Customizing SDD

You never edit the shipped skills. Every phase skill starts by loading settings, and those settings live in your project — or your home directory — so they survive updates:

flowchart LR
    P["project .sdd/"] -->|missing?| G["global ~/.sdd/"] -->|missing?| S["shipped defaults"]

The first one that has a file wins, and missing files are normal: with no .sdd/ at all, everything runs on the defaults below. ./install.sh --init writes a commented .sdd/ to start from.

`.sdd/config.yaml`

Key	Default	Effect
`specs_dir`	`specs`	Where feature folders and `constitution.md` live
`language`	`en`	Language of every generated artifact
`ids.requirement` / `ids.task`	`REQ` / `T`	ID prefixes (`REQ-1`, `T-1`)
`gates`	`[specify, plan, tasks]`	Phases that stop for your approval. `[]` runs the cycle autonomously
`verify_command`	`""`	The command that counts as evidence. Empty: the constitution’s test command, else the agent asks
`phases`	`[constitution, specify, plan, tasks, implement, verify]`	The order routing walks. Add your own phases here

Templates and rules

Templates. Copy a shipped template (spec.md, plan.md, tasks.md, verify.md, constitution.md) to .sdd/templates/ and edit it. Keep the REQ-n / T-n structure: the other phases read it.
Rules. .sdd/rules/all.md adds rules to every phase; .sdd/rules/<phase>.md to one. They add to the skill and win where they conflict with it. Short, checkable bullets work best — for example, the example folder’s rules/specify.md makes every spec carry a Security section, and the worked example in the repository has one because of it.

Your own phases

Copy templates/my-phase to a folder named after your phase (say sdd-adr), say what it reads and the one file it writes in the feature folder, install it next to the others, and add it to phases::

phases: [constitution, specify, adr, plan, tasks, implement, verify]

Routing walks phases in order and stops at the first phase that is not done, so an ADR step between specify and plan runs before planning, and sdd-plan reads the ADR it left.

The extending guide has three complete recipes: a security section in every spec, artifacts in Spanish, and an ADR phase.