safety decision.
- Approval gates for risky actions
- Confidence-based escalation
- Reviewing agent decisions
- Audit trails for autonomous actions
Agents are long-running, stateful and bursty, which complicates deployment.
- Background jobs versus request/response
- Queueing and concurrency limits
- Timeout and cancellation
- Versioning agents safely
BuildDeploy an agent with full tracing, cost tracking, and a security review of its tool permissions.
Interview preparation
Interviews focus on reliability engineering, not on prompt cleverness.
Design an agent for a real workflow, with failure handling front and centre.
- Tool decomposition for a task
- Context and memory design
- Failure and escalation paths
- Cost and latency estimates
Here is a failing trajectory. What went wrong and how would you fix it.
- Reading a trace to find the failure point
- Distinguishing prompt, tool and model issues
- Proposing a targeted fix
- Preventing regression
Implement an agent loop with tools, without a framework.
- Writing the loop and tool dispatch
- Error handling and retries
- Structured output parsing
- Testing non-deterministic code
How would you know this agent got better. The question that separates candidates.
- Designing a task success metric
- Building an eval set from production traces
- Handling non-determinism in tests
- Measuring regression across versions
Reliability numbers are the currency. Demos without them are ignored.
- An agent with a published success rate
- The evaluation suite alongside it
- A reliability improvement case study
- Cost per task tracked over versions
BuildA public agent project with an evaluation suite and a written reliability report.
Agent Engineer tools on your CV
- Claude / OpenAI APIs
- MCP
- LangGraph
- Vector databases
- OpenTelemetry / LangFuse
- Pydantic
- Python / TypeScript
What Agent Engineer employers ask to see
- An agent with a published task success rate and eval suite
- A reliability case study: failure taxonomy and fixes
- A tool permission and security review write-up
- Cost per completed task tracked across versions
The fastest-moving specialism in applied AI. Every company that shipped a chatbot in 2024 is now trying to ship an agent, and few engineers have done it reliably.
Content last reviewed 2026-08-31. Guidance only — no institute or paid placement is endorsed anywhere in this book.