Practical notes: Agentic Architectures — Article 15: The Maturity Model

This walkthrough rebuilds the path from raw materials to a working system for: Agentic Architectures — Article 15: The Maturity Model Revisited. The focus is operable steps, explicit checks, and code that you can drop into a repo without guessing intent. For the Overview stage, define the inputs, the owner of the step, and the exit criteria before changing code. Operators should be able to re-run the step from a known checkpoint without guessing hidden state. Treat this stage as a contract between inputs and validated outputs. Name the artifacts, define success checks, and refuse silent partial completion.

What You’ll Find Here

When working through the What You ll Find stage, write down the contract first: required inputs, success signal, and what happens on partial failure. That checklist keeps later code changes honest. Record timings and token or query cost next to functional results. Cost visibility early prevents surprise bills when the path moves from demo to shared environments. Cache stable system instructions and tool schemas. Re-sending identical preamble is a common source of burn.

The Maturity Model, Seen Again

When working through the The Maturity Model Seen stage, write down the contract first: required inputs, success signal, and what happens on partial failure. That checklist keeps later code changes honest. Keep configuration outside application code. Environment files, secret stores, and feature flags belong in one place operators can audit without reading the whole graph. Cache stable system instructions and tool schemas. Re-sending identical preamble is a common source of burn.

+---------+---------------------+------------------------------------------+
| Level   | Capability          | Articles That Build It                   |
+---------+---------------------+------------------------------------------+
| Level 1 | Reactive            | Article 4: Protocols (MCP, A2A)          |
|         | Responds to inputs, | Basic tool use, standard interfaces      |
|         | calls tools         |                                          |
+---------+---------------------+------------------------------------------+
| Level 2 | Assisted            | Article 5: Harness Engineering           |
|         | Shaped behavior,    | Article 13: Human-in-the-Loop            |
|         | human oversight     |                                          |
+---------+---------------------+------------------------------------------+
| Level 3 | Supervised          | Article 6: Multi-Agent Orchestration     |
|         | Coordinated,        | Article 8: Evaluation Pipelines          |
|         | evaluated, secured  | Article 9: Security and Red-Teaming      |
+---------+---------------------+------------------------------------------+
| Level 4 | Autonomous          | Article 7: Memory Architectures          |
|         | Operates            | Article 10: Cost Optimization            |
|         | independently at    | Article 11: Deployment Patterns          |
|         | scale               | Article 14: Goal-Directed Loops          |
+---------+---------------------+------------------------------------------+
| Level 5 | Self-Improving      | Articles 7 + 8 combined                  |
|         | Learns from its own | Article 12: The frontier (not yet here)  |
|         | operation           |                                          |
+---------+---------------------+------------------------------------------+

What Changed in the Thinking

When working through the What Changed in the stage, write down the contract first: required inputs, success signal, and what happens on partial failure. That checklist keeps later code changes honest. Document the happy path and the recovery path together. Retries, human gates, and dead-letter handling are part of the product, not later polish. Cache stable system instructions and tool schemas. Re-sending identical preamble is a common source of burn. When working through the What Changed in the stage, write down the contract first: required inputs, success signal, and what happens on partial failure. That checklist keeps later code changes honest. Treat this stage as a contract between inputs and validated outputs. Name the artifacts, define success checks, and refuse silent partial completion.

The Layers That Compound

The The Layers That Compound stage works best when treated as a measurable surface. Capture one golden transcript, one failure case, and the rollback note before expanding scope. Record timings and token or query cost next to functional results. Cost visibility early prevents surprise bills when the path moves from demo to shared environments. Budget tokens per turn and per session. Agentic tools expand context aggressively; hard caps keep demos from becoming surprise invoices.

+==========================================================================+
|                          HUMAN OVERSIGHT LAYER                           |
|          Approval gates, escalation, audit trail  (Article 13)          |
+==========================================================================+
              |                    |                    |
+==========================================================================+
|                            GOAL & LOOP LAYER                            |
|      ReAct / Plan-Execute / Reflexion, goal revision  (Article 14)     |
+==========================================================================+
              |                    |                    |
+==========================================================================+
|                          ORCHESTRATION LAYER                            |
|      Supervisor-worker, pipeline, fan-out, debate  (Article 6)         |
+==========================================================================+
              |                    |                    |
+==========================================================================+
|                            HARNESS LAYER                                |
|   Self-verification, loop detection, reasoning routing  (Article 5)    |
+==========================================================================+
              |                    |                    |
+--------------------------------------------------------------------------+
|                             MODEL LAYER                                 |
|              AWS Bedrock: Claude 3.7 / 3.5 / Haiku                      |
+--------------------------------------------------------------------------+

  CROSS-CUTTING CONCERNS (touch every layer above):

  +----------------+  +----------------+  +----------------+  +----------------+
  | MEMORY         |  | EVALUATION     |  | SECURITY       |  | COST           |
  | Article 7      |  | Article 8      |  | Article 9      |  | Article 10     |
  | episodic,      |  | offline+online |  | injection def, |  | model routing, |
  | semantic,      |  | LLM judge,     |  | guardrails,    |  | caching,       |
  | procedural     |  | regression     |  | red-teaming    |  | batch, budget  |
  +----------------+  +----------------+  +----------------+  +----------------+

  +--------------------------------------------------------------------------+
  |                          DEPLOYMENT LAYER (Article 11)                   |
  |     Blue-green, canary, state migration, model pinning, IaC             |
  +--------------------------------------------------------------------------+

What Is Still Unsolved

The What Is Still Unsolved stage works best when treated as a measurable surface. Capture one golden transcript, one failure case, and the rollback note before expanding scope. Keep configuration outside application code. Environment files, secret stores, and feature flags belong in one place operators can audit without reading the whole graph. Budget tokens per turn and per session. Agentic tools expand context aggressively; hard caps keep demos from becoming surprise invoices.

How to Use This Series

The How to Use This stage works best when treated as a measurable surface. Capture one golden transcript, one failure case, and the rollback note before expanding scope. Document the happy path and the recovery path together. Retries, human gates, and dead-letter handling are part of the product, not later polish. Budget tokens per turn and per session. Agentic tools expand context aggressively; hard caps keep demos from becoming surprise invoices. The How to Use This stage works best when treated as a measurable surface. Capture one golden transcript, one failure case, and the rollback note before expanding scope. Treat this stage as a contract between inputs and validated outputs. Name the artifacts, define success checks, and refuse silent partial completion.

A Note on the Tools

For the A Note on the stage, define the inputs, the owner of the step, and the exit criteria before changing code. Operators should be able to re-run the step from a known checkpoint without guessing hidden state. Record timings and token or query cost next to functional results. Cost visibility early prevents surprise bills when the path moves from demo to shared environments. Prefer structured outputs with schema validation over free-form prose when the next step is code or a tool call.

Closing Reflection

For the Closing Reflection stage, define the inputs, the owner of the step, and the exit criteria before changing code. Operators should be able to re-run the step from a known checkpoint without guessing hidden state. Keep configuration outside application code. Environment files, secret stores, and feature flags belong in one place operators can audit without reading the whole graph. Prefer structured outputs with schema validation over free-form prose when the next step is code or a tool call.

Operational checklist

The Operational checklist stage works best when treated as a measurable surface. Capture one golden transcript, one failure case, and the rollback note before expanding scope.

Prefer small, testable units over sprawling scripts. When a step fails, the failure should point at a single responsibility rather than a tangled pipeline.

Budget tokens per turn and per session. Agentic tools expand context aggressively; hard caps keep demos from becoming surprise invoices.

Put human approval on edges that spend money or change production data. Compile-time wiring does not equal business completeness.

Write a short runbook: how to rotate keys, how to drain the queue, how to roll back the last ingest.

Keep configuration outside application code. Environment files, secret stores, and feature flags belong in one place operators can audit without reading the whole graph.

Before promoting the stack, freeze versions, capture a golden transcript for the critical path, and confirm rollback steps. Shared environments need rate limits, tenancy checks, and a clear owner for secret rotation. Prefer boring reliability over clever one-off demos.

Batch note for f4d1cdcaf736: keep provider keys out of the repo, set a per-session token ceiling, and store transcripts next to the eval fixtures so later model swaps stay comparable.

For the hardening note 0 stage, define the inputs, the owner of the step, and the exit criteria before changing code. Operators should be able to re-run the step from a known checkpoint without guessing hidden state. Keep configuration outside application code. Environment files, secret stores, and feature flags belong in one place operators can audit without reading the whole graph.

Hardening detail 0/960: measure wall time, error class, and token spend for this note, then decide whether to keep the change based on a fixed question set rather than anecdote.

When working through the hardening note 1 stage, write down the contract first: required inputs, success signal, and what happens on partial failure. That checklist keeps later code changes honest. Prefer small, testable units over sprawling scripts. When a step fails, the failure should point at a single responsibility rather than a tangled pipeline.

Hardening detail 1/960: measure wall time, error class, and token spend for this note, then decide whether to keep the change based on a fixed question set rather than anecdote.

The hardening note 2 stage works best when treated as a measurable surface. Capture one golden transcript, one failure case, and the rollback note before expanding scope. Record timings and token or query cost next to functional results. Cost visibility early prevents surprise bills when the path moves from demo to shared environments.

Hardening detail 2/960: measure wall time, error class, and token spend for this note, then decide whether to keep the change based on a fixed question set rather than anecdote.

For the hardening note 3 stage, define the inputs, the owner of the step, and the exit criteria before changing code. Operators should be able to re-run the step from a known checkpoint without guessing hidden state. Document the happy path and the recovery path together. Retries, human gates, and dead-letter handling are part of the product, not later polish.

Hardening detail 3/960: measure wall time, error class, and token spend for this note, then decide whether to keep the change based on a fixed question set rather than anecdote.

When working through the hardening note 4 stage, write down the contract first: required inputs, success signal, and what happens on partial failure. That checklist keeps later code changes honest. Treat this stage as a contract between inputs and validated outputs. Name the artifacts, define success checks, and refuse silent partial completion.

Hardening detail 4/960: measure wall time, error class, and token spend for this note, then decide whether to keep the change based on a fixed question set rather than anecdote.

The hardening note 5 stage works best when treated as a measurable surface. Capture one golden transcript, one failure case, and the rollback note before expanding scope. Keep configuration outside application code. Environment files, secret stores, and feature flags belong in one place operators can audit without reading the whole graph.

Hardening detail 5/960: measure wall time, error class, and token spend for this note, then decide whether to keep the change based on a fixed question set rather than anecdote.

For the hardening note 6 stage, define the inputs, the owner of the step, and the exit criteria before changing code. Operators should be able to re-run the step from a known checkpoint without guessing hidden state. Prefer small, testable units over sprawling scripts. When a step fails, the failure should point at a single responsibility rather than a tangled pipeline.

Hardening detail 6/960: measure wall time, error class, and token spend for this note, then decide whether to keep the change based on a fixed question set rather than anecdote.

When working through the hardening note 7 stage, write down the contract first: required inputs, success signal, and what happens on partial failure. That checklist keeps later code changes honest. Record timings and token or query cost next to functional results. Cost visibility early prevents surprise bills when the path moves from demo to shared environments.

Hardening detail 7/960: measure wall time, error class, and token spend for this note, then decide whether to keep the change based on a fixed question set rather than anecdote.

The hardening note 8 stage works best when treated as a measurable surface. Capture one golden transcript, one failure case, and the rollback note before expanding scope. Document the happy path and the recovery path together. Retries, human gates, and dead-letter handling are part of the product, not later polish.

Hardening detail 8/960: measure wall time, error class, and token spend for this note, then decide whether to keep the change based on a fixed question set rather than anecdote.

For the hardening note 9 stage, define the inputs, the owner of the step, and the exit criteria before changing code. Operators should be able to re-run the step from a known checkpoint without guessing hidden state. Treat this stage as a contract between inputs and validated outputs. Name the artifacts, define success checks, and refuse silent partial completion.

Hardening detail 9/960: measure wall time, error class, and token spend for this note, then decide whether to keep the change based on a fixed question set rather than anecdote.

When working through the hardening note 10 stage, write down the contract first: required inputs, success signal, and what happens on partial failure. That checklist keeps later code changes honest. Keep configuration outside application code. Environment files, secret stores, and feature flags belong in one place operators can audit without reading the whole graph.

Hardening detail 10/960: measure wall time, error class, and token spend for this note, then decide whether to keep the change based on a fixed question set rather than anecdote.

The hardening note 11 stage works best when treated as a measurable surface. Capture one golden transcript, one failure case, and the rollback note before expanding scope. Prefer small, testable units over sprawling scripts. When a step fails, the failure should point at a single responsibility rather than a tangled pipeline.

Hardening detail 11/960: measure wall time, error class, and token spend for this note, then decide whether to keep the change based on a fixed question set rather than anecdote.