prizm

One def in, every harness out.

prizm is a single-file, pure-bash transpiler that turns unified TOML definitions into native agents, skills, and slash commands for four LLM coding harnesses:

Harness	Agents	Skills	Commands
Claude Code	claude/agents/*.md	claude/skills/*/SKILL.md	claude/commands/*.md
Gemini CLI	gemini/agents/*.md	gemini/skills/*/SKILL.md	gemini/commands/*.toml
opencode	opencode/agents/*.md	opencode/skills/*/SKILL.md	opencode/commands/*.md
Codex CLI	codex/agents/*.toml	codex/skills/*/SKILL.md	codex/prompts/*.md ¹

¹ Codex prompts are deprecated; set emit = "skill" in the [codex] table to ship a skill instead.

Each harness invented its own frontmatter, field names, argument syntax, and directory layout. Writing the same agent four times means it drifts four ways. With prizm you author one defs/<name>.<kind>.toml and the build emits every native format, verified against each harness's official docs.

Quick start

cp defs/_template.skill.toml defs/my-skill.skill.toml
$EDITOR defs/my-skill.skill.toml
./prizm                      # build everything (or: ./prizm defs/my-skill.skill.toml)

The artifact's name and kind come from the file name. Requires bash 4+, nothing else.

The def language

A TOML subset with one shared body (the prompt) plus a [claude] / [gemini] / [opencode] / [codex] table per harness holding that harness's fields under their real native names. Portable body syntax is rewritten per harness:

• $ARGUMENTS and 1-based $1..$9 — positional args (Claude's 0-based convention handled automatically)
• !`cmd` — inline shell where supported, a bracketed run-this-command instruction where not
• <!-- only: claude, gemini --> … <!-- /only --> — body section for listed harnesses only

Escape hatches: raw = '''…''' injects verbatim metadata (nested permission maps, hooks, extra tables), body = '''…''' overrides the shared body per harness. Anything unparseable is a hard build error: prizm never emits a mangled value.

The full language reference lives in the header comment of prizm; the defs/_template.*.toml files enumerate every documented field of every harness.

Layout

• defs/ — the source of truth: your defs plus _template.*.toml (all-fields-documented, skipped by the build)
• prizm — the transpiler
• claude/, gemini/, opencode/, codex/ — build output, gitignored; never edit by hand