Build an extension

Start with a workspace .phonton directory:

.phonton/
  skills/
    review-gate/
      skill.toml
      SKILL.md
  steering.toml
  profiles.toml

Create these files directly in the workspace. The v0.19.0 CLI inspects local records but does not expose a scaffold command.

Add a skill

[skill]
id = "review-gate"
name = "Review Gate"
version = "0.1.1"
entry = "SKILL.md"
trust = "text-only"
recommended_verify = ["phonton review latest"]

SKILL.md should be short and operational. It should tell Phonton how to handle a class of work, not replace project documentation.

Add steering rules

[[rules]]
id = "review-gate.verification-output"
name = "Verification output"
severity = "fail"
text = "A completed change must report which verification commands ran."

Severity options:

Severity	Meaning
advise	Prompt guidance only.
warn	Make ambiguity visible.
fail	Verification should fail when a violation is detectable.

Add a profile

[[profiles]]
id = "review-gate"
name = "Review Gate"
activates = ["review-gate", "review-gate.verification-output"]
max_tokens = 120000

Profiles are activation bundles. They help teams switch between extension sets without hiding which records influenced the run.

Verify the pack

phonton extensions doctor
phonton extensions list --json
phonton plan "make a small, verifiable change"