Agda
Hacker ApprovedRanked 4 of 8 proof assistants by recommenders
Dependently typed proof assistant people prefer for interactive proof checking and math exploration; critics say it is impractical for building ordinary software and has little AI training data.
Dependently typed proof assistant people prefer for interactive proof checking and math exploration; critics say it is impractical for building ordinary software and has little AI training data.
24 people gave an opinion
- recommend it
- 19
- criticize it
- 5
- approval share
- 79%
Recommended in 9 of 13 months
- November 2025: not recommended
- December 2025: recommended
- January 2026: not recommended
- February 2026: recommended
- March 2026: recommended
- April 2026: recommended
- May 2026: recommended
- June 2026: not recommended
- July 2026: recommended
- August 2026: recommended
- September 2026: recommended
- October 2026: recommended
- November 2026: not recommended (month in progress)
Why it carries the badge
- 19 people recommend itNeeds 10 or more, met.
- 3.8 recommenders for every criticNeeds 2 to 1 or better, met.
- Recommended in 9 of 13 monthsNeeds 4 or more, met.
The same three rules apply to every product, and the badge can’t be bought. How the badge works
What people say about it
The reasons people give, with the number of comments that give each one. Open a reason to read what they said.
Why people recommend it
Each mark is one comment
Preferred for interactive proof checking
“uses the Agda proof assistant in exactly this sense, as a kind of interactive blackboard for taking notes”
Comment from 8 Sep 2026 in “Finding a bug in Dummit and Foote's Abstract Algebra” “Agda is my first choice for proof checker and for math-y explorations”
Comment from 28 Apr 2026 in “"Why not just use Lean?"” “For proof checking I actually prefer Agda.”
Comment from 17 Oct 2026 in “I built the RealWorld app in Lean 4” Helpful interactive tooling and developer support
“the tooling was interactive in a helpful way I've never experienced with other languages”
Comment from 27 Jul 2026 in “We have proof automation now” “These are very high level functional languages with sophisticated developer tooling.”
Comment from 18 Oct 2026 in “Programming Language Foundations in Agda” Elegant, beautiful language design
“extremely elegant yet flexible mixfix notation mechanism”
Comment from 27 Apr 2026 in “"Why not just use Lean?"” “Agda and Idris are more beautiful for sure”
Comment from 22 Jul 2026 in “Introduction to Formal Verification with Lean Part 1” Pattern matching and dependent types
“They work with pattern matching not just for definitions but for proofs as well, so the derivation is laid bear.”
Comment from 18 Oct 2026 in “Lean now ships with verified kernels” “I loved Agda 2 as a dependent type language”
Comment from 22 Feb 2026 in “Parse, Don't Validate and Type-Driven Design in Rust”
What people warn about
Each mark is one comment
Not practical for building software
“I prefer agda as proof checker but its not a practical choice for building software.”
Comment from 27 Apr 2026 in “"Why not just use Lean?"” “has a more proof-assistant flavor than an actual programming language flavor”
Comment from 27 Aug 2026 in “We found a division by zero bug in FFmpeg with a vibecoded fuzzer” Little training data for AI
“It's one of the few languages I've seen that's sufficiently unrepresented in training data.”
Comment from 27 Apr 2026 in “"Why not just use Lean?"” “Agda will have little training data so the result will not be nearly as good”
Comment from 12 Aug 2026 in “Why Go Is an Ideal Language for AI-Assisted Software Engineering”
Other proof assistants people recommend
The four most recommended other proof assistants, with the same counts for each, so you can compare like for like. The tick on each bar marks the 2 to 1 line the badge needs.
See all 8 proof assistants, rankedWhat people said
31 of the 34 comments that mention it, newest first. Each links to the original comment.
“These are very high level functional languages with sophisticated developer tooling.”
“They work with pattern matching not just for definitions but for proofs as well, so the derivation is laid bear.”
“I highly recommend Haskell fans explore Lean/Agda/Idris”
“For proof checking I actually prefer Agda.”
“Most proofs are basically write-only and impossible to maintain”
“uses the Agda proof assistant in exactly this sense, as a kind of interactive blackboard for taking notes”
“has a more proof-assistant flavor than an actual programming language flavor”
“Agda will have little training data so the result will not be nearly as good”
“other languages such as Agda, Idris, and Rocq that would be fantastic replacements to Lean”
“the tooling was interactive in a helpful way I've never experienced with other languages”
“their performance has improved a lot”
“Agda and Idris are more beautiful for sure”
“non-slop Lean/Agda/Rocq/... formalizations are amazing for understanding proofs”
“anything short of Agda or Lean falls short in terms of Real™ Category Theory”
“I find the LLM as interactive tutor reviewing my work in a proof checker to be a really killer combo.”
“Agda is my first choice for proof checker and for math-y explorations”
“another major concern for me is the inscrutability of Agda's error messages”
“Its also really slow and doesn't have a huge library ecosystem”
“I think what holds Agda back from being "practical" is that it just doesn't have good tactics.”
“I prefer agda as proof checker but its not a practical choice for building software.”
“Agda worked out of the box with macOS homebrew.”
“Agda's documentation is kind of bad and it's a pain to get it working on your system”
“It's one of the few languages I've seen that's sufficiently unrepresented in training data.”
“extremely elegant yet flexible mixfix notation mechanism”
“All the Haskell people from Chalmers have produced very interesting work.”
“Agda is not Turing-complete, yet it is very useful.”
“Agda can compile to Haskell”
“If you like the Haskell interop then I'd recommend staying with Agda.”
“I loved Agda 2 as a dependent type language”
“It’s not as hard as the author suggests.”
“If you push this idea further: use Lean, Agda or Rocq.”
Counts come from 1,795,640 Hacker News comments, November 2025 to November 2026. How we count. Report a mistake.