DHH claims agents implemented and optimized the entire Campfire web app in Elixir, Go, and Ruby-replacing ports — conceding Ruby is slowest and asking 'if you're no longer reading the code?' — and whether the three ports in basecamp/once-campfire hold up under inspection, or other prominent builders replicate whole-app agentic porting, establishes whole-application agentic implementation as working practice rather than provocation.

state: watchingheat: lowuncertainty: mediumconvergesscott: highagentic-coding whole-app-implementation cross-language-portingDavid Heinemeier Hansson (DHH)37signalsBasecamp

What is this?

Campfire is 37signals' open-source, self-hostable Ruby-on-Rails chat app (sold as ONCE, open-sourced September 2025). DHH — Rails creator and 37signals CTO — claims his coding agents implemented and optimized the entire app in Elixir, Go, and Rust, conceding Ruby is the slowest version; a public basecamp/once-campfire-rust repo with a detailed conversion plan (compatibility contracts against the pinned Ruby upstream) corroborates the Rust port as a real engineering effort, while the supplied snippets do not independently verify the Elixir and Go ports or the 'agents wrote all of it' attribution. The claim lands amid DHH's August–September 2026 Lex Fridman interview and Rails World keynote, where he says agents write 100% of his new-project code, calls the agentic shift bigger than the web, and warns unsupervised 'vibe coding' wrecked architecture during Basecamp 5 — positioning the ports as proof-of-work for disciplined agentic engineering. Meanwhile the Ruby ecosystem is pushing back from within: Ruby Weekly reports Matz used the experimental Roundhouse compiler to run Campfire in 12× less memory, attacking the 'Ruby is slowest' premise directly.

Why it matters to Scott

DHH — a maximally consequential other party — independently arrives at practice Scott's canon already holds and runs: whole-app agent implementation verified not by reading code but by compatibility contracts against the pinned Ruby upstream, which is characterisation-testing/specification-as-asset in the wild, and his 'no longer reading the code' concession is Scott's trust-the-tests-not-the-AI thesis (verification-cost, ai-legacy-takeover) stated by someone else — a dated-receipts publishing opportunity that also mirrors the whole-app agent builds in all_in_one_software. The Matz/Roundhouse counter (Campfire in 12× less memory) adds a live test of the regeneration-economics fork — port to a new language vs fix the kernel — and Scott's model-plus-harness unit is the right instrument for the unverified part: only the Rust port is corroborated, and 'agents wrote all of it' is unverifiable without harness disclosure.

ip:concept.characterisation-testingip:concept.specification-as-assetip:concept.verification-costip:framework.ai-legacy-takeoverip:concept.regeneration-economicsip:concept.model-plus-harness-benchmark-unitdev:project.all-in-one-softwareradar:checkly-agentic-go-rewriteradar:mirrorcode-long-horizon-reimplementationradar:github-copilot-rust-runtime-migrationradar:cobol-java-agent-migration-validationradar:canonical-c-to-rust-project

queries asked of Scott's wikis

agent-written code review workflow
cross-language porting verification harness
framework conventions agent writability
vibe coding architectural drift critique
whole-application agent capability benchmark
self-hosted single-repo app stack

Measured heat

now 0 pts/hpeak 31 pts/hcomments 0/hpeers p16momentum: steady3 platformsage 194h

points/hour across evidence · reading as of 2026-10-12 02:59:37.977291+11:00 · deterministic, not a model opinion

How the heat travelled

10-04 20:08	⭐ origin directly observed	I've had agents implement and optimize the Campfire web app in Elixir, Go, Rust tosh on hacker news	—
10-03 14:00	first on x (echo) · published · +-30.1h	"I've had agents implement and optimize the Campfire web app in Elixir, Go, and Rust. Yes, Ruby is the slowest. I didn't care about that whe DHH (@dhh)	—
10-05 12:44	first on r/ClaudeAI · published · +16.6h	I rewrote Flutter in Rust lol edTheGuy00	—
10-06 13:09	first on hacker news · published · +41.0h	Show HN: A modern low-poly SimCity 2000 clone, built by Opus 5.5 drdator	—
10-04 20:08	amplified on hacker news	hn.story.49957334 tosh	peak 5 · 1 comments · 4% of case engagement
10-05 12:44	amplified on r/ClaudeAI	reddit.post.1wy7lg3 edTheGuy00	peak 63 · 29 comments · 35% of case engagement
10-06 13:09	amplified on hacker news 👑	hn.story.49977886 drdator	peak 37 · 26 comments · 44% of case engagement
10-09 17:00	amplified on hacker news	hn.story.50023409 kinabalu76	peak 21 · 3 comments · 17% of case engagement
10-04 20:20	our radar first saw it · +0.2h	discovery anchor: hn.story.49957334	—

pace: p72 vs 1188 stories at the 168h mark (now 194h old) — ahead of grok-trump-venezuela-decision (1.0x), behind naiveai-n05-flash-release (1.0x)

Evidence (5) — ⭐ canonical anchor

source	object	author	score	comments
🟧 hn ⭐	I've had agents implement and optimize the Campfire web app in Elixir, Go, Rust Retrieved article excerpt Open article · Retrieved 2026-10-04T20:26:37.372130+00:00 [@dhh](https://x.com/dhh) [DHH](https://x.com/dhh) [37signals](https://x.com/37signals) [@dhh](https://x.com/dhh) I've had agents implement and optimize the Campfire web app in Elixir, Go, and Rust. Yes, Ruby is the slowest. I didn't care about that when the pay-off was huge in terms of productivity and developer joy. But if you're no longer reading the code? [github.com/basecamp/once-…](https://github.com/basecamp/once-campfire) [6:14 PM · Oct 4, 2026](https://x.com/dhh/status/2106810173683851564)·[93.4K Views](https://x.com/dhh/status/2106810173683851564) [165](https://x.com/compose/post?in_reply_to=2106810173683851564) 34 913 261	tosh	5	1
🟧 echo.x	"I've had agents implement and optimize the Campfire web app in Elixir, Go, and Rust. Yes, Ruby is the slowest. I didn't care about that whe	DHH (@dhh)	—	—
🟠 reddit	I rewrote Flutter in Rust lol ClaudeAI	edTheGuy00	63	29
🟧 hn	Show HN: A modern low-poly SimCity 2000 clone, built by Opus 5.5	drdator	37	26
🟧 hn	Kotlin keeps up with Rust in DHH's Campfire rewrite	kinabalu76	21	3

Interpretation history

2026-10-10T00:25:57Z
DHH's own follow-up (hn.story.50023409) adds a fourth port (Kotlin) with performance details — first-party evidence on the Campfire ports, but from the same actor. The Rust port remains the only independently corroborated engineering effort (compatibility contracts). Elixir/Go ports still unverified; Community Note challenging benchmarks remains under X fact-check. The SimCity 2000 replication is indie, self-reported, and a decompiled-code translation — not a prominent-builder whole-app agentic port. Core-story attention decayed; new Kotlin post modest (21 pts/3 comments). Verification and replication prongs unchanged in substance.
2026-10-09T19:58:40Z
evidence attached: hn.story.50023409 — DHH's own follow-up with performance details on the Kotlin port is first-party evidence on whether the agentic Campfire ports hold up under inspection.
2026-10-07T01:20:22Z
The replication prong moves from unmet to weakly evidenced: an indie Show HN reports Opus 5.5 ported SimCity 2000 function-by-function from 940 Ghidra-decompiled PowerPC functions, claimed byte-exact against the original across 10k game days — the first independent instance of the behavioral-verification/contract pattern, though self-reported (1 pt / 0 comments) and a decompiled-code translation rather than a fresh trilingual rewrite, so 'prominent builders replicate whole-app agentic porting' remains unmet. Core-story attention is dead (~0 pts/h vs 24.7 peak, 82h old); the 24× velocity spike is on the Reddit Flutter-in-Rust proxy post only, so heat stays low.
2026-10-06T23:36:37Z
evidence attached: hn.story.49977886 — Opus 5.5's function-by-function Ghidra-decompiled SimCity 2000 port, byte-exact against the original across 10k game days, is the strongest independent replication yet of whole-application agentic porting holding up under inspection.
2026-10-05T14:26:47Z
First counterevidence arrived: a hidden Community Note in validation-gathering (surfaced via the HN thread) alleges the trilingual benchmarks compare non-equivalent implementations (Elixir funneling DB queries through a single GenServer with Redis jobs), putting the 'optimized / Ruby slowest' claim under formal fact-check on X — while the launch burst has fully decayed (~0.8 pts/h vs 23 peak, HN stalled at 5 pts/1 comment), so attention cools to low even as the verification question stays open. The Reddit Flutter-in-Rust post remains only a loose, non-agentic proxy for the replication prong: a 5-year gradual indie Rust-ification, not whole-app agentic porting with contracts.
2026-10-05T13:28:23Z
evidence attached: reddit.post.1wy7lg3 — Another whole-system agentic implementation instance — a 12-hour Fable 5 run producing a working Rust UI toolkit — feeding the case's replication question.
2026-10-04T21:25:26Z
anchor promoted to claim owner's artifact: echo.x.986d1a81a0 -> hn.story.49957334 — Fresh HN echo of the same DHH X post (Oct 4, 2026) already open as dhh-agents-campfire-trilingual-ports; attach and promote the anchor to the object carrying the claim owner's own tweet text (with the basecamp/once-campfire link).
2026-10-04T20:37:07Z
grounded: converges/high — DHH — a maximally consequential other party — independently arrives at practice Scott's canon already holds and runs: whole-app agent implementation verified no
2026-10-04T20:28:26Z
case created — High-authority first-party act with a public repo to verify against — a known production app implemented in three languages by agents, moving fast on X (93K views, 913 RTs within hours of posting).

Decision trace

10-10 11:31attention_routeThe editor compared this story and chose to keep watching.
10-10 11:25attention_candidatematerial_reprice
10-10 11:25repriceDHH's own follow-up (hn.story.50023409) adds a fourth port (Kotlin) with performance details — first-party evidence on the Campfire ports, but from the same actor. The Rust port remains the only
10-10 07:07attention_routeThe editor compared this story and chose to keep watching.
10-10 06:58attention_candidateattach
10-10 06:58attachDHH's own follow-up with performance details on the Kotlin port is first-party evidence on whether the agentic Campfire ports hold up under inspection.
10-10 06:58propose_attachDHH's own follow-up with performance details on the Kotlin port is first-party evidence on whether the agentic Campfire ports hold up under inspection.
10-08 00:59attention_routeThe editor compared this story and chose to keep watching.
10-07 12:20repriceThe replication prong moves from unmet to weakly evidenced: an indie Show HN reports Opus 5.5 ported SimCity 2000 function-by-function from 940 Ghidra-decompiled PowerPC functions, claimed byte-exact
10-07 10:36attachOpus 5.5's function-by-function Ghidra-decompiled SimCity 2000 port, byte-exact against the original across 10k game days, is the strongest independent replication yet of whole-application agenti
10-07 10:35propose_attachOpus 5.5's function-by-function Ghidra-decompiled SimCity 2000 port, byte-exact against the original across 10k game days, is the strongest independent replication yet of whole-application agenti
10-06 14:21sensor_dirtycomment_update
10-06 07:22sensor_dirtycomment_update
10-06 02:23sensor_dirtyvelocity_spike
10-06 01:26repriceFirst counterevidence arrived: a hidden Community Note in validation-gathering (surfaced via the HN thread) alleges the trilingual benchmarks compare non-equivalent implementations (Elixir funneling D
10-06 00:28attachAnother whole-system agentic implementation instance — a 12-hour Fable 5 run producing a working Rust UI toolkit — feeding the case's replication question.
10-06 00:25propose_attachAnother whole-system agentic implementation instance — a 12-hour Fable 5 run producing a working Rust UI toolkit — feeding the case's replication question.
10-05 08:25promote_anchorFresh HN echo of the same DHH X post (Oct 4, 2026) already open as dhh-agents-campfire-trilingual-ports; attach and promote the anchor to the object carrying the claim owner's own tweet text (wit
10-05 07:37groundDHH — a maximally consequential other party — independently arrives at practice Scott's canon already holds and runs: whole-app agent implementation verified not by reading code but by compatibil
10-05 07:28createHigh-authority first-party act with a public repo to verify against — a known production app implemented in three languages by agents, moving fast on X (93K views, 913 RTs within hours of posting).