YC Spring 2026 (P26) company

OpenProse

An open-source operating system for reliable long-running agents

About OpenProse

OpenProse is building open-source infrastructure for long-running AI work: a declarative language plus the Reactor harness/runtime for reliable agent workflows. Our organic open-source traction (7k+ installs) has already translated into a customer at a medical research lab, starting with a $10k pilot set to roll into a $10k/month contract. YC recruited us into the current batch and we've since hired two senior founding team members (ex-Google, Forbes 30u30 harness engineer). All three founding team members are two time founders. We've raised $1.25M in the last two weeks from Jonathan Abrams 8-Bit Capital, Otis Chandler, and other angels.

Public traction evidence

Each signal links to the public source used for attribution.

  1. X

    holy shit not that I’ve ever been a single issue voter and I’ve never voted for R for prez but there’s a not insignificant chance the iss…

    holy shit not that I’ve ever been a single issue voter and I’ve never voted for R for prez but there’s a not insignificant chance the issue of open source AI outweighs all the others combined and I did not have it on my bingo card that any of the candidates would have a policy...

  2. X

    it seems very likely that in 5-10 years you’re getting constant full body scans and constant non-invasive tumor removal the false positives objection is not sound

    it seems very likely that in 5-10 years you’re getting constant full body scans and constant non-invasive tumor removal the false positives objection is not sound

  3. X

    how to hyperstition without waluigistition

    how to hyperstition without waluigistition

  4. GitHub

    GitHub signal from openprose/prose

    openprose/prose: A new kind of language for a new kind of computer (TypeScript).

  5. X

    fable ran for just about 72 hours on this thing and only ever accumulated 42% of context (no compaction) in the top thread because it was doing everything in very rich dynamic workflows it came to a screeching halt last night, but not before it had rewritten the reactor from the Show more Quote dan @irl_danB · Jun 10 last night’s fable still reading out this AM on just 3 (!) of 10 multi-level dynamic workflows cloning the Reactor core into OpenProse OS (PrOS it called it), an upgrade (remote-first, agent-native) to the Reactor rebuilt from ground up fable is only 24% (!) of the way into top

    fable ran for just about 72 hours on this thing and only ever accumulated 42% of context (no compaction) in the top thread because it was doing everything in very rich dynamic workflows it came to a screeching halt last night, but not before it had rewritten the reactor from...

  6. X

    looking at the comments on this and the broader reception of the midjourney announcement by certain folks in the medical community just a fascinating level of pessimism the tech industry of the last 30 years has broadly let society down with its unrelenting focus on making Show more Quote dan @irl_danB · Jun 19 it seems very likely that in 5-10 years you’re getting constant full body scans and constant non-invasive tumor removal the false positives objection is not sound

    looking at the comments on this and the broader reception of the midjourney announcement by certain folks in the medical community just a fascinating level of pessimism the tech industry of the last 30 years has broadly let society down with its unrelenting focus on making Show...

  7. X

    the people saying this is a pivot never understood the intent behind the word midjourney

    the people saying this is a pivot never understood the intent behind the word midjourney

  8. X

    the present situation is coming into focus if the White House takes action against open weights the only people with the good models wi...

    the present situation is coming into focus if the White House takes action against open weights the only people with the good models will be foreign actors and domestic criminals should their models attack you (incidentally or on purpose) you are naked because the closed...