Overview
Seamline keeps Figma, code, Storybook and docs in sync for Primer.
- It checks all 74 components across the four sources.
- Nemotron fixes what it's sure of (≥ 85%) and logs every change.
- It leaves the rest to you, and the PR stays red until you decide.
All sources in sync
Needs you
Agent
Agent log
Components
Button
Checks
Button checks
Changed by the agent
Only calls at 85% confidence or more are applied. Each one can be undone.
What the agent did
TimelineLast run, in order
Decisions
What the agent won't decide alone: conflicts where both sides changed, calls it wasn't sure about, and new options it won't create without you.
To decideEverything here blocks the pull request. Debora decides as design system lead (CODEOWNERS)
In screens
Out of sync elsewhereNemotron Ultra suggests a fix · assign it or mark it as not needed · doesn't block the PR
Missing somewhere
How it works
A component should look and behave the same in Figma, code, Storybook and docs, and stay that way when it's used in a screen. Seamline checks three layers on every run.
What it watchesThree layers, one run
Who does whatRules first. Models only where judgement is needed
When one side changesFive kinds of change, and who handles each
Keeping the models honestWhere a model could tilt a decision, and what checks it
Guardrails
Applies only at ≥ 85% confidenceEvery change is logged and can be undone3 rejections pause auto-apply for that kindThe GitHub check (ds-sync) re-checks every pull request
The proofBroken on purpose, then checked
Every break we planted was caught
Sync strategiesTested on Primer's Button
We made the five changes to Button and synced them four ways. Each strategy ran in its own Nebius Token Factory Sandbox, forked from the same checkpoint.
ResultSelect a row to see what broke
Where each one breaksChecks still off after the sync. The agent's are waiting on a person
Design system health
What went out of sync in the last run, what the agent fixed, and what it cost. Provisional until the open decisions are answered.
What went out of sync, by areaChecks off before the agent and after it
Sources
Where the design system lives, and the services Seamline uses to keep it in sync.
Design systemRead on every run
ServicesWhat the agent runs on