OpenSpec Custom Schemas (intent-driven-dev) — Summary

OpenSpec Custom Schemas by intent-driven-dev is a community schema library that extends the base OpenSpec CLI with six additional workflow flavors, each targeting a different delivery context: minimalist (user-story + Gherkin), event-driven (Event Storming → AsyncAPI), behaviour-driven (Gherkin scenarios throughout), intent-driven (proposal → Gherkin specs → design → ADR → tasks), linearized (Linear issue binding + spec mirroring), and spec-driven-with-ADR. The schemas plug in directly to OpenSpec's schema system via openspec schema validate and are activated by a single schema: key in openspec/config.yaml. The project demonstrates how OpenSpec's pluggable schema architecture lets domain-specific artifact graphs be distributed as copyable folder trees without forking the CLI. With 43 stars, a YouTube walkthrough, and a companion blog post, it is the most visible community schema pack for OpenSpec. The repository is maintained by a single contributor (the intent-driven.dev blog author) and was last updated in May 2026.

Compared to the seed references: closest to openspec (same CLI, same command surface, same artifact storage) but specifically adds the ADR artifact, AsyncAPI specification artifact, Gherkin requirement format mandates, and Linear project management integration — none of which appear in the default OpenSpec schema.

OpenSpec Custom Schemas (intent-driven-dev) — Overview

Origin

Published by the intent-driven.dev blog in February 2026 as the companion artifact to a blog post titled "OpenSpec Custom Schemas" (https://intent-driven.dev/blog/2026/02/12/openspec-custom-schemas/). A YouTube video walkthrough accompanies the release.

Philosophy

OpenSpec's default spec-driven schema is intentionally general-purpose. The intent-driven-dev schema pack demonstrates that domain-specific workflows — event-driven systems, behaviour-centric teams, teams using ADRs, teams using Linear — benefit from custom artifact graphs without reinventing the CLI. Each schema defines only the artifacts and their ordering; the delivery infrastructure remains OpenSpec.

Manifest Quote

From the README:

"Default OpenSpec includes the spec-driven schema, which is a strong general-purpose workflow. This repo adds more focused workflows for specific delivery contexts, and also demonstrates how to customise OpenSpec for different styles of work."

And the install guidance:

"Ask your coding agent to read this file and install the schema you want: Read this file: https://raw.githubusercontent.com/intent-driven-dev/openspec-schemas/refs/heads/main/README.md and install schema ."

Included Schemas (6)

Target Audience

Teams using OpenSpec who need a more opinionated workflow for specific delivery types (event-driven services, BDD teams, teams with ADR conventions, Linear shops).

OpenSpec Custom Schemas (intent-driven-dev) — Architecture

Distribution

• Type: standalone-repo (copyable schema folders)
• No CLI binary — schemas are installed manually by copying openspec/schemas/<schema-name>/ into either:
  • Project local: ./openspec/schemas/<schema-name>/
  • User level: $HOME/.openspec/schemas/<schema-name>/
• Activation: set schema: <schema-name> in openspec/config.yaml
• Validation: openspec schema validate

Runtime Requirements

• OpenSpec CLI >= 1.0.0 (npm install -g @fission-ai/openspec@latest)
• Node.js >= 20.19.0 (inherited from OpenSpec CLI)

Repository Directory Structure

openspec/
├── schemas/
│   ├── minimalist/
│   │   ├── README.md
│   │   ├── schema.yaml
│   │   └── templates/
│   ├── event-driven/
│   │   ├── README.md
│   │   ├── schema.yaml
│   │   └── templates/
│   ├── behaviour-driven/
│   │   ├── README.md
│   │   ├── schema.yaml
│   │   └── templates/
│   ├── intent-driven/
│   │   ├── README.md
│   │   ├── schema.yaml
│   │   └── templates/
│   ├── linearized/
│   │   ├── README.md
│   │   ├── schema.yaml
│   │   └── templates/
│   └── spec-driven-with-adr/
│       ├── README.md
│       ├── schema.yaml
│       └── templates/
├── changes/
├── config.yaml
└── specs/

Target AI Tools

Inherits from OpenSpec: all 29+ supported tools (Claude Code, Cursor, Windsurf, Codex, Cline, Gemini CLI, Kiro, Roo, etc.)

Config Integration

# openspec/config.yaml — example for event-driven
schema: event-driven
context: |
  Tech Stack:
    - Node.js + TypeScript
rules:
  event-storming:
    - Focus on payment domain events
  asyncapi:
    - Validate with asyncapi-cli before marking complete

Portability Notes

• Schemas carry no runtime code — they are pure YAML artifact definitions + Markdown templates
• The .codex and .opencode directories in the repo root contain tool-specific skill files for Codex and OpenCode users

OpenSpec Custom Schemas (intent-driven-dev) — Components

Schema Definitions (6)

Each schema is a schema.yaml file defining an artifact graph (ordered DAG of artifact IDs with templates and generation instructions).

Templates

Each schema ships a templates/ directory. Template files correspond 1:1 to artifact IDs:

• spec.md — spec file skeleton with ADDED/MODIFIED/REMOVED sections
• proposal.md — why/what/impact skeleton
• design.md — context/goals/decisions/risks skeleton
• tasks.md — checkbox task list skeleton
• adr.md — Architecture Decision Record skeleton (intent-driven + spec-driven-with-adr only)
• asyncapi.yaml — AsyncAPI spec stub (event-driven only)
• event-storming.md, event-modeling.md — discovery artifacts (event-driven only)

Commands / Skills

None directly provided by this repo. All execution happens via the standard OpenSpec command surface (/opsx:propose, /opsx:apply, etc.).

Codex / OpenCode Integration

• .codex/ directory: skill files for Codex
• .opencode/ directory: skill files for OpenCode

MCP Servers

None.

Scripts

None.

OpenSpec Custom Schemas (intent-driven-dev) — Uniqueness

differs_from_seeds

Closest seed: openspec. This repo is a direct extension of OpenSpec — it uses the same CLI, same command surface, and same openspec/config.yaml activation mechanism. The architectural delta is the introduction of six domain-specific artifact graphs (schemas) that replace OpenSpec's default spec-driven schema. Key additions not in any seed: (1) AsyncAPI specification as a first-class artifact with an enforced external validator gate (asyncapi-cli validate) — the only machine-gated quality check in the OpenSpec ecosystem; (2) Gherkin-style requirement format mandated inside the standard OpenSpec markdown wrapper; (3) ADR persistence at repository top-level adr/ (survives archive cycles); (4) Linear project management integration with MCP-based story binding and archive document mirroring — a project management tool integration not seen in any seed framework.

Positioning

This is the "enterprise delivery methodology pack" for OpenSpec. Where OpenSpec covers the mechanics of spec-driven development, this pack covers domain-specific process standards (BDD, event storming, ADR conventions, PM tool integration). The closest non-OpenSpec seed is kiro which also emphasizes structured artifact sequences, but kiro is a closed IDE and this repo integrates with any OpenSpec-supported tool.

Observable Failure Modes

1. Schema install race: if openspec/config.yaml doesn't exist yet (pre-openspec init), installing a schema fails silently. The README explicitly warns about this but it's easy to hit.
2. asyncapi-cli not installed: the event-driven schema instruction requires asyncapi-cli validate but the tool is not installed by this package. Teams must ensure it's available.
3. Linear MCP unavailability: linearized schema has graceful fallback, but teams who forget to configure Linear MCP lose the story-binding value proposition.
4. ADR drift: the intent-driven schema writes ADRs to <repo>/adr/ which is outside openspec/ — these are not automatically archived or versioned by OpenSpec's archive command.