Feedback Loops

Problem: Claude ships a function, and then you babysit it. You copy the code, run it by hand, paste the error back, wait. That round trip is the loop you're trying to kill.

Quick Win: Hand off the whole cycle in one sentence:

claude "implement the validation function and run tests until they pass"

Claude writes the code, fires your test suite, reads the failures, fixes them, and spins the cycle again until everything is green. One prompt, the whole loop.

How It Works

Claude Code sits inside your terminal with everything your project already uses. The cycle is short and mechanical:

1. Write the code
2. Execute it, or kick off the tests
3. Read whatever the tools printed
4. Patch against what the output said
5. Loop back to step 1 until the work is green

Zero flags. Zero config. You just say the word "iterate" and it does.

Real Iteration Prompts

Run Until Tests Pass

claude "implement user authentication and run the tests until they all pass"

Claude writes the auth code, fires off your test command (usually npm test, whatever your project uses), reads the failures that come back, rewrites, and runs the whole thing again.

Fix Errors as They Appear

claude "start the dev server and fix any errors that come up"

Claude boots npm run dev, tails the log, and patches whatever breaks, whether it's a TypeScript complaint or a runtime throw.

Iterate on Specific Problems

# When you see an error, paste it
claude "this error appeared: [paste error]. fix it and run again"

The terminal output becomes the prompt, with no translation layer in between.

Using Your Actual Dev Tools

Whatever toolchain your repo runs on, Claude runs on too:

# Node.js projects
claude "run npm test and fix any failures"
 
# Python projects
claude "run pytest and fix the failing tests"
 
# With watch mode
claude "run the tests in watch mode and fix issues as they fail"

Test runner, dev server, linter, anything that prints to stdout. Claude reads the output and reacts in real time.

Structure Work for Fast Iteration

Big asks blur. Small asks validate:

# Instead of one massive request
claude "build the entire user system"
 
# Break into validatable chunks
claude "create the user model and write a test for it"
claude "add the registration endpoint and test it"
claude "implement login with the tests"

Every chunk carries its own finish line. Claude can tell when the chunk is done.

Error-Driven Development

Make the error the specification:

# Start with a failing test
claude "write a test for user registration that checks email validation"
 
# Then make it pass
claude "implement registration to make this test pass"

Now "done" is concrete. The failing test is the contract, and Claude codes toward a green bar.

Formalize the pattern and it scales. ClaudeFast's Code Kit splits the work across two agents: one specialist writes the feature, a separate quality-engineer agent grades the result against acceptance criteria. The loop runs itself before any human eyes land on the diff.

When Things Go Wrong

Claude keeps making the same mistake. Name the failure mode:

claude "the test still fails because X. try a different approach"

Infinite loop of fixes. Force a pause:

claude "stop and explain what's going wrong before trying another fix"

Claude can't see the error. Paste it in:

claude "here's the full error output: [paste]. fix this specific issue"

Next Steps

A good Claude Code session should run like pair programming: write, run, read the result, fix, go again.

• Set up permission management for smoother execution
• Learn git integration for version control
• Use todo workflows for complex projects
• Explore usage optimization to manage costs

Whoever owns the tightest loop wins the round. Tell Claude to iterate, and get out of its way.