# sem

19 Hacker News commenters recommended sem and 7 criticized it, November 2025 to November 2026. It was recommended in 5 of 13 months. It meets the Hacker Approved badge rule.

**Verdict:** Shows which functions and classes changed rather than lines, layered on Git with no repo migration. Critics say it would be rough on something like the Linux kernel.

## Why people recommend it

- Works on top of Git (3 comments): "sem stays on top of git so there's zero migration cost, you keep your existing repo and workflows." ([source](https://news.ycombinator.com/item?id=47305684)) "A step in the right direction, and interesting in that it layers over existing git" ([source](https://news.ycombinator.com/item?id=48430769)) "sem computes semantic diffs on top of your Git repo—no repo rewrite needed." ([source](https://news.ycombinator.com/item?id=46920949))
- Wide language support via tree-sitter (3 comments): "extracts entities from 30+ languages via tree-sitter and builds a cross-file dependency graph" ([source](https://news.ycombinator.com/item?id=47957703)) "I'm glad someone else already implemented it with support for more languages." ([source](https://news.ycombinator.com/item?id=47298119)) "working across multiple languages with a single tool can be quite helpful" ([source](https://news.ycombinator.com/item?id=48429494))
- Shows changed functions, not lines (2 comments): "When AI agents are committing hundreds of changes a session, you need to know which functions changed, not which lines" ([source](https://news.ycombinator.com/item?id=47296542)) "Instead of showing you which syntax nodes changed, it shows you which functions, classes, and methods changed" ([source](https://news.ycombinator.com/item?id=47556225))
- Ignores cosmetic changes, fewer false conflicts (2 comments): "purely cosmetic changes like reformatting or renaming a local variable won't show as a diff" ([source](https://news.ycombinator.com/item?id=47305669)) "that level of understanding is enough to resolve 100% of false conflicts on our benchmarks" ([source](https://news.ycombinator.com/item?id=47305708))

## What people warn about

- Overrides git diff, hard to undo (3 comments): "I'd remove setup/unsetup commands and replace with a note that if you want to use it for git diff" ([source](https://news.ycombinator.com/item?id=48433010)) "But there are no instructions for how to reverse those actions if you don't like the tool." ([source](https://news.ycombinator.com/item?id=48430346)) "incredibly obnoxious that it overrides default git diff" ([source](https://news.ycombinator.com/item?id=48432921))
- Real-world value still unproven (2 comments): "I doubt if this actually solves a real problem for humans or agents" ([source](https://news.ycombinator.com/item?id=48430084)) "I am not sure if these are ready for prime-time yet." ([source](https://news.ycombinator.com/item?id=47451113))
- Overclaims, benchmarks favor sem (2 comments): "The benchmarks aren't great, they're super specific to sem's output" ([source](https://news.ycombinator.com/item?id=48429831)) "Your tool is cool. Sell it for what it is. Not for what it's not." ([source](https://news.ycombinator.com/item?id=48430333))

## Alternatives hackers recommend

- [difftastic](https://hackerapproved.com/p/difftastic.md): 23 recommend
- [Weave merge tool](https://hackerapproved.com/p/weave.md): 20 recommend
- [Mergiraf](https://hackerapproved.com/p/mergiraf.md): 19 recommend
- [Meld](https://hackerapproved.com/p/meld.md): 12 recommend
- [Beyond Compare by Scooter Software](https://hackerapproved.com/p/beyond-compare.md): 9 recommend

## Cite as

Hacker Approved, "sem", https://hackerapproved.com/p/sem/ (counts from 1,795,640 Hacker News comments, November 2025 to November 2026).