Explain Guided Build Lab without relying on framework buzzwords.
Connect the lesson to the phase outcome: Build a trustworthy GitHub Actions pipeline that verifies pull requests, creates immutable release artifacts, uses least privilege, caches safely, and controls deployment concurrency.
Reproduce the relevant behavior and verify it with evidence.
Diagnose at least one representative failure instead of guessing.
Figure 33.13 — TaskFlow boundary map
pull request
→
deterministic install
→
lint/typecheck/test/build
→
trusted main
→
immutable artifact
→
environment gate
→
deployment
This lesson belongs to Phase 33. Keep the full request/data path visible even when today's code changes only one box.
Instructor workflow: predict first → implement the smallest slice → run it → inspect evidence → break one assumption → diagnose → explain it back. Do not copy the whole code block before understanding the first failing boundary.
Guided Build Lab — Phase 33: CI/CD with GitHub Actions
Purpose
Build a trustworthy GitHub Actions pipeline that verifies pull requests, creates immutable release artifacts, uses least privilege, caches safely, and controls deployment concurrency.
Deliverable
.github/workflows/ci.yml plus release/deploy workflows that build once, tag by commit SHA, and gate promotion.
Before you touch the code
Open the previous phase checkpoint, run the repository's verification commands, and make sure Git is clean. A guided lab is useful only when you know which change introduced a failure. Write down the current browser/API/database behavior you expect before modifying anything.
Read this flow left to right, then right to left. For each arrow, say what data crosses the boundary, which side trusts the other, and what evidence would prove that this boundary works. This habit prevents framework APIs from becoming disconnected memorization.
Step 1 — Create CI triggered by pull_request with read-only contents permission and explicit concurrency cancellation.
Do the smallest version of this step first. After the change, stop and verify it before continuing. Use terminal output, HTTP responses, browser DevTools, tests, or database inspection depending on the boundary. If the result differs from your prediction, do not add more code; explain the mismatch and fix the earliest failing assumption.
Step 2 — Set up Node and pnpm, then install with --frozen-lockfile so manifests cannot drift from the lockfile.
Do the smallest version of this step first. After the change, stop and verify it before continuing. Use terminal output, HTTP responses, browser DevTools, tests, or database inspection depending on the boundary. If the result differs from your prediction, do not add more code; explain the mismatch and fix the earliest failing assumption.
Step 3 — Run lint/typecheck/tests/build as separate clear steps or jobs with understandable failure ownership.
Do the smallest version of this step first. After the change, stop and verify it before continuing. Use terminal output, HTTP responses, browser DevTools, tests, or database inspection depending on the boundary. If the result differs from your prediction, do not add more code; explain the mismatch and fix the earliest failing assumption.
Step 4 — Add dependency/package cache only after correctness works; key it from lockfile inputs.
Do the smallest version of this step first. After the change, stop and verify it before continuing. Use terminal output, HTTP responses, browser DevTools, tests, or database inspection depending on the boundary. If the result differs from your prediction, do not add more code; explain the mismatch and fix the earliest failing assumption.
Step 5 — Create trusted-main release workflow that tags an image/artifact with the commit SHA rather than latest only.
Do the smallest version of this step first. After the change, stop and verify it before continuing. Use terminal output, HTTP responses, browser DevTools, tests, or database inspection depending on the boundary. If the result differs from your prediction, do not add more code; explain the mismatch and fix the earliest failing assumption.
Step 6 — Add environment protection/permissions for deployment and ensure stale production runs are not silently canceled mid-release.
Do the smallest version of this step first. After the change, stop and verify it before continuing. Use terminal output, HTTP responses, browser DevTools, tests, or database inspection depending on the boundary. If the result differs from your prediction, do not add more code; explain the mismatch and fix the earliest failing assumption.
Checkpoint
When the lab works, inspect git diff. Remove accidental debugging output and unrelated edits. Run type checking/tests/build commands relevant to this phase. Commit the checkpoint with a message that describes the capability added, not merely the files changed.
Explain-back
Without looking at the lesson, explain why each layer in the architecture trace exists, what this phase added to TaskFlow, and what would break if the new responsibility were moved to the wrong layer. If you cannot explain the boundary, repeat the trace before moving on.
Executable lesson studio · ui
Now turn the explanation into engineering skill.
Guided Build Lab matters because it changes a real boundary in TaskFlow. The goal is to understand the inputs, owner, observable output, and failure modes before adding more abstraction.
By the end, you should be able to
Explain Guided Build Lab in terms of concrete inputs, ownership, outputs, and evidence.
Implement or reproduce the smallest TaskFlow slice that demonstrates this ui concept.
Diagnose one representative ui failure using observable evidence instead of trial-and-error.
Figure 33.13B — Mental model
route data
→
UI state
→
component tree
→
interaction
→
accessible feedback
Read left-to-right while implementing. When debugging, walk right-to-left until the first observed fact differs from your prediction.
Code-along sequence
One coherent change at a time
01
Restate the goal of “Guided Build Lab” as one observable behavior. Write the success signal before touching code.
02
Trace the boundary map: route data → UI state → component tree → interaction → accessible feedback. Mark the one boundary this lesson changes.
03
Inspect the current repository state and record the exact files, route, table, or runtime involved. Avoid creating an abstraction before you can name the existing owner.
04
Implement the smallest vertical slice. Add one coherent change, run the narrowest verification command, and read the output before continuing.
05
Connect the slice to TaskFlow’s phase artifact: .github/workflows/ci.yml plus release/deploy workflows that build once, tag by commit SHA, and gate promotion.. Verify behavior from the outside as a user or API client would.
06
Create one controlled failure that is safe to reproduce. Predict the symptom first, capture evidence, locate the earliest broken boundary, then fix only that cause.
07
Close the reference and rebuild or explain the core change from memory. Record what you would monitor or test before trusting the same change in production.
tsxModel non-happy states intentionally
if (query.isPending) return <TaskSkeleton />;
if (query.isError) return <TaskError retry={query.refetch} />;
if (!query.data.length) return <EmptyTasks />;
return <TaskTable tasks={query.data} />;
Do not copy this as a finished answer. Predict what each boundary does, type the smallest useful slice, run it, then compare the result with your prediction.
Verification
Prove the happy path
Run the narrowest relevant command or request and require a clean exit/status.
Inspect the boundary-specific evidence: terminal output, Network panel, database row/query plan, test report, container health, or deployment logs.
Repeat the behavior once after the change so a one-off cached or stale result cannot masquerade as success.
Break it on purpose
Build debugging memory
Using pull_request_target with untrusted checkout/secrets
Change one assumption in the ui example—identity, input, configuration, ordering, connectivity, or state—and predict the exact symptom before running it.
SymptomInvestigation path
Expected result does not appear
Return to the nearest observable boundary: input, network, process log, database, or rendered UI. Compare actual evidence with the predicted path.
A shortcut appears to fix it
Change one variable at a time and reproduce the original failure after the fix; otherwise you have correlation, not diagnosis.
Closed-reference challenge
Can you transfer the idea?
Without copying the final source, create a second small scenario that applies “Guided Build Lab” to a different TaskFlow resource or input. Write the acceptance criteria first, implement it, and provide the evidence that each criterion is satisfied.
Explain-back
Answer these without reopening the solution
What problem does Guided Build Lab solve in TaskFlow, and what would be observably wrong without it?
Which part of the ui boundary owns the decision, and which neighboring layer must not own it?
What evidence proves the happy path instead of merely suggesting it worked?
Name one realistic failure or abuse case and the first place you would inspect.
If requirements doubled tomorrow, which part of this design should stay stable and which part is allowed to change?
Lesson studio
Turn the reading into skill
01
Do it
Create CI triggered by pull_request with read-only contents permission and explicit concurrency cancellation.
Use the smallest change that demonstrates this lesson. Stop after it works and capture evidence.02
Break it safely
Using pull_request_target with untrusted checkout/secrets
Predict the symptom before causing the failure. Then locate the earliest boundary where reality diverges from expectation.03
Explain it back
Why does this responsibility live here, what input does it trust, what output proves success, and what would go wrong if another layer owned it?
If your explanation is vague, repeat the boundary trace before moving on.
Exit ticket
Before marking complete
Close the reference. Reproduce the core idea from memory or explain the exact request/data flow aloud. Then check your diff or notes for accidental shortcuts that bypass validation, authorization, error handling, or verification earned in earlier phases.