How customization works

Open this when the user asks where an override goes, how it merges, why it is not applied, or how to change central config. To change one skill or agent, recommend bmad-customize. For team-wide rules see help/team-adoption.md.

The layers for one skill

A skill is customizable only if its folder holds a customize.toml, which lists every field that can change. Updates overwrite it, so nobody edits it. Overrides live in {project-root}/_bmad/custom/, named after the skill folder.

bmad setup writes _bmad/custom/.gitignore with *.user.toml when none exists.

Merge rules

The value's shape decides the merge. The field name does not.

Limits

• An override cannot remove a shipped item. Replace a keyed item with one that does nothing.
• It cannot change step logic or any field customize.toml does not list. Never invent a field. Offer activation_steps_prepend, activation_steps_append or persistent_facts instead, or a feature request.
• On an agent skill, agent.name and agent.title are metadata. Overriding them does nothing.
• Write only the changed fields. A full copy of customize.toml blocks later shipped defaults.

Agent or workflow

The top table in customize.toml is [agent] or [workflow]. Override fields go under the same table. A rule for every workflow an agent runs goes on the agent skill: persona, style, principles, facts, menu. A rule for one workflow goes on that workflow skill: templates, output paths, on_complete, step hooks.

Central config

It holds [core] values such as output_folder, module answers under [modules.<code>], and optional [agents.<code>] tables that add an agent of the user's own or add details such as team to an installed one. An installed agent's name, title, and icon come from its own skill and its override file, not from here. Three files merge by the same rules, highest first:

1. _bmad/custom/config.user.toml: personal. bmad setup writes user answers here. Not committed.
2. _bmad/custom/config.toml: team pins. Written by hand only. Committed.
3. _bmad/config.toml: created by bmad setup, which writes team answers here.

All three may be hand-edited. bmad setup never changes an existing value, so to change an answer, edit its key in the file bmad setup reports for it. bmad-customize does not write central config: help the user edit the TOML.

Check the merged result

bmad-customize shows the merged result after it writes. _bmad/scripts/resolve_customization.py (one skill) and resolve_config.py (central config) print the merged values as JSON. If a script is missing, recommend bmad setup.

An override is not applied

1. The file is in _bmad/custom/ and named exactly after the skill folder.
2. The TOML parses. The resolver errors and names a broken file.
3. Fields sit under [agent] or [workflow] and exist in customize.toml.
4. The shape matches, and a replaced item uses the same code or id.
5. No user file overrides the team value.
6. uv runs. Without the resolver, many skills use shipped defaults.

Reset

Delete the override file, or the one field. The skill uses shipped defaults on its next run.