Format-First
Records are easy to read, easy to lint, and stay stable under diff. V2 adds tags and sweep patterns for coverage tracking.
A compact, lintable format and toolchain for pairing content with single-line feedback. Inline, compact, and sidecar modes with sweep-capable coverage tracking.

MarkBack is a compact, human-writable format and toolchain for labeling content with feedback in a single, lintable line. It keeps raw content and evaluation notes together so you can iterate prompts, train evaluators, and track revisions without inventing a custom schema.
%markback 2
@id prompt-001
@tag training
# API Design Task
Create an endpoint that:
- **GET** `/users/{id}`
- Returns JSON with `name`, `email`
- Handle 404 for missing users
<<< approved; clarity=high; needs=error examplesThe content (Markdown) stays readable. The <<< line captures feedback. Try it live →
Prompt iteration usually scatters content, labels, and reviewer notes across JSON, spreadsheets, and ad-hoc scripts. MarkBack standardizes that feedback loop in a text format that works in Git, can be linted, and scales from a single prompt to thousands of records.
content + feedback -> MarkBack records -> lint / normalize -> prompt iteration