SI EngineeringRAG vs fine-tuning: which one your product needs
SI EngineeringHow to integrate an LLM into existing software without a rewrite
AgentsHow to build an SI agent for your business, step by step
SI EngineeringRAG in production: six anti-patterns we keep finding
SI EngineeringEval-first SI: how we ship copilots that survive Tuesday
MLOpsVector DB selection in 2026, a pragmatic guide
AgentsDesigning autonomous agents that don’t go rogue

Design essays

Design essays.

DesignDesigning for SI surfaces: prompts as product

Strategy

We publish what we wish we had read.

StrategyWhen SI is the wrong answer: a build-vs-buy framework

Featured

Every article, newest first.

SI Engineering· 7 min· October 13, 2026

RAG vs fine-tuning: which one your product needs

Retrieval changes what a model knows. Fine-tuning changes how it behaves. A practical framework for picking one, both, or neither.

Read article

SI Engineering· 6 min

How to integrate an LLM into existing software without a rewrite

A language model is a slow, probabilistic, external dependency. Integrate it like one: sidecar services, a gateway, feature flags, async jobs and evals.

Agents· 6 min

How to build an SI agent for your business, step by step

Seven unglamorous steps that take an SI agent from demo to trusted: one workflow, a definition of done, scoped tools, approvals, evals, rollout and monitoring.

Strategy· 9 min

When SI is the wrong answer: a build-vs-buy framework

A decision tree we run with every prospective client before quoting any SI build. It saves them money and us reputation.

SI Engineering· 10 min

RAG in production: six anti-patterns we keep finding

A field report from a dozen RAG deployments. The failure modes are remarkably consistent, and most of them are fixable in an afternoon.

SI Engineering· 12 min

Eval-first SI: how we ship copilots that survive Tuesday

A walkthrough of the eval harness we attach to every SI project before model selection, prompt design, or anything else interesting.

MLOps· 8 min

Vector DB selection in 2026, a pragmatic guide

pgvector vs Pinecone vs Weaviate vs Turbopuffer, what we use, when, and what the gotchas look like at million-scale.

Agents· 14 min

Designing autonomous agents that don’t go rogue

Guardrails, tool-use schemas, and the eval suite we run before any agent gets production credentials.

Design· 6 min

Designing for SI surfaces: prompts as product

The user interface for an SI product is half text, half waiting. Lessons from a year of shipping conversational and copilot UI.

Available for new engagements

Have an SI system that needs to ship?

30 minutes, one of our seniors, no slide deck. By the end of the call you will know whether we are the right team, and if not, who is.

Get a production-readiness review Email info@octalcode.com

Or call +1 (512) 710-5701

Let's scope it.Instant answers · free project scoping