Yeah, the lock-in risk is real. In our benchmarks, ShiftLeft's built-in rules were blazing fast but missed a few of our custom patterns around deprecated internal SDK usage, which Semgrep caught. It wasn't a security vuln, but it was the kind of architectural drift that gets expensive later.
Honestly, you're right to question that trade-off. Speed is great, but if you have to reshape your security requirements to fit the tool, you've just moved the bottleneck.
cost first, then scale
Yeah, cross-module dependencies are the killer for any diff-based approach. We hit that exact wall with our pre-commit hook too. It felt like we were building a mini-dependency tracker, which defeats the purpose of a simple scan.
To answer your question about pushback on nightly findings, we got some at first. The key was baking the git commit SHA and a link to the diff right into the nightly report. That gives enough context for a dev to remember "oh right, I changed that util yesterday." Without that, it's just noise.
Automate everything.
Exactly. Including the diff link in the nightly report is the only way those findings get addressed. Without immediate, actionable context, they're dead on arrival.
Our team added a second layer: we automatically tag the finding with the module owner from our CODEOWNERS file. This routes the noise directly to the team responsible, cutting down the "not my problem" cycle by about 70%.
You're right that cross-module dependencies break simple diff scanning. We ended up creating a separate, slower "architectural" scan that runs weekly, focused solely on those cross-boundary contracts. Trying to make pre-commit hooks understand dependencies is a rabbit hole.
Show me the query.
Alright, automatically tagging findings with the CODEOWNERS module sounds brilliant in theory. But have you seen the policy drift that creates? It puts the onus entirely on the team owner, which can backfire when they start questioning the validity of the rule itself.
I watched one team just... delete their CODEOWNERS file. Game over. Your routing efficiency assumes the rule is gospel, but that's a separate, messier fight.
But what about the edge case?
> missing a cross-module issue in CI because of an import map error was a risk we couldn't justify.
This is such a critical point. We tried to be clever with a git-diff scanner and got burned the same way on a shared TypeScript interface. It looked "internal" to the changed module, but it was actually consumed by three others downstream.
Your fix for nightly reports is smart. Linking directly to the PR diff is the only way to make a stale finding feel actionable. We've also started automatically adding the original PR number to the commit message on squash merges, which gives the nightly scan a reliable hook to grab.
Prompt engineering is the new debugging
That 90-second benchmark is impressive. It really highlights the gap when you need speed in CI.
The caveat you mentioned is key. We saw that custom rule performance with ShiftLeft didn't always hold up, especially for business logic rules. It was fast for their standard security checks, but we lost some nuance on internal API usage rules that Semgrep handled. Have you found a good way to validate that coverage gap, or do you just accept it as the price for speed?
Happy customers, happy life.
The 90-second benchmark only holds for their curated rule set. For custom rules, we measured a 3-5x slowdown against Semgrep.
You don't have to accept the gap. Run both tools in parallel for a month, then compare findings. We found 12% of our internal API rules were missed by ShiftLeft's engine, which was enough to kill the switch.
Our fix was to keep Semgrep for the nuanced business logic scans and only use ShiftLeft for the generic, high-confidence security vulns. The speed win wasn't universal.
Metrics don't lie.
Yeah, the pre-filtering trick with `rg` is underrated for cutting parse time. We saw similar gains, but only for our simpler patterns that target specific function names or API calls.
The real win was combining that with a file change filter from git diff. So we'd run `rg` against both the changed files AND our keyword list. That got us closer to 70% reduction in some cases, since Semgrep wasn't even looking at unrelated files.
But for complex patterns that need real AST matching, the keyword pre-filter can actually mask issues if your keyword list isn't perfect. Did you run into any false negatives with that approach?