Human memory fills in gaps, but not always correctly.
Ever been sure of a fact, only to find out you were wrong? Maybe you remember the Monopoly Man with a monocle. Or maybe you think the Berenstain Bears were spelled Berenstein.
Neither is true.
This is the Mandela Effect: when groups of people remember something the same way, but it’s wrong. It’s not just forgetting – it’s a false memory. It happens because our brains fill in gaps, repeat errors, or assume details that were never there.
In engineering, we do this, too. Not with monocles or children’s books but with:
- Code
- Systems
- Processes
- Or decisions
We think we remember how something works. Until we don’t.
Why documentation matters more than you think
Ask a developer about an old piece of code, and they’ll say: “Yeah, I remember how this works.”
But when they revisit it, they probably won’t. It’s human. We can only remember so much, especially when we’re thrown massive amounts of information daily.
It’s unlikely that a group of engineers will imagine a function that never existed. But details fade, and assumptions are not always correct.
This isn’t just a memory lapse, though – it becomes an engineering problem. Teams move on, projects grow, and what was once clear can easily turn into a guessing game. Code documentation is meant to prevent this, but often it can be incomplete, outdated, or missing altogether.
As an engineering manager (EM), you don’t write all the code. But you are responsible for making sure your team can understand, maintain, and build on it. That’s why documentation isn’t optional – or just a “nice-to-have.” It’s a strategic and deeply human necessity.
Documentation is a survival manual
Sometimes, you’ll have nowhere to turn to decode an obscure process, a vague variable, or a tangled service.
When that happens, good documentation is your lifeline:
- It clears up confusion
- Saves time
- And keeps projects moving
Without it, you’re left guessing, digging through code, and relying on memory. Which only wastes time and slows progress.
Documentation keeps teams on track. It records what they built and why decisions were made. It maps out complex systems and preserves key choices, making future work smoother and more efficient.
The silent onboarding hero
Imagine starting a new job with no guidance. Maybe it has even happened to you. No introductions, no explanations. Just a pile of code, little time, and an expectation to figure it out. That’s what onboarding looks like without proper documentation.
The truth is new engineers don’t need to feel lost or overwhelmed. Good documentation can be their map.
Instead of constantly asking teammates for help, new hires can:
- See how all the pieces of a system connect
- Understand the reasoning behind established decisions
- And get up to speed faster without relying on constant help
But onboarding is only part of the puzzle. Documentation helps everyone. It keeps knowledge from disappearing, makes handoffs easier, and improves teamwork.
It’s not just about convenience. It keeps knowledge with the team, not trapped in someone’s head.
The social glue of engineering
If you’re lucky, your team has that one person who is the “social glue.” Someone who organizes cake days, checks in on colleagues, and keeps the team spirit alive. They help build strong relationships.
Documentation is the technical equivalent. Just like social glue connects people, documentation holds a team’s knowledge together.
And it’s not just for one team. Documentation connects different roles in engineering, including:
- Frontend
- Backend
- Designers
- QA
- And others
Each role helps build and maintain complex systems. When documentation is strong, it holds teams together. When it’s missing, things fall apart.
Here’s why:
1 - Documentation is a central source of truth
It helps everyone understand how parts of a system connect. Instead of relying on:
- Scattered messages
- Meetings
- And word-of-mouth
Teams can use clear documentation for processes, APIs, and architecture decisions.
For example, a frontend developer shouldn’t have to guess how an API works. They should have clear documentation. The same goes for a QA engineer, who needs a guide for expected behavior and test cases.
2 - It supports remote and async work
Documentation is not only a pillar for in-office teams. Remote ones rely on written communication instead of quick in-person conversations.
Without documentation, knowledge is hard or timely to share. And if crucial details are missing, new hires get lost, mistakes happen, and work slows down.
A well-documented system allows team members to:
- Understand processes without waiting for answers
- Work asynchronously while staying aligned with objectives
- And onboard quickly and contribute sooner
3 - It enforces consistency
Every engineering team has unique workflows, best practices, and coding standards. Shared documentation helps enforce these standards across the company, ensuring, for example, that:
- Code reviews follow the same principles
- Development environments are set up consistently
- And feature releases follow a structured process
If shared documentation didn’t exist, every team would do things differently. This would result in inconsistencies, inefficiencies, and miscommunication.
Documentation isn’t only about writing things down so one doesn’t forget its existence. Instead, it’s about:
- Keeping teams connected
- Reducing friction
- And ensuring smooth collaboration across roles, locations, and projects
How AI is reshaping documentation
Let’s face it, writing documentation can be time-consuming. And this is one of the reasons why it gets overlooked. But AI tools are changing that. AI can automatically create and update docs using code comments and structure.
Tools like Cursor scan code and write docs based on function names, parameters, and comments. This keeps documentation up to date with no extra work from teams. Even when code is refactored, documentation will stay accurate.
And this is just a portion of the documentation. Other formats such as meeting transcripts, Slack threads, and Jira comments, can also be converted into documentation.
For example, imagine you want to add another service to your application. With the right documentation and standards, AI tools can write the service for you. In the same way, they will create the documentation for the new service.
AI tools also improve documentation by:
- Filling in knowledge gaps: They keep documentation structured, accurate, and easy to find.
- Maintaining consistency across teams: AI usually follows a standard structure. This allows everyone to work with clear, uniform documentation.
- Reducing errors and outdated information: AI spots missing details and inconsistencies. This helps teams keep their documentation accurate.
With automated updates, documentation stays current. Engineers can trust what they read – and spend less time second-guessing it. AI tools free engineers from repetitive and manual updates, allowing them to focus on more meaningful work.
But how much is enough?
This is a tough one, but there are some guidelines you can use.
Too much documentation can be overwhelming. Long and complex documents can make people skim through the content, overlooking details or entirely skipping them.
Too little documentation can be just as bad. The lack of instructions can lead to assumptions. And assumptions can lead to errors.
The best approach is to keep documentation lightweight, clear, and searchable. Instead of writing massive documents, focus on what teams actually need.
Try to keep your documentation:
- Concise: stick to the most important details
- Organized: use headings, bullet points, and short sections
- Easy to find: tools like Markdown files, Google Docs, or wikis are some examples for storing it
Remember, good documentation answers questions before they’re asked. It should guide engineers without forcing them to dig through endless pages. Shared knowledge should be a helpful tool, not a burden.
The short version: write it down, thank yourself later
Human memory isn’t perfect. Engineering is complex. Documentation connects the dots.
Without it, teams rely on memory, scattered messages, and endless meetings. This results in confusion, delays, and mistakes. Good documentation serves as a central source of truth. It ensures that teams stay connected and efficient, and helps with:
- Onboarding: new engineers can quickly understand systems without relying on others
- Collaboration: different roles (frontend, backend, QA, designers) work together smoothly
- Remote and distributed work: written knowledge allows teams to work asynchronously
- Consistency: shared documentation enforces best practices across teams
As an EM, you set the tone. If your team sees you documenting decisions and best practices, and making the knowledge visible – they’ll follow. And if they see you treating documentation as a chore? They will, too.
AI is changing documentation. It automates updates, generates docs from code, and keeps things consistent, taking the burden out of it.
Use simple tools to make it easy. Show its value by highlighting how it saves time and prevents mistakes. Make it a habit, not a task.
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Originally published on Medium.com
Content in this blog post by Alex Ponomarev is licensed under CC BY 4.0.
