In 20 to 30 minutes, a good recorded tour covers 8 chapters in my working order, from where a request enters the app to the decisions nobody would guess. That is the practical answer to “what is a codebase walkthrough?”: a guided tour of the repository, the data model and the key architectural decisions, recorded with chapter markers so the next engineer does not rediscover the system from scratch.
What is a codebase walkthrough, and how it differs from documentation and a handover call
A codebase walkthrough is a guided tour of one software project, given by someone who knows it to someone who does not. It shows 4 things: where the code is organized, how a request moves through it, where the data lives, and why the unusual decisions were made. Recorded, it serves engineers who have not been hired yet.
A codebase (also written “code base”: same word) is the full set of source files, configuration and scripts that build one product, usually kept in one repository. Files alone do not say which of them matter or why the odd ones look the way they do, and that is the gap the tour fills. Written reference is a different job, covered in documentation for a vibe-coded app: setup steps, settings, runbooks, decisions on paper.
The tour sits beside three other handover artifacts. The last column is my reading of how long each one stays accurate.
| Artifact | What it is | The question it answers | How long it stays true |
|---|---|---|---|
| Written documentation | Reference pages in the repository | ”What is the setting called?” | Goes stale file by file, as the code changes under it |
| Architecture diagram | One picture of the parts and how they connect | ”What talks to what?” | Until a component is added, removed or moved |
| Live handover session | A meeting with questions, held once | ”Can I ask you about this?” | As long as the people in the room remember it |
| Recorded walkthrough | A narrated screen recording of the code and the running app | ”Show me” | Until the parts it shows change, and an engineer hired a year later can still replay it |
Knowing how to create an architecture diagram is a separate skill from recording a tour, and so is knowing how to run a technical handover session. I’d record the tour rather than rely on the call, because in my reading the person who needs it most has not been hired yet. The tour is one of the engineering standards for AI-assisted teams that keep a codebase ready to change hands.
A code walkthrough in the review sense is a different thing
In software review practice, a code walkthrough means something else. Lecture slides from a project management course at California State University, Sacramento (CSc 233) define it as “a form of peer review where the author leads members of the development team and other interested parties through a software product and the participants ask questions and make comments about defects.” The same slides set it apart from an inspection, “a very formal type of peer review where the reviewers are following a well-defined process to find defects.” That kind of walkthrough hunts for defects in a piece of work; a codebase walkthrough explains a whole system to someone new. If peer review is what you came for, start from a code review checklist.
What goes wrong without it
These are the four ways I’d expect a handover without a tour to fail. How each one fails is my reading, not a measured rate.
| What was handed over | What the next engineer does first | What it costs the client |
|---|---|---|
| The repository and a README | Hunts for the entry points, the environment variables and the one folder that matters | Paid days of rediscovery before the first real change |
| A live call nobody recorded | Asks the same questions again, if the person who answered is still there | The knowledge sits in two heads, and both can leave |
| A ninety-minute unedited screen share | Scrubs back and forth looking for the part about payments | A recording that is technically a walkthrough and never watched twice |
| A recording in the agency’s own video account | Clicks the link in the README and gets an error | The tour disappears with the subscription or the employee |
The third row is an illustration, not a case I am reporting. When the first row is what you inherited, the first month of work is a legacy code takeover. Written setup steps also drift away from the code: in one app I audited, an ops SaaS, the setup instructions listed a required setting the code never read. The lesson I take from it: when the second chapter names each setting and opens the file where the code reads it, a listed setting that nothing reads has no file to point to, and the drift shows on screen.
Apps an AI builder generated add a fifth failure. Nobody on the team typed most of the code, so nobody can say from memory why a folder exists or which file holds a feature, and the tour is the first time the structure is said out loud. Preparing it is how the agency finds out what it does not know.
For context on code health in general: across the third-party apps from my June and July 2026 audits, the Maintainability and Evolvability pillar averages 61.1 out of 100, scored on 21 of the 21 apps (pillars marked N/A were excluded, not zeroed), and it ranks 10th of 12 pillars, counting from the weakest. Those 21 apps are a selected set I audited, not a random sample and not a rate for AI-built apps in general, and the pillar score says nothing specific about tours. In my reading, most handovers skip the tour because nobody asked for one.
How to make one: eight chapters, a prep list, the recording and the markers
A recorded codebase walkthrough is made in 4 stages: plan eight chapters with the files each one opens, prepare a screen with no secrets or customer data, record one take per chapter, and publish it with chapter markers plus a contents list kept in the repository.
The running order below is my working order for a tour of 20 to 30 minutes. What each recording tool and video host does comes from its own help pages, read when this page was written.
The eight chapters, with minutes
A codebase tour, by my plan, has 8 chapters in about 28 minutes: what the app does, how to run it, the repository map, one request traced end to end, the data model, where state lives, integrations and deploys, and the decisions a newcomer would undo by mistake. The traced request runs longest because it ties the others together.
| Chapter | Minutes | What to show on screen | What the viewer can do afterwards |
|---|---|---|---|
| 1. What the app does and for whom | 2 | The running product, signed in as a demo user, one core task from start to finish | Say who uses the app and what for |
| 2. How to run it | 3 | Clone, install, environment variables by name with values hidden, seed data, the dev command, the environments that exist | Start the app on their own machine |
| 3. The repository map | 4 | Top-level folders, the two or three entry points, where generated code lives and must not be edited | Find the folder a feature lives in |
| 4. One request traced end to end | 5 | A click in the interface, the API route, the validation, the database call, the response, with the file open at each step | Follow a change from the screen to the database and back |
| 5. The data model | 4 | The main tables, their relations, the access rules and the files where they are defined | Say which table holds what and who can read it |
| 6. State and the source of truth | 2 | Where the client keeps state and which copy wins | Tell which value is right when two disagree |
| 7. The outside world | 4 | Integrations, webhooks, scheduled jobs, where secrets live, how a deploy happens | Name every outside service and how code reaches production |
| 8. Decisions and warnings | 4 | The three or four choices a newcomer would undo by mistake, known risks, what to read next | Leave a deliberate choice alone |
The minutes are a plan, not a rule; the constraint I hold to is the 20 to 30 minute total. Say each chapter title out loud as it starts, so the transcript carries the markers too.
The second chapter assumes the app starts at all. When a new developer cannot run the project locally, fix that before recording. The fourth chapter is where a typed contract at the API boundary shows on screen or is visibly missing, the same contract that matters when the frontend broke after a backend change. Tracing a request live, with the next developer asking questions, is a working session, part of what to give a developer taking over your app; the recording is the version a later hire can replay. The sixth chapter is short unless the app is one where two screens show different values, in which case it shows which copy of the data is meant to win.
Before you record: the prep list
Nine things to settle before pressing record, all of them my working rules:
- An outline with the file paths for each chapter, not a script.
- A demo account and seed data, so no real customer appears.
- Every
.envfile, secrets manager tab and terminal history closed or cleared. Secret values never appear on screen; say the names only. - Notifications off on every device in the room.
- A clean browser profile with no personal bookmarks or signed-in accounts.
- An editor font large enough to read on a laptop screen.
- Capture at 1080p, my default.
- A microphone test, played back once.
- The commit hash and the date ready to say in the first ten seconds, because a tour describes one moment of the code.
If a secret does appear on screen, rotate it. Editing the video is not the fix, because a published frame may already be cached or downloaded; that is my working rule.
Recording it, and adding chapter markers or a contents list
Chapter markers are timestamps that let a viewer jump to one part of the tour. Put them in the player where it supports chapters, and always in a contents list in the repository with the date, the commit and one line per chapter. The list outlives any video host.
Any screen recorder can do the job: Loom, OBS Studio, QuickTime, or a video call recorded with only yourself in it. Each has its own limits. Loom’s help center says “Loom Starter users have a 5-minute recording duration limit,” and its pricing page lists Starter as the free plan, so on that plan I’d record a tour of 20 to 30 minutes chapter by chapter, or use another tool. One take per chapter is easier to redo than one long take anyway; join the takes afterwards or keep them as a playlist. That is my working rule.
Markers inside the player work where the host supports them. YouTube’s rules for video chapters say the first timestamp in the description must start with 00:00, the video needs at least three timestamps in ascending order, and the minimum length for a chapter is 10 seconds. Loom’s help center says you can add chapters to any Loom “by adding a list of ascending timestamps and chapter titles,” and that chapters “must start at 0:00 and be at least 5 seconds long”; its pricing page lists Auto Chapters under the Business + AI and Enterprise plans.
The second place, always, is a WALKTHROUGH.md file next to the README: the link, the date, the commit hash, then one line per chapter with its timestamp and the files shown. The timestamps and paths below are made up, as an example:
# Codebase walkthrough
Recording: <link to the original file in the client's storage>
Recorded: <date> · Commit: <commit hash>
Captions: <link to the corrected caption file>
00:00 1. What the app does: running product, demo account
02:00 2. How to run it: README.md, .env.example, scripts/seed.ts
05:00 3. Repository map: src/, src/app/, src/lib/generated/
09:00 4. One request traced: src/app/api/orders/route.ts, src/lib/db.ts
14:00 5. Data model: supabase/migrations/, access policies
18:00 6. State: src/stores/cart.ts
20:00 7. Outside world: webhooks, scheduled jobs, deploy workflow
24:00 8. Decisions and warnings: docs/decisions/The contents list is the part that survives a change of video host, and a text search of the repository finds it.
Accessible means captions, with a transcript as a useful extra. WCAG’s captions criterion for prerecorded media, success criterion 1.2.2 at Level A, reads: “Captions are provided for all prerecorded audio content in synchronized media, except when the media is a media alternative for text and is clearly labeled as such.” Auto-captions get a correction pass for file and function names before handover; that is my working rule. A transcript also makes the tour searchable, so “where is the webhook handler” becomes a text search instead of a scrub through the video.
Where it lives, who owns it, and when to re-record
The file lives in storage the client owns, their drive or their video account, unlisted or private, with access for the people who need it. The agency hands over the original file, not only a link. Both are my working rules. The README links to WALKTHROUGH.md, so anyone who opens the repository finds the tour.
Re-record a chapter when its subject changes, such as a new auth provider or a moved deploy, and write the new date on that chapter’s line in the contents list. Tools that generate a codebase tutorial automatically can draft the repository map. In my reading they cannot say why a decision was made or which part not to touch, so their output is prep material for the third chapter, not the tour.
How to verify it
A codebase walkthrough is verified with my 7 checks: it plays for the client’s account, runs 20 to 30 minutes, every marker lands on its chapter, captions exist, no secret appears, the commit is stated, and a stranger who watches once can run the app, find a feature’s file and locate the secrets.
In the Production Hardening Sprint, deliverable 10.9, Recorded codebase tour, is verified this way: deliver an accessible recording with chapter markers or a short contents list. The checks below work for any host the client owns.
- 01 Open the link in a private window, signed in as the client's account, or signed out for an unlisted link. Pass: it plays. Fail: it asks for the agency's login.
- 02 Check the total length. Pass: between 20 and 30 minutes. Fail: shorter, or one long take that runs well past it.
- 03 Click each marker or contents-list timestamp. Pass: each one lands on the chapter it names. Fail: a timestamp opens in the middle of a different chapter.
- 04 Open the captions, and the transcript if there is one. Pass: captions exist, and the file and function names in them are spelled right. Fail: no captions, or auto-captions nobody corrected.
- 05 Scrub through at double speed. Pass: no secret value and no real customer data in any frame. Fail: either one appears, which means rotating the secret, not only cutting the frame.
- 06 Listen to the first ten seconds. Pass: the date and the commit are stated, and that commit exists in the client's repository. Fail: no commit, or one the client's repository does not have.
- 07 Run the stranger test: someone who has never seen the repository watches once, then, without help, runs the app locally, finds the file that handles one named feature, and says where the secrets live (the store, never a value). Pass: three of three. Fail: any miss, and the miss names the chapter to redo.
Keep three things as evidence: the WALKTHROUGH.md file in the repository, the location of the original recording, and the stranger test’s three results with the date.
Where the sprint does this
Deliverable 10.9 is the recorded codebase tour: we record a 20 to 30-minute walkthrough of the repository, data model, and key architectural decisions. Deliverable 13.4 is the live session, where we conduct and record a 60-minute walkthrough with the client team and technical advisors. The homepage lists both among what you receive at handover: a recorded 60-minute handover and a 20 to 30-minute codebase tour. The diagram the tour points at is deliverable 13.2, which shows the deployed components, data flows, authentication boundaries, and third-party integrations. Deliverable 13.1, the production readiness report, delivers the result for every scope item, the work completed, and its verification evidence. New features that change the product’s core capabilities are separate work. The tour is listed in the published scope, area 10, and the other three deliverables in area 13.
If you are the client: what to ask for
If an agency or freelancer has promised you a walkthrough, these five asks turn the promise into something you can check.
- 01 The tour itself, written into the agreement, with its 20 to 30 minute length and the eight chapters from the chapter table above.
- 02 The original file, stored in an account you own, as the section on where it lives describes.
- 03 A
WALKTHROUGH.mdcontents list in your repository, in the format shown under the markers section. - 04 Captions with file and function names corrected, plus a transcript if you want to search the tour.
- 05 One run of the stranger test by someone on your side, scored as the verify section describes.
The rest of what a delivery owes you, such as accounts, domains and the last invoice, is outside this page.
Owning an app means being able to run it, change it and recover it without guessing. The sprint below leaves you with the runbooks and documentation to do that.
Built it with AI. Now it has to hold up for real customers.
The Production Hardening Sprint takes the app you already have and builds the production foundation underneath it. Authentication and access rules, payments that stay consistent, error handling, monitoring, backups, automated tests and a documented handover. Our engineers work inside your existing codebase for ten working days. All 123 deliverables are included, and you get the evidence for each one.
See the Production Hardening Sprint → 
$2,500 fixed price · 10 working days · One codebase