EvanFlow TDD Loop

---
name: evanflow-tdd-loop
description: Use EvanFlow's 16-skill TDD-driven iterative feedback loop for Claude Code to walk ideas from brainstorm through implementation with checkpoints and guardrails.
triggers:
  - "let's evanflow this"
  - "set up evanflow for my project"
  - "use evanflow to build this feature"
  - "run the evanflow loop"
  - "install evanflow skills"
  - "evanflow brainstorm plan execute"
  - "tdd feedback loop with claude code"
  - "evanflow coder overseer parallel"
---

# EvanFlow TDD Loop

> Skill by [ara.so](https://ara.so) — Daily 2026 Skills collection.

EvanFlow is a TDD-driven iterative feedback loop for software development with Claude Code. 16 cohesive skills + 2 custom subagents walk an idea from brainstorm → plan → execute → iterate, with real checkpoints where you stay in control. The agent never auto-commits, never auto-stages, never proposes a PR without your explicit direction.

brainstorm → plan → execute (vertical-slice TDD per task) → iterate → STOP └─ sequential, or parallel coder/overseer

---

## Installation

### Path 1 — Plugin Marketplace (recommended)

Auto-wires all skills, subagents, and the guardrail hook:

/plugin marketplace add evanklem/evanflow /plugin install evanflow@evanflow

Restart Claude Code (or `/reload-plugins`). Skills appear as `/evanflow:evanflow-go`, `/evanflow:evanflow-tdd`, etc.

To uninstall: `/plugin uninstall evanflow@evanflow`

### Path 2 — npx CLI (skills only)

```bash
# All 16 skills at once
npx skills@latest add evanklem/evanflow -s '*' -y

# Individual skills
npx skills@latest add evanklem/evanflow/evanflow-go
npx skills@latest add evanklem/evanflow/evanflow-tdd
npx skills@latest add evanklem/evanflow/evanflow-iterate

⚠️ This path does NOT install the guardrail hook or custom subagents. Add those manually if needed.

Path 3 — Manual Copy

git clone https://github.com/evanklem/evanflow.git
cd evanflow

# Skills (project-level)
mkdir -p .claude/skills
cp -r skills/* .claude/skills/

# Custom subagents
mkdir -p .claude/agents
cp agents/*.md .claude/agents/

# Git guardrail hook
mkdir -p .claude/hooks
cp hooks/block-dangerous-git.sh .claude/hooks/
chmod +x .claude/hooks/block-dangerous-git.sh

Register the hook in .claude/settings.json:

{
  "hooks": {
    "PreToolUse": [
      {
        "matcher": "Bash",
        "hooks": [
          {
            "type": "command",
            "command": "\"$CLAUDE_PROJECT_DIR\"/.claude/hooks/block-dangerous-git.sh"
          }
        ]
      }
    ]
  }
}

Requirements

• Claude Code (any recent version)
• Bash (Linux, macOS, or Windows + WSL)
• jq — used by the guardrail hook. Install via:

  # macOS
  brew install jq
  # Ubuntu/Debian
  apt install jq
  

  ⚠️ If jq is missing, the hook fails silently and dangerous git ops are NOT blocked.

• chromium or google-chrome (optional) — for UI screenshot verification in evanflow-iterate. Falls back gracefully if missing.

Verify Install

Restart Claude Code, then say:

"Let's evanflow this — I want to add a small feature that does X."

evanflow-go should fire and walk you through the loop.

---

The 16 Skills at a Glance

Default Loop (invoke in order, or via evanflow-go)

Skill	What it does
evanflow-brainstorming	Clarifies intent, proposes 2–3 approaches with embedded stress-test. Mockup quick-mode for visual-only requests.
evanflow-writing-plans	Maps file structure first, creates bite-sized tasks, offers parallel path if 3+ independent units.
evanflow-executing-plans	Runs tasks sequentially with inline verification. Surfaces blockers. Hands off to iterate, then STOPS.
evanflow-tdd	Vertical-slice TDD inside each code task: one failing test → minimal impl → refactor → next test.
evanflow-iterate	Self-review after implementation. Re-reads diff, runs quality checks, screenshots UI, Five Failure Modes checklist. Hard cap: 5 iterations.

Single Entry Point

evanflow-go   →   Say "let's evanflow this" — orchestrates the full loop.

Special-Purpose Skills

Skill	When to use it
evanflow-glossary	Extract canonical domain terms into CONTEXT.md
evanflow-improve-architecture	Surface refactor opportunities (deletion test + deep-modules)
evanflow-design-interface	"Design it twice" — 3+ parallel sub-agents with different constraints
evanflow-debug	Root-cause first, hypothesis stated explicitly, failing test before fix
evanflow-review	Both sides of code review; don't capitulate to feedback you can't justify
evanflow-prd	Synthesize a PRD from existing context
evanflow-qa	Conversational bug discovery → issue draft (asks before filing)
evanflow-compact	Long-session context management; triggers at clean phase boundaries

Custom Subagents (in agents/)

Subagent	Tool access	Role
evanflow-coder	Read, Edit, Write, Glob, Grep, Bash, TodoWrite	Implementation — no git ops, no out-of-scope edits
evanflow-overseer	Read, Grep, Glob only	Read-only review — physically cannot modify code

---

Key Workflows

1. Full Loop via Single Entry Point

User: "Let's evanflow this — add rate limiting to our API"

evanflow-go fires and sequences:

1. Brainstorm — proposes 2–3 approaches, stress-tests each, awaits your design approval
2. Plan — maps files first, creates tasks, offers parallel path → awaits your plan approval
3. Execute — runs tasks with TDD inside each code task → surfaces any blockers → hands to iterate
4. Iterate — self-review loop (max 5), Five Failure Modes check, quality checks
5. STOP — reports outcome, awaits your direction. No commits.

2. TDD Discipline Inside Execute

evanflow-tdd is the discipline inside every code-writing task — not a separate phase:

Per task:
  RED:    Write one failing test that specifies behavior via public interface
  GREEN:  Write minimal implementation to pass it
  REFACTOR: Clean up while the test is still your safety net
  → next test

Assertion-correctness check: would a one-character bug in the impl still pass this assertion? If yes, the assertion is wrong.

3. Parallel Coder/Overseer (3+ independent units)

When evanflow-writing-plans detects 3+ truly independent units, it offers the parallel path:

Plan with 3 independent modules
→ fork: 3 evanflow-coder subagents (one per module)
       + 3 evanflow-overseer subagents (one per coder, read-only)
       + 1 integration overseer (runs named integration tests at every touchpoint)

Integration tests are the executable contract — interfaces can't drift if both sides must satisfy the same passing test.

4. Architecture Review

User: "evanflow improve architecture on the auth module"

evanflow-improve-architecture runs the deletion test (if you deleted this, what breaks?) and deep-modules vocabulary (wide interface, narrow implementation) to surface refactor opportunities.

5. Debug with Root-Cause Discipline

User: "evanflow debug — users are getting 500s on /api/checkout"

evanflow-debug sequence:

1. State explicit hypothesis before touching code
2. Embedded stress-test of the hypothesis
3. Write a failing test that reproduces the bug
4. Fix → verify test passes → run full suite

6. Context Management for Long Sessions

User: "evanflow compact — we've been going for a while"

evanflow-compact triggers proactive summarization. Drift symptoms it watches for:

• Re-asking questions that were already settled
• Contradicting earlier decisions
• Losing track of which tasks are done vs. pending

---

Hard Rules (Every Skill Enforces These)

1. Never auto-commit, never auto-stage, never auto-finish. Every git write op requires your explicit ask in the current turn.
2. Never invent values. File paths, env vars, IDs, function names, library APIs — if unsure, the agent stops and asks.
3. No skill tax. Ad-hoc questions don't require a skill invocation.
4. No forced spec/plan paths. Files live where you want them.
5. Verify before claiming done. Typecheck, lint, and tests run before any "done" report.

---

Guardrail Hook — What It Blocks

hooks/block-dangerous-git.sh (PreToolUse on Bash) blocks:

git push            # blocked
git reset --hard    # blocked
git clean -f        # blocked
git branch -D       # blocked
git checkout .      # blocked
git restore .       # blocked

Safe git ops (status, diff, log, add, commit with your explicit instruction) pass through.

Test it: try git reset --hard HEAD via the Bash tool — it should be blocked with an explanation.

---

Skill Namespace After Plugin Install

After /plugin install evanflow@evanflow, skills are namespaced:

/evanflow:evanflow-go
/evanflow:evanflow-brainstorming
/evanflow:evanflow-writing-plans
/evanflow:evanflow-executing-plans
/evanflow:evanflow-tdd
/evanflow:evanflow-iterate
/evanflow:evanflow-debug
/evanflow:evanflow-review
/evanflow:evanflow-compact
/evanflow:evanflow-glossary
/evanflow:evanflow-improve-architecture
/evanflow:evanflow-design-interface
/evanflow:evanflow-prd
/evanflow:evanflow-qa
/evanflow:evanflow

Auto-invocation via natural language ("let's evanflow this") still works regardless of namespace.

---

Adding EvanFlow Context to Your Project

Paste the snippet from examples/CLAUDE.md.snippet into your project's CLAUDE.md to brief Claude about EvanFlow conventions from session start:

cat examples/CLAUDE.md.snippet >> CLAUDE.md

This ensures EvanFlow's vocabulary (deletion test, vertical-slice TDD, Five Failure Modes, etc.) is in context without requiring you to explain it each session.

---

Common Patterns

Starting a Feature from Scratch

"Let's evanflow this — I want to add webhook support to our API"

Jumping to a Specific Phase

"evanflow-plan: we've already brainstormed, here's the design we settled on: [...]"
"evanflow-tdd: implement the UserRepository.findByEmail method"
"evanflow-debug: the payment webhook is firing twice"

Using Design Interface for Hard API Decisions

"evanflow design interface for the plugin system — I want 3+ radically different approaches compared"

Running QA Conversationally

"evanflow qa — let's find bugs in the checkout flow before the release"

---

Troubleshooting

Problem	Fix
Hook not blocking dangerous git ops	Check jq is installed (jq --version). Check hook is executable (chmod +x .claude/hooks/block-dangerous-git.sh). Check settings.json registration (Path 3).
Skills not appearing after install	Restart Claude Code or run /reload-plugins. For manual install, verify files landed in .claude/skills/.
evanflow-go not triggering on "let's evanflow this"	Check skill is installed. Try explicit invocation: /evanflow:evanflow-go or /evanflow-go.
Chromium screenshot step skipped	Install chromium or google-chrome. evanflow-iterate falls back gracefully — it will flag UI changes need manual verification.
Parallel path not offered	Plan needs 3+ truly independent units. If tasks share state or ordering constraints, the sequential path is correct.
Agent inventing file paths / env var names	This violates Hard Rule 2. Tell the agent to stop and ask. If it persists, report as a bug at evanklem/evanflow.

---

Research Grounding

EvanFlow's hard rules cite their sources:

• Never invent values — action-hallucination is the #1 failure mode per DAPLab/Columbia "9 Critical Failure Patterns of Coding Agents"
• Assertion-correctness warning — 62%+ of LLM-generated test assertions were incorrect per "Test-Driven Development for Code Generation" (arXiv 2402.13521) §3.2
• Context drift watch — ~65% of enterprise AI failures in 2025 attributed to context drift, not raw context exhaustion per Alex Merced, "Context Management Strategies for OpenCode" (March 2026)

Rules without citations (no auto-commit, no skill tax) are labeled as opinion from running the loop on real projects.