ADR 0286: Configured source paths expose registry-derived live references

Status: accepted; extends ADR 0080 and ADR 0102

ADR 0080 introduced ${map.dir} so a later change to [map].dir could not separate the Map from the jobs, Scopes, and Standards that read it. The same drift remained possible for the other authored sources in SOURCE_PATHS: a scope or generator could name discern/skills, for example, while [skills].dir pointed elsewhere.

Treating each path as a new interpolation feature would recreate the duplication that the paths registry removed. It would also leave a future configurable source inert until every consumer learned another hand-written token. The registry already distinguishes stable scalar config paths (resolution = "configured") from values resolved by another rule.

Instruction sources and the setup brief do not have the same shape. [instructions].sources is a list whose concrete seed target is derived from the first non-glob entry; the brief has no live config key. Giving either a scalar-looking reference would conceal that weaker authority.

Every SOURCE_PATHS entry with resolution = "configured" and a non-null config key automatically exposes ${<config-key>}. The current references are ${map.dir}, ${skills.dir}, ${scripts.dir}, and ${project.todo}. SOURCE_PATH_REFERENCES derives their membership and spelling directly from SOURCE_PATHS; no parallel token list is maintained.

expandSourcePathReferences resolves that complete set from the loaded config in every surface that already accepted the scope-glob dialect:

• Scope paths and scope-gate commands.
• Known and custom job commands.
• Generated artifact paths and generator commands.
• Standard commands, inputs, and built-in per extent globs.
• Configured Scope paths used by discern map --export.

Expansion is one simultaneous pass. Unregistered braced forms stay byte-for-byte intact, preserving ordinary shell expansion and leaving this a closed source-path vocabulary rather than a general-purpose config interpolation language.

Fresh-config scope rendering uses the same derived reference for every configured registry member. Whether a directory reference receives a trailing slash follows the entry's registered path shape, not its name. Instruction sources and the fixed brief continue to render their concrete paths; they expose no compatibility token or derived-seed alias.

This decision amends ADR 0080's restriction to the one exact ${map.dir} reference. Its rejection of general-purpose variables remains: the closed set is now the configured scalar subset of SOURCE_PATHS.

Changing [skills].dir, [scripts].dir, [project].todo, or [map].dir keeps every enrolled declaration aligned without rewriting user-owned commands and globs. Fresh configs express live relationships instead of copying defaults.

A new configured source-path registry member enters reference expansion, schema documentation, and the parameterized regression guard automatically. If it belongs to a fresh neutral Scope, that renderer uses the same derived reference. Giving a configured entry no key fails at the registry boundary. The test covers every existing expansion surface with the whole derived set, so a new member cannot work in only one dialect position.

There is still no recursive interpolation and no arbitrary access to discern config. A configured path that happens to contain reference-shaped text remains literal after substitution.

Add ${skills.dir}, ${scripts.dir}, and ${project.todo} individually beside ${map.dir}. Rejected because the next source path would repeat the same omission risk and require another hand-maintained list.

Expose ${instructions.seed} or ${instructions.sources}. Rejected because a list of globs has no single live scalar value, while the seed target is a setup-time derivation rather than its authority.

Expose a brief-path reference. Rejected because the brief is a fixed setup input with no config key. A token would imply that the path can be configured when it cannot.

Allow ${any.config.key}. Rejected because arbitrary interpolation would widen the language beyond source paths, create type-to-string questions, and compete with shell variables.