Skills

Agentic TDD

Test-driven development for behaviour a unit test cannot reach, by writing the...

Install

npx skills add reticlehq/reticle --skill agentic-tdd -g -a claude-code -y
Repository
reticlehq/reticle1.3k
Category
Design
Updated
3d ago
License
Apache-2.0
Context cost
Lightabout 1,148 tokens
Runs scripts
No, instructions only

What it does

Test-driven development for behaviour a unit test cannot reach, by writing the expectation against the running app before writing the code. Declare the consequence first, watch it fail, implement, watch it pass. Use when building a user-facing feature, when the user asks for TDD on UI or full-stack work, when a unit test cannot express the outcome that matters, or when you want a red-green loop that runs against the real app instead of mocks.

Red, green, refactor: against the running app

Unit tests drive the units. They cannot say "clicking Deploy posts to /api/deploy, moves the store to deploying, and shows the banner": that outcome only exists when the whole app runs. So the loop stalls exactly where the interesting bugs are, and the agent falls back to writing code and hoping.

This runs the same discipline one level up, using Reticle to drive the real app. Not set up? Follow the reticle skill: it installs Reticle, asks the user before init changes the app's files, and proves one flow.

Why this is TDD and not just testing afterwards

The whole value of test-first is that the oracle is written while you still do not know the answer. An expectation written after seeing the result can always be adjusted into agreeing with whatever happened, and an agent is especially good at that adjustment. It will find a reading of the output under which the code it just wrote is correct.

reticle_act_and_wait({ ref, action, until }) enforces the order structurally: until is an argument to the action, so the consequence is named before the action runs. That is the red-green loop, made unfakeable.

1. RED: write the expectation, watch it fail

Before you write the feature, state what the app must do:

reticle_act_and_wait({ sessionId, ref, action: "click", until: { kind: "allOf", predicates: [
  { kind: "net",     method: "POST", urlContains: "/api/deploy", status: 200 },
  { kind: "signal",  name: "deploy:started" },
  { kind: "element", query: { testid: "deploy-banner" } },
  { kind: "console", level: "error", absent: true },
]}})

You want verified: "no" here. A red you did not see is a test you cannot trust. If this comes back yes before you have written anything, the expectation is not specific enough to the change. Tighten it until it fails for the right reason.

Read the whole SKILL.md on GitHub

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