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v1.5 — Build the AI app

Every Claude Code user is, by definition, AI-app-curious. And until v1.5, opchain had zero owners for the part of a project where an LLM is actually in the loop. You could spec, design, build, audit, ship, and monitor a CRUD app with opchain — but the moment “and then Claude summarizes it” entered the picture, you were back to vibes.

v1.5 closes that gap. It adds four AI-native skills and wires them through the pipeline you already use, so the AI part gets the same idea → spec → build → ship → evaluate treatment as the rest of the app. The theme is one sentence:

Building with AI should be an engineering discipline, not a vibe.

The four new skills

Each owns one slice of an LLM feature, and each is built to make that slice a measured artifact instead of a hope.

  • oc-claude-api — the request surface. Model routing (Opus / Sonnet / Haiku / Fable by task), prompt caching on by default, tool-use patterns, and version-migration playbooks that produce a diff PR. When you move a model version, this skill gates the change instead of letting it silently drift.
  • oc-rag-forge — a tri-agent retrieval harness (Designer → Builder → Evaluator). It picks the vector DB, embedding model, and chunking strategy, then scores retrieval against a labelled set instead of eyeballing three queries that happen to work.
  • oc-agent-forge — a tri-agent build harness for Claude Agent SDK apps. It owns topology (single / orchestrator-worker / pipeline / hierarchical), tool budgets, and the harness loop — and gates the agent on a task-fixture suite, so “it worked when I tried it” stops being the bar.
  • oc-prompt-ops — prompts as code: versioned, diffable, and gated on an eval suite the same way application code is gated on tests. A prompt change becomes a reviewable diff with a measured score delta.

The ripples

The new skills don’t sit off to the side. They extend what was already there:

  • oc-stack-forge gained kind: vector-db packs: pgvector, Pinecone, Turbopuffer, and Supabase Vectors. Picking a vector store is now part of the same coverage registry as picking a language or a host.
  • oc-code-auditor learned an AI-safety pass — prompt-injection and tool-use-safety rules that only run when an LLM is in the loop. It traces untrusted content into prompts, and tool arguments into dangerous capabilities.
  • oc-app-architect /oc-discover now branches on “is this an AI app?” and routes through the four new skills automatically. You don’t have to know they exist; the orchestrator does.

How they chain

The point of a skillchain is that the pieces compose. A typical AI feature now flows like this:

  1. /oc-discover detects the AI surface and routes to oc-claude-api for model routing + caching defaults.
  2. If it’s retrieval-shaped, oc-rag-forge picks the vector DB (via the new stack-forge packs) and stands up an eval set.
  3. If it’s agentic, oc-agent-forge designs the topology and tool budget.
  4. oc-prompt-ops versions every prompt and gates changes on the eval suite.
  5. oc-code-auditor runs the AI-safety pass before you ship.

No single mega-prompt. Each skill does one job, writes a checkpoint, and hands off. (For the argument behind that design, see the engineering notes on evaluating instead of eyeballing.)

Dogfooding

opchain evaluates itself. The new prompts/opchain-eval/ set is a routing goldset — given a dev request, does opchain pick the right skill? — published as the worked example for /oc-prompt eval. We catch our own trigger-copy drift the same way we’d ask you to catch yours. The honest limits of that dogfooding are their own post.

The through-line

Every skill in this release makes the AI part of your app an evaluated artifact — measured, versioned, and safe to ship. That’s the whole bet of v1.5: the difference between a demo and a product is whether you can prove the AI part works, and prove it still works after you change it.

Browse the skill library or install opchain to start.

The opchain team

Builders of opchain

We build opchain — a skillchain and checkpoint protocol for shipping real software with Claude. We write about what we learn dogfooding it on our own pipeline.

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