Codex CLI Research

Field notes on Codex CLI, AGENTS.md, MCP permissions, review receipts, verification evidence, and production agent workflows.

Start with Codex CLI workflows, AI coding governance, and team conventions.

Birds and Flowers, landscape painting by Kano Shōei (1540).
Methodology·6 min read

How to set up an AI coding workshop for your engineering team

How to set up an AI coding workshop: pick a format, scope it to your real repos and review habits, run hands-on labs, and leave with a shared playbook.

June 7, 2026·Rogier Muller
Pond at Ville-d'Avray, landscape painting by Jean Baptiste Camille Corot (1865).
AI-Assisted Coding·8 min read

Codex CLI, Appshots, and Goal Mode

A practical Codex CLI comparison for codex cli vs claude code, with AGENTS.md, MCP, and verification loops.

May 24, 2026·Rogier Muller
Othon Friesz Port normand, landscape painting by Othon Friesz (1900).
AI-Assisted Coding·8 min read

MCP training for engineering teams

Practical mcp training for engineering teams using agentic coding, review guardrails, and connector boundaries.

May 21, 2026·Rogier Muller
Harbor of Boston, with the City in the Distance, landscape painting by Fitz Henry Lane (1846).
AI-Assisted Coding·8 min read

Codex CLI 0.132.0: workflows and integrations

Codex CLI 0.132.0 tightens AGENTS.md, MCP, and verification loops for reviewable diffs.

May 20, 2026·Rogier Muller
Phoenixes and Paulownia, landscape painting by Tosa Mitsuyoshi (1580).
AI-Assisted Coding·5 min read

Agentic Coding Breaks At The Handoff

Most teams do not lose control when an agent writes bad code. They lose it when nobody can explain the change ten minutes later. The handoff is the interface.

May 17, 2026·Rogier Muller
Peacocks and Bamboo, landscape painting by Tosa Mitsuyoshi (1580).
AI-Assisted Coding·6 min read

Codex governance: four contracts that hold in review

A codex governance note for engineering teams: the slash catalog, verification latch, browser bridge note, and model pin that keep Codex CLI work reviewable.

May 17, 2026·Rogier Muller
Landscape painting by Ralph Albert Blakelock, from the Catholina Lambert Collection catalogue (1916).
AI-Assisted Coding·5 min read

Best practices for agentic coding in real environments

An operating guide to best practices for agentic coding in real environments: rule-file precedence, scope ledgers, replay receipts, connector cards.

May 16, 2026·Rogier Muller
Landscape with Saint John the Baptist, landscape painting by Herri met de Bles (1535).
AI-Assisted Coding·6 min read

Codex mobile CLI: runs that survive review

A codex mobile cli pattern for running Codex CLI from anywhere: verification latches, model pins, and connector rosters that keep remote runs reviewable.

May 16, 2026·Rogier Muller
The ruins of the Khan's tomb and a small minaret in Bolgar, Shishkin (2022-12-06), landscape painting by Ivan Shishkin.
AI-Assisted Coding·5 min read

Why agentic coding governance beats raw speed

Agentic coding governance beats speed: connector cards, child receipts, decision stubs, and scope ledgers that make agent diffs defensible after merge.

May 15, 2026·Rogier Muller
Château des environs de Paris, landscape painting by Paul Cézanne (1888).
AI-Assisted Coding·5 min read

How to set up agentic coding workflows and guardrails

A field guide to agentic coding workflows and guardrails: handoff receipts, connector ownership, and review gates for engineering teams under deadline.

May 15, 2026·Rogier Muller
Autumn in the Mountains, landscape painting by Unknown (1600).
AI-Assisted Coding·5 min read

Codex workflows for mobile handoffs

Codex workflows for mobile handoffs: the repo contract of model pins, connector rosters, done checklists, and slash catalogs that lets agent work change hands.

May 15, 2026·Rogier Muller
View of a Lake, landscape painting by Thomas Doughty (1830).
AI-Assisted Coding·6 min read

Codex mobile CLI docs your team can read anywhere

The codex mobile cli question is a docs question: how a team keeps AGENTS.md rules, run notes, and verification transcripts readable away from the desk.

May 15, 2026·Rogier Muller
Scenes from the Tale of Genji, landscape painting by Tosa School (1700).
AI-Assisted Coding·5 min read

Codex workspace agents need repo rules

Codex workspace agents and Codex cloud agents need repo rules: scoped boundary files, connector cards, and replay receipts reviewers can check.

May 14, 2026·Rogier Muller
Twilight in the Wilderness, landscape painting by Frederic Edwin Church (1860).
AI-Assisted Coding·6 min read

Codex workflows: governance that lives in the repo

How to govern codex workflows from the repo: a connector roster, a ten-line done checklist, a slash catalog, and a verification latch reviewers can replay.

May 14, 2026·Rogier Muller
Die Gartenlaube (The Garden Arbor), landscape painting by Andreas Achenbach.
AI-Assisted Coding·5 min read

Fast mode is not the default: when fast models earn it

The fast model is a tradeoff you make on purpose: scope ledgers, replay sandwiches, and connector cards that keep fast agent runs reviewable.

May 13, 2026·Rogier Muller
Tartars Hunting in a Mountain Landscape, landscape painting by Unknown (1615).
AI-Assisted Coding·5 min read

Codex-auto-review: what it catches and misses

Codex-auto-review trials showed Codex catching syntax drift and missing permission drift. The fix is transcript evidence and repo contracts, not more autonomy.

May 13, 2026·Rogier Muller
Capri, landscape painting by Jean Achille Benouville (1840).
AI-Assisted Coding·5 min read

Is Codex CLI giving MCP more reach than reviewers expect?

An operational memo for Codex CLI 0.129.0: MCP boundaries, connector owners, allowed actions, AGENTS.md instructions, and reviewable diffs.

May 11, 2026·Rogier Muller
Landscape with a Castle, landscape painting by John Martin (1815).
AI-Assisted Coding·5 min read

AI agent guardrails that hold

A field guide to AI agent guardrails for recursive agent chains: connector ownership, child receipts, and review evidence that survives the merge queue.

May 10, 2026·Rogier Muller
The Kiss of Peace and Justice, landscape painting by Laurent de La Hyre (1654).
AI-Assisted Coding·5 min read

Codex workflows for Chrome and the CLI

Codex workflows that cross into Chrome: the browser bridge note, model pin, connector roster, and done checklist that keep two surfaces telling one story.

May 10, 2026·Rogier Muller
A Storm Behind the Isle of Wight, landscape painting by Julius Caesar Ibbetson (1790).
AI-Assisted Coding·6 min read

Agentic workflows from PR to merge

A PR review workflow for agentic coding teams: connector ownership, scoped tasks, replay transcripts, and human approval lanes from PR to merge.

May 9, 2026·Rogier Muller
Rocky, Wooded Landscape with a Dell and Weir, landscape painting by Thomas Gainsborough (1777).
AI-Assisted Coding·5 min read

Codex-cli 0.130.0: workflows that survive the update

What codex-cli 0.130.0 means for production repos: the AGENTS.md boundaries, MCP permissions, and review receipts that hold across any Codex CLI release.

May 9, 2026·Rogier Muller
Château de Pierrefonds restauré par Viollet-le-Duc, landscape painting by Paul Huet.
AI-Assisted Coding·5 min read

Agentic coding governance for engineering teams

Agentic coding governance for engineering teams: the written contracts, decision stubs, scope ledgers, and replay receipts, that keep agent diffs explainable.

May 7, 2026·Rogier Muller
The Waterfalls at Tivoli, landscape painting by Claude-Joseph Vernet (1737).
Open Source·5 min read

Codex CLI 0.121.0 for repo workflows

Codex CLI 0.121.0 repo workflows: named connector owners, a pinned model in AGENTS.md, and PR receipts that survive reviewer handoffs.

May 7, 2026·Rogier Muller
Landscape with Castle Ruins and Riders, landscape painting by Carl Friedrich Lessing (1878).
AI-Assisted Coding·6 min read

The AI code review workflow that survives green CI

An AI code review workflow for agentic teams: connector ownership, scoped fixes, decision stubs, and replay evidence that hold up when CI is green.

May 6, 2026·Rogier Muller
Montclair, New Jersey, landscape painting by George Inness (1873).
AI-Assisted Coding·6 min read

Codex CLI workspace tools that make runs reviewable

Codex CLI workspace tools that carry the operating contract: model pin, connector roster, done checklist, and slash catalog for reviewable agent runs.

May 6, 2026·Rogier Muller
Hunters Near Ruins, landscape painting by Jan Baptist Weenix (1648).
AI-Assisted Coding·6 min read

Agentic coding governance that holds in review

Agentic coding governance as an operating guide: connector ownership, scope ledgers, decision stubs, and review receipts for MCP-connected engineering teams.

May 5, 2026·Rogier Muller
The Old Bridge over Hook Pond, East Hampton, Long Island, New York, landscape painting by Thomas Moran (1907).
AI-Assisted Coding·5 min read

Codex CLI 0.122.0: workflows, permissions, MCP

A Codex CLI 0.122.0 workflow guide: AGENTS.md instructions, permission boundaries, MCP rosters, and verification reviewers can replay.

May 5, 2026·Rogier Muller
Panoramic View of the Alps, Les Dents du Midi, landscape painting by Gustave Courbet (1877).
AI-Assisted Coding·5 min read

AI agent guardrails: why every harness needs them

Why agent harnesses need guardrails: AI agent guardrails that turn complete-sounding summaries into receipts reviewers can actually verify.

May 4, 2026·Rogier Muller
The Large Plane Trees (Road Menders at Saint-Rémy), landscape painting by Vincent van Gogh (1889).
AI-Assisted Coding·5 min read

Codex CLI 0.123.0: workflows that hold up

Codex CLI 0.123.0 workflows that hold up in review: replay recipes in the diff, a pinned model, a connector roster, and a ten-line done checklist.

May 4, 2026·Rogier Muller
Castle on a River, landscape painting by Salomon van Ruysdael (1644).
AI-Assisted Coding·6 min read

AI coding agents need workflow guardrails

Workflow guardrails for AI coding agents: a precedence clause, a replay mandate, connector cards, and child receipts that keep forks explainable in review.

May 3, 2026·Rogier Muller
View of Saint-Cloud, Near the Seine, landscape painting by Alexandre Pau de St. Martin (1809).
AI-Assisted Coding·5 min read

Codex CLI 0.124.0: tighter rollback loops

Codex CLI 0.124.0 as a workflow moment: shrink the rollback contract, pin the model, and keep a connector roster and done checklist where reviewers live.

May 3, 2026·Rogier Muller
The Storm, landscape painting by George Inness (1876).
AI-Assisted Coding·6 min read

Always-on AI code review governance

AI code review governance for always-on agents: receipts, scopes, and owners that answer why a file changed without replaying chat.

May 2, 2026·Rogier Muller
Trouville, le port, landscape painting by Eugène Boudin (1885).
AI-Assisted Coding·5 min read

Codex 5.5: pin the model before you swap it

Codex 5.5 questions are model governance questions: pin the default model and escalation rule in AGENTS.md, and keep browser checks bridged to CLI receipts.

May 2, 2026·Rogier Muller
Studies of Jacky Turner and the Reverend Charles Hope's Gardener, landscape painting by James Ward (1800).
Methodology·6 min read

AI agent boundaries that hold under pressure

A boundary-setting guide to AI agent boundaries: connector cards, scope ledgers, child receipts, and decision stubs that stop permission drift.

May 1, 2026·Rogier Muller
Landscape, landscape painting by Kano Motonobu (1525).
AI-Assisted Coding·6 min read

Codex CLI /goal workflows with AGENTS.md

A practical Codex CLI /goal workflow guide: persistent goals carry intent, AGENTS.md carries boundaries, and receipts carry proof across handoffs.

May 1, 2026·Rogier Muller
Villa in Dresden, landscape painting by Ernst Ludwig Kirchner (1910).
Methodology·6 min read

Eval platform governance for AI coding teams

A governance memo on eval platform governance: receipts behind scores, scoped harness access, and owners that stop Goodhart drift.

April 29, 2026·Rogier Muller
Cliffs by the Coast of Northern Norway, landscape painting by Peder Balke (1840).
AI-Assisted Coding·5 min read

codex-cli 0.125.0: reviewable agent loops

An operational memo for codex-cli 0.125.0: reviewable agent loops, AGENTS.md pins, verification transcripts, and connector rosters.

April 29, 2026·Rogier Muller
Summer and Winter Landscapes (one of a pair), landscape painting by Kano Naonobu (1607).
Methodology·6 min read

Agent boundaries for teams running coding agents

How to set agent boundaries for teams: connector ownership, written scopes, and review receipts that keep agent diffs explainable after the session ends.

April 28, 2026·Rogier Muller