How to onboard junior reviewers on to Mason

Bringing a junior plan reviewer onto Mason is not the same problem as bringing a senior reviewer onto Mason. A senior already knows the code. They know what a real comment looks like. When Mason flags something, they can tell in five seconds whether the flag is right, wrong, or interestingly wrong. A junior cannot do any of that yet — and if you hand them Mason on day one without structure, you risk teaching them to trust the tool instead of teaching them the code.

That is the failure mode worth taking seriously. A junior who learns to lean on Mason before they have learned the underlying material does not become a faster reviewer. They become a reviewer who cannot work without Mason and cannot tell when Mason is wrong. Both of those are bad.

The good news is that the fix is not complicated. Four practices, applied consistently during the first six months, produce junior reviewers who use Mason the way a senior does — as a second pair of eyes, not a first one.

1. Mason comes after the first pass, not before The rule we recommend for new reviewers: read the plans yourself, mark up what you find, then run Mason. Not the other way around.

The reason is simple. If a junior runs Mason first, they are no longer reviewing the plans. They are auditing Mason's output, which is a completely different cognitive task and one that requires more code knowledge than they have yet. They will miss things Mason misses, because they have stopped looking. And they will not build the muscle of finding issues unaided, which is the muscle the job actually requires.

After the first pass is done and the junior has their own list, Mason becomes useful in the way it is meant to be useful: as a check on what they caught and a prompt for what they may have missed. The order matters. First-pass-then-Mason builds reviewers. Mason-then-skim builds dependents.

2. Always second-guess Mason Mason is good. It is not infallible, and juniors need to internalize this early — before they have built up the experience to notice when something is off on their own.

Every Mason flag is a hypothesis, not a finding. The junior's job is to verify it: read the cited section, look at the plan, decide whether the flag actually applies to this project, this jurisdiction, this scope. Sometimes Mason is right and the comment goes through unchanged. Sometimes the cited provision does not apply. Sometimes the flag is technically correct but practically irrelevant. Sometimes Mason has missed a related provision that changes the answer. A junior who sends Mason's output to a client without checking it will eventually send something embarrassing. A junior who checks every flag will, over a few months, develop the instinct for which kinds of flags need the most scrutiny.

The framing we suggest to leads: treat Mason like a confident colleague who is usually right but occasionally wrong, and whose work you would always read before signing your name to it.

3. Use the code book links — every time Mason links every comment to the underlying code section. Juniors should click those links. Every time. For at least the first six months.

This is the single most-skipped step, and the one with the highest cost when it gets skipped. Juniors are still learning the code books. Mason is not a shortcut around that learning — it is a tool that becomes useful because of that learning. A reviewer who has read the actual section can tell whether Mason has cited it correctly, whether there is a relevant exception Mason did not surface, and whether a neighboring section changes the picture. A reviewer who has only read Mason's summary cannot tell any of those things.

Reading the underlying text is also how juniors build the structural knowledge of the code that lets them work fast later on. Every time they click through to a section, they are slowly mapping the code in their head — what is in Chapter 3, what is in Chapter 10, how the chapters relate. That map is what eventually lets a senior reviewer find an answer in ninety seconds. Mason can shorten the path to a citation, but it cannot build the map. Only reading does that.

4. Don't skip QA during the transition When a firm first rolls Mason out to juniors, there is a tempting line of reasoning: "Mason caught the major items, the junior verified them, the senior looked at the comment letter — we don't really need the formal QA pass anymore."

This is the wrong call, especially in the first three to six months. The transition period is exactly when QA is most valuable, because it is when you are still learning how your juniors interact with Mason — what they over-trust, what they under-check, what kinds of errors slip through the new workflow that did not slip through the old one. Skipping QA during the transition means flying blind through the period where you most need the data.

Keep the full QA pass through the onboarding window. Once you have a few months of QA results showing where the new workflow is solid and where it is not, you can adjust. Cutting QA before you have that data trades a known control for an unknown risk, and the risk shows up in client-facing comment letters.

Closing None of this is exotic. The pattern is: do the work first, check the tool, verify against the source, and keep the safety net up while you adjust. Firms that follow it produce juniors who become genuinely strong reviewers — reviewers who use Mason well because they understand what Mason is doing and where it can be wrong.

Change takes management. Not changing is unmanageable. The firms getting the most out of Mason are not the ones who deployed it fastest. They are the ones who were most deliberate about how their juniors learned to use it.