blumeops/docs/how-to/agent-change-process.md
Erich Blume 66b5b32f1d Formalize C0/C1/C2 change classification (#259)
## Summary
- **C0 (Quick Fix):** Now explicitly allows direct-to-main commits with no PR required — for low-risk, fix-forward-safe changes
- **C1 (Human Review):** New docs-first workflow with branch deployment (ArgoCD `--revision`, Ansible from checkout). Includes upgrade criteria for escalation to C2
- **C2 (Mikado Chain):** Introduces the **Mikado Branch Invariant** — strict commit ordering where card-introducing commits come first, followed by code progress, followed by card closures. Branch resets required when new prerequisites are discovered

Updates CLAUDE.md rules (3, 4, 8, 9) to reflect that C0 bypasses branching/PR requirements. Also updates ai-assistance-guide, how-to index, and docs-mikado task description.

## Files changed
- `CLAUDE.md` — rules and classification table
- `docs/how-to/agent-change-process.md` — full process rewrite
- `docs/tutorials/ai-assistance-guide.md` — branching and pitfalls sections
- `docs/how-to/how-to.md` — index description
- `mise-tasks/docs-mikado` — task description
- `docs/changelog.d/formalize-change-classification.doc.md` — changelog fragment

Reviewed-on: https://forge.ops.eblu.me/eblume/blumeops/pulls/259
2026-02-23 16:19:54 -08:00

13 KiB

title modified last-reviewed tags
Agent Change Process 2026-02-23 2026-02-23
how-to
ai

Agent Change Process

How to classify and execute infrastructure changes, especially when working with AI agents that may lose context across sessions.

Change Classification

Before starting work, classify the change:

Class Name When to use Key trait
C0 Quick Fix Small, low-risk, fix-forward safe Direct to main, no PR
C1 Human Review Moderate complexity or risk Feature branch + PR, docs-first
C2 Mikado Chain Multi-phase, multi-session, high complexity Mikado Branch Invariant

When in doubt, start at C1. Upgrade to C2 if complexity spirals or the user requests it.

C0 — Quick Fix

A change where the risk is low enough that problems can be quickly fixed forward.

  1. Run mise run ai-docs to load context
  2. Implement the change directly on main
  3. Commit and push

No feature branch or PR required. If something goes wrong, fix forward with another commit.

Examples: fix a typo, bump a version, add a simple config value, update a doc.

C1 — Human Review

A change with enough complexity or risk that a human should review it, but not so much that a formal multi-phase approach is needed.

Process

  1. Run mise run ai-docs to load context
  2. Search related docs — read existing documentation and reference cards related to the change area
  3. Create a feature branch and open a PR early (draft is fine)
  4. Documentation first — commit doc changes reflecting the desired end state before writing code. This helps the reviewer understand intent and catches design issues early
  5. Implement — commit code changes, pushing as you go. The PR gets updated along the way and the user can review and comment at any point
  6. Deploy from the branch — do not wait for merge:
    • ArgoCD: argocd app set <service> --revision <branch> && argocd app sync <service>
    • Ansible: run playbooks directly from the branch checkout
    • Workflows: point workflow triggers at the branch if needed
  7. After user review and successful deployment, the user merges the PR
  8. After merge: reset ArgoCD revisions back to main, re-sync

Upgrading to C2

Upgrade to C2 if any of these happen during a C1 change:

  • You discover the change requires multiple prerequisite changes that must be sequenced
  • The change is spiraling in complexity beyond a single session
  • The user requests it
  • During planning you realize this is a multi-phase project

C2 — Mikado Chain

A complex, multi-session change managed through the Mikado method with a strict branch discipline called the Mikado Branch Invariant.

Planning and research

Before writing any code, invest in understanding the problem:

  1. Run mise run ai-docs to load context
  2. Search related docs, reference cards, and existing how-to guides for the change area
  3. Think through the dependency graph — what prerequisites exist? What could go wrong?
  4. Create Mikado cards for everything you can anticipate (you'll discover more later — that's the point of the method)

This planning phase can span multiple sessions. Cards introduced during planning are merged to main and become the foundation for work cycles later.

The Mikado Branch Invariant

The invariant governs how commits are ordered on a C2 feature branch. The branch must always have this structure:

main ← [plan commits] ← [impl, close] ← [impl, close] ← ... ← [finalize]
       ^^^^^^^^^^^^^^^^  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
       Planning layer    Repeating work cycles
       (cards only)      (impl then close, one leaf at a time)

Rules:

  1. The first N commits on the branch (after diverging from main) must ALL be commits that only introduce or modify Mikado cards — no code changes
  2. After the card layer, work proceeds in cycles: each cycle is one or more code commits followed by one or more commits closing leaf nodes
  3. A cycle should target a single leaf node (though closing multiple in one cycle is acceptable if the code supports it)
  4. Cycles repeat until the chain is complete

The one rule: No Mikado card may be introduced after any code or card-closing commit. New cards require a branch reset (see below).

The length-zero case: It is valid for the "planning layer" to have zero commits on the branch — this happens when all Mikado cards were introduced in earlier sessions and are already in main's history. The invariant is satisfied.

Exception — finalize: The terminal commit of a completed chain rewrites Mikado cards to historical documentation. This is a card modification after code commits, and is the only permitted violation of the one rule (see "Completing a chain" below).

Conventions

Branch naming

C2 branches must be named mikado/<chain-stem>, where <chain-stem> is the filename stem of the goal card. Example: goal card deploy-authentik.md → branch mikado/deploy-authentik.

Goal card branch: frontmatter

The goal card of a C2 chain must include a branch: field once work begins:

---
title: Deploy Authentik
status: active
branch: mikado/deploy-authentik
requires:
  - configure-postgres
  - setup-redis
tags:
  - how-to
---

A goal card with status: active but no branch: field indicates a chain that has been planned but not yet started — the planning-phase cards exist but no implementation branch has been created.

Commit message convention

All commits on a mikado/* branch must use this format:

C2(<chain-stem>): <verb> <short description>

Verbs and their meanings:

Verb Phase What it means
plan Planning layer Introduces or modifies a Mikado card (no code changes)
impl Work cycle Code progress toward closing a leaf node (no card changes)
close Work cycle Closes a leaf node by removing status: active
finalize Terminal Rewrites cards to historical docs, adds changelog

Examples:

C2(deploy-authentik): plan add postgres and redis prerequisite cards
C2(deploy-authentik): impl configure external-secrets for authentik
C2(deploy-authentik): close configure-postgres
C2(deploy-authentik): finalize rewrite cards as historical documentation

The mikado-branch-invariant-check commit-msg hook validates this convention and the invariant ordering.

Process

  1. Goal card: Create a how-to doc in docs/how-to/ describing the desired end state
    • Add status: active and branch: mikado/<chain-stem> to frontmatter
    • Create prerequisite cards discovered during planning, each with status: active
    • Commit all cards together (or in a sequence of card-only commits) using C2(<chain>): plan ... messages
  2. Open a PR after the first card commits so the user can review the Mikado graph
  3. Work leaf nodes — pick a leaf (a card with status: active and no unmet requires):
    • Commit code changes (C2(<chain>): impl ...) that progress toward closing it
    • Verify the change works (deploy from branch, run tests, etc.) before closing
    • Commit the card closure (C2(<chain>): close ...) — remove status: active
    • Push to origin — this is the save point
  4. Repeat until the chain is complete
  5. New agent sessions pick up state by running mise run docs-mikado --resume

Discovering new prerequisites

When you discover a new prerequisite during code work, you must restore the Mikado Branch Invariant:

  1. Reset the branch back to the top of the Mikado commit stack — the last C2(<chain>): plan or C2(<chain>): close commit before your current impl commits
  2. Add a new commit (C2(<chain>): plan ...) introducing the new prerequisite card (and updating requires on existing cards if needed)
  3. Replay the Mikado process from the new state of the card stack

Saving work across resets: It is acceptable to cherry-pick or rebase code commits from before the reset back onto the branch after adding the new card. This is a pragmatic exception — use it only when you are confident the saved work is still valid given the new prerequisite. When in doubt, redo the work from scratch.

Completing a chain

When the final leaf node is closed and no status: active cards remain:

  1. Rewrite all Mikado cards to reflect their nature as historical documentation:
    • Remove transient technical details (specific version numbers, temporary workarounds) that won't matter in the future
    • Frame the content as "what to do if someone wanted to repeat this process"
    • Add appropriate context about what was learned
    • Remove branch: from the goal card frontmatter
  2. Add changelog information in docs/changelog.d/
  3. Commit as C2(<chain>): finalize ... — this is the one permitted exception to the invariant's "no card changes after code" rule
  4. The user reviews and merges the PR

Cold-start: resuming a chain in a new session

When starting a new session to continue C2 work:

  1. Run mise run ai-docs to load context
  2. Run mise run docs-mikado --resume — this will:
    • Detect the current branch and match it to an active chain
    • Show the chain state, ready leaf nodes, and current position in the invariant
    • If on main, list active chains and suggest which to resume
  3. Check PR comments with mise run pr-comments <pr_number>
  4. Pick the next ready leaf node and continue with a work cycle

Build artifacts

Mikado resets apply to branch code, not build artifacts. Container images in the registry are independent of branch lifecycle:

  • Registry images are build outputs cached in zot — tagged with commit SHAs, so each build is unique and traceable
  • Automatic builds trigger when container changes merge to main. Use mise run container-build-and-release for manual dispatch
  • If a build succeeds but deployment fails, the image is fine; the problem is elsewhere. Document what you learned and try again
  • If a build fails in CI, no image is pushed. Fix the nix/dockerfile and re-merge or re-dispatch

Card Conventions

Frontmatter

---
title: Deploy Authentik
status: active          # omit when complete
branch: mikado/deploy-authentik  # goal cards only; omit when complete
requires:               # explicit dependencies
  - configure-postgres
  - setup-redis
tags:
  - how-to
---
  • status: active marks in-progress work; remove when done (this is the ONLY way a card is marked complete)
  • branch is set on goal cards only, linking the card to its mikado/<chain-stem> branch. A goal card with status: active but no branch indicates a chain that is planned but not yet started. Remove branch when the chain is finalized.
  • requires lists card stems (filenames without .md) that must be completed first. Keep requires permanently even after prerequisites are done — it documents the dependency graph history
  • required-by is NOT stored — it's computed by docs-mikado

Writing Cards

  • Mikado cards are not plans. Plans are designed upfront; Mikado cards are discovered through failed attempts. Don't put Mikado prerequisite cards in docs/how-to/plans/.
  • Cards live in a topic subdirectory under docs/how-to/ (e.g., docs/how-to/authentik/ for the deploy-authentik chain). The goal card may live in plans/ if it started as a plan.
  • Keep cards brief (<30 seconds to read)
  • Link to other cards rather than inlining their content
  • Document what was learned from failures, not just what to do

Git Discipline

  • C0: Commit directly to main
  • C1: Single feature branch, PR early, push often
  • C2: Branch named mikado/<chain-stem>, Mikado Branch Invariant enforced, C2() commit convention, PR early, push after every leaf-node closure
  • Deploy from branches — C1 and C2 changes deploy from the unmerged branch (ArgoCD --revision, Ansible from checkout, etc.). Reset to main after merge.
  • GitOps requires pushing to test — if a pushed commit breaks, revert it promptly

Tools

Command Purpose
mise run docs-mikado List all active Mikado chains with branch status
mise run docs-mikado <card> Show dependency chain for a goal card
mise run docs-mikado <card> --all Include completed cards in full
mise run docs-mikado --resume Resume a chain: detect branch, show state and next steps
mise run docs-mikado --resume <chain> Resume a specific chain with branch consistency check

The mikado-branch-invariant-check commit-msg hook runs automatically on mikado/* branches, validating commit message conventions and invariant ordering. Requires uvx pre-commit install --hook-type commit-msg.