Openprose

OpenProse, Inc. builds an open-source (MIT) programming language for AI sessions: standing AI jobs are declared as durable Markdown contracts (`*.prose.md` files) that state what should stay true, and the system works out how much model work it takes to keep it true. The language ships as an agent skill (`open-prose`) that runs on any compliant agent host such as Claude Code, Codex, or OpenCode, and is paired with Reactor — a deterministic harness (`@openprose/reactor` SDK plus the `@openprose/reactor-cli` `reactor` binary) whose model spend scales with surprise, not the clock: a render runs only when a node's subscribed input fingerprints move, and each commit is a content-addressed receipt with no LLM in the wake/commit decision. Contract kinds are responsibility, function, gateway, pattern, and test; Forme is the semantic dependency-injection layer that wires `### Requires` facets to `### Maintains` facets. A Y Combinator company founded in 2026 (San Francisco) with open-source traction; distributed as npm packages rather than a hosted REST API.

Openprose is profiled on the APIs.io network. Tagged areas include Company, AI Agents, Agent Orchestration, Developer Tools, and Open-Source.

Openprose’s developer surface includes documentation, API reference, getting-started guide, support, changelog, CLI, and 11 more developer resources.

🌐 Visit website 📡 Source on GitHub

21.0/100 emerging ▬ flat Agent 4/100 human only Full breakdown ↓
scored 2026-08-20 · rubric v0.12.0

0 APIs

CompanyAI AgentsAgent OrchestrationDeveloper ToolsOpen-SourceProgramming LanguageLLMWorkflow-AutomationY Combinator

Kin Score

Kin Score How this is scored →
scored 2026-08-20 · rubric v0.12.0

Composite quality — 21.0/100 · emerging

Contract Quality 0.0 / 25

Developer Ergonomics 12.9 / 20

Access Clarity 0.0 / 20

Operational Transparency 2.4 / 13

Contract Governance 0.0 / 12

Discoverability 5.7 / 10

Agent readiness — 4/100 · human only

Machine-Readable Contract 0 / 18

Agentic Access Contract 0 / 10

Documented Reversibility 0 / 6

MCP Server 0 / 12

Machine-Readable Auth 0 / 10

Idempotency 0 / 9

Stable Error Semantics 0 / 8

Request/Response Examples 0 / 7

Rate-Limit Signaling 0 / 7

Typed Event Surface 0 / 6

Agent Skills 5 / 5

Well-Known Catalog 0 / 4

Consent & Bot Identity 0 / 3

A2A Agent Card 0 / 8

Dry-Run / Simulate Mode 0 / 4

Improve this rating by publishing the missing artifacts — every area above can be raised, and the full rubric is at apis.io/rating/. This rating is computed from github.com/api-evangelist/openprose: open an issue to ask a question, or submit a pull request to add artifacts. Want it done for you? Prioritized profiling — $2,500 →

Get Started 2

Portal, sign-up, and the first successful call

DeveloperPortal

DeveloperPortal

GettingStarted

GettingStarted

Documentation 2

Reference material describing how the API behaves

Documentation

Documentation

APIReference

APIReference

Agent Surfaces 3

MCP servers, agent skills, and machine-readable catalogs

LLMsTxt

LLMsTxt

AgentSkill

AgentSkill

WellKnown

WellKnown

Design & Contract 1

Pagination, idempotency, versioning, errors, and events

Lifecycle

Lifecycle

Build 4

SDKs, sample code, and the tooling you integrate with

GitHubOrganization

Packages

SDKs

CLI

Access & Security 1

Authentication, authorization, and security posture

DomainSecurity

DomainSecurity

Operate 3

Status, limits, changes, and where to get help

Support

Support

ChangeLog

ChangeLog

ChangeLog

ChangeLog

Company 1

The organization behind the API

Website

Website

Source (apis.yml)

aid: openprose
name: Openprose
description: 'OpenProse, Inc. builds an open-source (MIT) programming language for AI sessions: standing AI jobs are declared
  as durable Markdown contracts (`*.prose.md` files) that state what should stay true, and the system works out how much model
  work it takes to keep it true. The language ships as an agent skill (`open-prose`) that runs on any compliant agent host
  such as Claude Code, Codex, or OpenCode, and is paired with Reactor — a deterministic harness (`@openprose/reactor` SDK
  plus the `@openprose/reactor-cli` `reactor` binary) whose model spend scales with surprise, not the clock: a render runs
  only when a node''s subscribed input fingerprints move, and each commit is a content-addressed receipt with no LLM in the
  wake/commit decision. Contract kinds are responsibility, function, gateway, pattern, and test; Forme is the semantic dependency-injection
  layer that wires `### Requires` facets to `### Maintains` facets. A Y Combinator company founded in 2026 (San Francisco)
  with open-source traction; distributed as npm packages rather than a hosted REST API.'
url: https://raw.githubusercontent.com/api-evangelist/openprose/refs/heads/main/apis.yml
x-type: company
x-source: vc-portfolio
x-backed-by:
- y-combinator
accessModel:
  pricing: unknown
  onboarding: unknown
  trial: false
  try_now: false
  public: false
  label: Unknown
  confidence: low
  source: []
  generated: '2026-07-22'
  method: derived
image: https://github.com/openprose.png
specificationVersion: '0.23'
created: '2026-07-17'
modified: '2026-07-20'
tags:
- Company
- AI Agents
- Agent Orchestration
- Developer Tools
- Open-Source
- Programming Language
- LLM
- Workflow-Automation
- Y Combinator
tags_raw:
- Company
- AI Agents
- Agent Orchestration
- Developer Tools
- Open Source
- Programming Language
- LLM
- Workflow Automation
- Y Combinator
apis: []
x-enrichment:
  date: '2026-07-20'
  status: enriched
  artifacts_added: 9
  pass: local-v1
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com
- FN: APIs.json
  email: info@apis.io
common:
- type: Website
  url: https://prose.md/
- type: DeveloperPortal
  url: https://prose.md/
- type: Documentation
  url: https://docs.prose.md/start/what-is-openprose
- type: APIReference
  url: https://docs.prose.md/sdk
- type: GettingStarted
  url: https://docs.prose.md/openprose/setup
- type: GitHubOrganization
  url: https://github.com/openprose
- type: Support
  url: https://github.com/openprose/prose/issues
- type: ChangeLog
  url: https://github.com/openprose/prose/blob/main/CHANGELOG.md
- type: LLMsTxt
  url: llms/openprose-llms.txt
- type: Packages
  url: packages/openprose-packages.yml
- type: SDKs
  url: packages/openprose-packages.yml
- type: CLI
  url: cli/openprose-cli.yml
- type: AgentSkill
  url: skills/openprose-open-prose.md
- type: Lifecycle
  url: lifecycle/openprose-lifecycle.yml
- type: ChangeLog
  name: OpenProse changelog (structured)
  url: changelog/openprose-changelog.yml
- type: WellKnown
  url: well-known/openprose-well-known.yml
- type: DomainSecurity
  url: security/openprose-domain-security.yml