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"Local-first CI: CI in the age of AI"

February 4, 2026 · 7 min read

AI can write code in seconds. Your CI takes 20 minutes to tell you it's wrong.

As AI accelerates how fast we produce code, cloud CI has become the slowest part of the feedback loop. There's a better way.

The Problem: Cloud CI's Hidden Latency Tax

  • The old workflow: write → push → wait → fix → repeat

  • Cloud CI latency was acceptable when humans were the bottleneck

  • AI-assisted development inverts this—code generation is fast, feedback is slow

  • Real cost: context switching, lost flow state, compounding errors

What is Local-first CI?

  • Definition: Your full CI pipeline runs locally with a single command

  • Not just "running tests locally"—the entire pipeline: lint, build, test, integration

  • The key property: what passes locally will pass in CI

  • This requires reproducibility—same result everywhere

The Reproducibility Problem

  • Why "it works on my machine" exists: different environments

  • Traditional solutions: Docker, CI config, prayer

  • Nix: hermetic builds that guarantee identical results

  • Nix pins everything—compilers, libraries, tools

  • Single command: nix flake check runs your entire CI locally

The New Workflow: AI + Local-first CI

  • Old: write → push → wait 20 min → CI fails → context switch → fix

  • New: AI writes code → local CI in 2 min → fix immediately → push with confidence

  • Example: Claude refactors a module, local CI catches a lint error, fix before pushing

But What About Heavy Builds?

  • Local-first doesn't mean local-only

  • Hybrid model: fast local checks + distributed heavy lifting

  • Binary caching: builds only happen once, then cached

  • NixCI: self-hosted workers pull from your binary cache

Self-Hosted: Control Your Destiny

  • Cloud CI vendor lock-in (and billing surprises)

  • Your code on your machines

  • Workers behind NATs—no public IP required

  • No usage caps during crunch time

Conclusion: CI for the AI Era

  • AI will only get faster at generating code

  • Your feedback loop needs to keep up

  • Local-first CI closes the gap

Analysis: Answering the Reader's Two Questions

Core Problem

The outline has a strong hook but doesn't adequately answer two questions every reader asks:

  1. "Is this relevant to me?" — Target audience unclear, Nix pivot is jarring

  2. "Is this worth my time?" — No credibility, no evidence, weak stakes, abrupt product mention

Clarified Context

  • Audience: Nix-curious developers (heard of Nix, might adopt it)

  • Goal: Thought leadership (establish "local-first CI" as a concept)

  • Evidence: Concrete data available to include

Recommended Changes

1. Add an explicit audience signal after the hook

After the intro, add a line like:

"If you're an engineer shipping code with AI assistance—and watching CI queues eat your momentum—this is for you."

This filters readers in (those who relate) and out (those who don't), respecting everyone's time.

2. Establish credibility early

Before diving into the problem, briefly establish why the author has authority:

  • Personal experience running CI at scale

  • Concrete numbers from real projects

  • Or frame it as "Here's what we learned building NixCI"

3. Deepen the stakes in the problem section

Current: "Real cost: context switching, lost flow state, compounding errors"

This is accurate but abstract. Make it visceral:

  • A specific story of a painful CI failure

  • Research on the cost of interruption (studies show 23 minutes to regain focus)

  • The compounding error problem with an example

4. Earn the Nix introduction

Currently, Nix appears as "the answer" without earning that position.

Structure instead:

  1. Show why Docker/CI config don't truly solve reproducibility

  2. Define what hermetic builds require

  3. Then introduce Nix as one tool that achieves this

This respects readers who might not choose Nix but still learn from the piece.

5. Signal commercial intent early (if applicable)

If NixCI is the product being promoted, be upfront:

"We built NixCI to solve this problem. Here's the philosophy behind it."

Readers respect transparency. They resent feeling tricked.

6. Add evidence to the workflow section

"Local CI in 2 min" — where does this number come from?

  • Actual benchmark from a real project

  • Comparison table with cloud CI times

  • Screenshot or log output

7. Strengthen the conclusion

Current: "AI will only get faster. Your feedback loop needs to keep up. Local-first CI closes the gap."

This is a truism, not a conclusion. Options:

  • End with a specific action: "Try nix flake check on your project today"

  • End with a memorable frame: "The fastest code is the code that never breaks CI"

  • End with a question that lingers: "How much time did you lose to CI this week?"

Refined Strategy for Nix-Curious Readers

Since readers are Nix-curious but not Nix users:

  1. Don't assume Nix knowledge — explain why Nix solves this, not just that it does

  2. Lower the barrier — one command (nix flake check) is the entire pitch

  3. Acknowledge the learning curve — don't pretend Nix is trivial to adopt

  4. Make the concept portable — even if they don't adopt Nix, they should remember "local-first CI"

Refined Strategy for Thought Leadership

Since this is thought leadership, not product marketing:

  1. The concept is the star — "local-first CI" should be memorable and shareable

  2. NixCI validates the philosophy — "We built NixCI on this principle" not "Use NixCI"

  3. Give readers something to take away — a framework, a mental model, a question to ask their team

  4. Be generous — help readers even if they never use your product

Revised Outline Structure

1. HOOK (keep - it's strong)
   "AI can write code in seconds. Your CI takes 20 minutes..."

2. THE HIDDEN TAX (expanded)
   - Concrete numbers: what 20-min CI actually costs
   - Research on context switching (cite the 23-minute refocus stat)
   - The compounding problem: first error breeds more errors
   - YOUR DATA: real before/after metrics

3. A DIFFERENT QUESTION
   - "What if CI could run locally, identically, every time?"
   - Not just tests — the full pipeline
   - The key property: local pass = remote pass

4. THE REPRODUCIBILITY GAP (earn the Nix introduction)
   - Why Docker doesn't fully solve this (env vars, timestamps, network)
   - What true hermetic builds require
   - "There's a tool that does this: Nix"
   - Brief, accessible explanation of Nix's guarantees

5. THE NEW LOOP
   - AI writes → local CI (2 min) → fix → push confident
   - YOUR DATA: specific example with real timings
   - The psychological difference: feedback while context is fresh

6. OBJECTIONS ADDRESSED
   - "But my builds are huge" → binary caching, distributed workers
   - "But I need cloud CI for PRs" → local-first ≠ local-only
   - "But Nix is hard" → acknowledge this honestly, point to resources

7. CONTROL YOUR INFRASTRUCTURE
   - Brief section on self-hosted benefits (not a sales pitch)
   - Workers behind NAT, no vendor lock-in, no surprise bills

8. CONCLUSION (strong CTA)
   - "How much time did you lose to CI this week?"
   - One action: try `nix flake check` on a project
   - Frame: "The fastest code is code that never breaks CI"

Key Edits to Make

  1. After hook: Add audience signal + credibility

  2. Problem section: Include your concrete metrics, cite research

  3. Reproducibility section: Earn Nix by showing why Docker falls short

  4. Workflow section: Replace hypothetical with real data

  5. Objections: Be honest about Nix's learning curve

  6. Conclusion: End with action and memorable frame, not truism