Build a Claude Code Verification Harness
Claude Code writes code that looks right. In one hour we build the harness engineering pattern that makes it prove the code works before you review it. We build static analysis gates, holdout tests the implementing agent never sees, and a Doer and Tester loop that sends failures back with the reason attached. It carries over to Codex and Cursor with small changes to each tool's hook setup.
The lessons, in order
Each lesson is one idea from the live build, cut to a few minutes, with chapters and the full transcript.
- 15:11
Six Layers of a Software Factory
Boundary, context, skills, execution, verification and delivery: the six layers that turn a coding agent from a prompt you babysit into a process that ships.
- 2Out
CLAUDE.md Is Guidance, Not Verification
Not everything should be automated. Map each pull request to a lane, then see why CLAUDE.md only guides and what actually verifies the work: rules, gates and hooks.
- 3Out
Why Claude Code Cannot Grade Itself
An agent that writes the code and the test grades itself. A small TypeScript cart repo shows the fix: holdout tests the agent never sees.
- 4Out
Rules Ask, Gates Check
A rule in CLAUDE.md is an ask. A gate is deterministic and runs every time with no model. Here is the difference, and how a gate differs from a test.
- 5Out
Deny Rules and Hooks That Refuse
Deny rules keep the agent out of secrets and holdout tests, and a PreToolUse hook refuses every route around them.
- 6Out
The Stop Hook Closes the Loop
The agent says done. The Stop hook runs the gates, and red work goes back with the reason until it is green or a human steps in.
- 7Out
Will This Process Outlast the Next Model?
Fourteen years of shipping software says the engineering process barely changes. What the agent era changes, and what it does not.
What the course covers
Engineers who review agent pull requests that look right and break later, and the leads who set the bar for merging them.
- Add static analysis gates
- Reject code automatically before it merges or deploys, when it breaks your engineering rules.
- Write holdout tests
- Check behaviour with tests the implementing agent cannot see or tune itself against.
- Build a Doer and Tester loop
- Send failed work back to the agent with the reason until it passes or escalates.
- Wire the verification harness
- Connect gates, holdout tests and the Doer and Tester loop into one run that passes or fails.
More free mini courses
Every Lightning session becomes one, in the order the Software Factory gets built.