specfirst

Spec-first spec-driven development for Claude Code and OpenCode: a durable per-initiative spec document (ROADMAP.md, cavekit-style sections, no symbol table) plus a right-sized, subagent-driven build pipeline.

Install

Claude Code

/plugin marketplace add MartyBeGood/specfirst
/plugin install sf@specfirst

OpenCode

From git:

{
  "plugin": ["specfirst@git+https://github.com/MartyBeGood/specfirst.git"]
}

OpenCode installs it with Bun at startup. Pin a branch/tag with #<ref>. For a local checkout (development, symlinked plugin), tool mapping, and troubleshooting, see .opencode/INSTALL.md.

Restart OpenCode after any install change.

Use

1. /sf:spec <idea> — creates .specfirst/build/<slug>/ROADMAP.md, the initiative's spec (goal, constraints, interfaces, invariants, tasks).
2. /sf:build --next — executes the next §T task: trivial tasks run natively, tasks that cite a §V/§I item (or turn out to touch more than one file) get the full implementer + reviewer + fix-loop pipeline.
3. /sf:check — read-only drift report: does the code still match the spec's invariants and interfaces?

Four optional commands sit around this core loop: /sf:grill sharpens a fuzzy idea before spec, /sf:research gathers external facts into §R, /sf:review adversarially reviews the spec before build, /sf:deepen spends spare budget improving a module's design. Each drafts content and hands it to /sf:spec to write.

See docs/FORMAT.md for the full spec document format, and docs/superpowers/specs/2026-08-21-specfirst-design.md for the design this was built from. OpenCode differences (command names, tool mapping) are in .opencode/INSTALL.md; the port's design is in docs/superpowers/specs/2026-08-21-opencode-support-design.md.