Agents Honestly

Diagram Lab

Working reference for the four diagram components. Not part of the book.

Every figure below is the real content from The Agentic Engineer's Map, rendered through the components rather than as ASCII. Delete this page once the book's diagrams have been converted.

Layers

User
streams, approvals, interruptions
InterfacePart XIII
  • streaming
  • approvals
  • provenance
  • undo
intent
Agent RuntimeParts II, VII
modeldecidetoolobservedecide
  • state
  • memory
  • routing
  • subgraphs
  • stopping
what does it need to know?
Context & KnowledgeParts III–V
  • prompt
  • retrieval
  • memory
  • embeddings
  • SQL
  • graph
what should happen?
Durable ExecutionParts X–XII
  • retries
  • timers
  • signals
  • approval
  • compensation
effects on the real world
Tools & DataParts VI, VIII, IX
  • APIs
  • DBs
  • MCP
  • SaaS
External world

Cross-cutting

Evals · Observability · Reliability · SecurityParts XIV–XVII
  • none of the above is safe without them
Each layer owns a different kind of decision. Most production failures are a decision made at the wrong altitude.

Ladder

Who should own this state?

The model is choosing, reasoning, or judging
Agent Runtime
Conversation position, intermediate results, the plan
Graph stateLangGraph
A business process that must survive hours, days, deploys, crashes, and retries
WorkflowTemporal
Facts the business considers true
Database / APIs
Ask this before writing the code, not after the incident.

Decision

The task

Is the sequence known?

yes

Does it need to survive failure?

no

Function

yes

Workflow

no

Does it decide more than once?

no

Rules

yes

Agent

Is one context enough?

yes

One agent

no

Multi-agent

Every rung up costs latency, money, and predictability. Take one only when the rung below genuinely cannot do it.

Flow

  1. model
  2. decide
  3. tool
  4. observeresult enters context

until the model stops calling tools

The agent loop: the model keeps deciding until it stops asking for tools.

render card

inline in the session

the review queue

the audit record

An unlabelled fan-out is a Decision with no branch conditions.

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