# Which Problems Are Solved
As part of https://github.com/zitadel/zitadel/issues/11917 we want to
introduce error slugs so (API) clients can rely on stable,
machine-readable errors and act accordingly.
# How the Problems Are Solved
- Added a `NewSlug` helper function in the domain package.
- Added `ErrorDetails` to the `ZitadelError`
- Added an `zitadel.error.v2.ErrorDetail` proto message
- Updated the connectRPC error interceptor to map new slug based errors
to the new `ErrorDetail`
- Defined some common slugs and error functions like internal errors
- Defined (session) specific slugs used in the `DeleteSession` and
`CheckUser` functions and replaced old implementations
- Updated integration tests to check specific errors if the relation
database feature is enabled
- Updated doc and guideline to reflect the latest changes and decisions
- Updated DeleteSession endpoint API to list possible slugs
# Additional Changes
None
# Additional Context
- closes#11957
---------
Co-authored-by: Wim Van Laer <[email protected]>
## Todos for release
- [x] Configure Env in docs project on vercel
- [x] Configure Root Path in the docs project on vercel
- [ ] Remove old CSP https://github.com/zitadel/website/pull/1592
## What we did
This pull request migrates the project documentation from the old
`docs/` directory to the new `apps/docs/` directory, introduces a new
documentation system built with Next.js and Fumadocs, and updates all
relevant references, configuration files, and documentation to reflect
this change. It also adds new configuration and ignore files for the new
documentation app, updates CI and linting to exclude the new docs from
certain checks, and revises the contributing guidelines accordingly.
**Documentation System Migration and New Docs App**
* Migrated all documentation from `docs/` to `apps/docs/`, and updated
all references in `README.md`, `CONTRIBUTING.md`, and other files to
point to the new location.
[[1]](diffhunk://#diff-eca12c0a30e25b4b46522ebf89465a03ba72a03f540796c979137931d8f92055L585-L640)
[[2]](diffhunk://#diff-eca12c0a30e25b4b46522ebf89465a03ba72a03f540796c979137931d8f92055L660-R607)
[[3]](diffhunk://#diff-eca12c0a30e25b4b46522ebf89465a03ba72a03f540796c979137931d8f92055L740-R687)
[[4]](diffhunk://#diff-b335630551682c19a781afebcf4d07bf978fb1f8ac04c6bf87428ed5106870f5L2-R3)
[[5]](diffhunk://#diff-b335630551682c19a781afebcf4d07bf978fb1f8ac04c6bf87428ed5106870f5L30-R30)
* Added a new Next.js/Fumadocs-based documentation app under
`apps/docs/`, including core app files, layouts, routing, search API,
and a comprehensive `README.md` with development and contribution
instructions.
[[1]](diffhunk://#diff-5a1b07344a2c1b4d3f37b23ff1388b62cd9f57dea3c1cd23d8a0412b7602b132R1-R74)
[[2]](diffhunk://#diff-462b9ad1eabbb7d1c29bb9c36e4931eb180fd7190900e6d2babf8f4d66ad1c28R1-R39)
[[3]](diffhunk://#diff-e16ae25660ded787b10ac35dea96d5ecaacf895dae0afc8a9bd4382dc79a8c87R1-R7)
[apps/docs/app/[[...slug]]/layout.tsxR1-R81](diffhunk://#diff-59e08acde4e805b7aeccef1dcf98f1d71dfc550777e6b9402085cee0e9fa4e0aR1-R81),
[apps/docs/app/[[...slug]]/page.tsxR1-R79](diffhunk://#diff-e5df3f80d0fa01e12d63d81f29c57a9d14e846c78fd3beabb2ef768e38fd9580R1-R79),
[[4]](diffhunk://#diff-389b34918e040cacaa87cd7201ffa462cc2b0b716736f537e3d3c660ac69353bR1-R7)
[[5]](diffhunk://#diff-d3b03416d1c457b19f1c27b26f2db741412df841b875c26ccadc36e4522247f4R1-R29)
[[6]](diffhunk://#diff-c8fb8339570a5305809be7c618e14705fd86390dc278e6ce8ba224a7bc8b0c3cR1-R25)
**Configuration and Tooling Updates**
* Updated `.github/workflows/codeql.yml`, `.golangci.yaml`, and
`.github/dependabot.yml` to properly handle the new docs app: excluded
`apps/docs` from certain checks, added npm dependency updates for the
docs app, and excluded generated content.
[[1]](diffhunk://#diff-12783128521e452af0cfac94b99b8d250413c516ec71fe6d97dbea666ff7ba27L8-R14)
[[2]](diffhunk://#diff-9917ddc9f1c3304218f7269265b746d997c5c0615478177b5fceecd33ef47cb5R5-R6)
[[3]](diffhunk://#diff-9917ddc9f1c3304218f7269265b746d997c5c0615478177b5fceecd33ef47cb5R126-R129)
[[4]](diffhunk://#diff-dd4fbda47e51f1e35defb9275a9cd9c212ecde0b870cba89ddaaae65c5f3cd28R89-R106)
* Updated `.devcontainer/devcontainer.json` to use the latest Go 1.25.3
version for consistency.
**Licensing and Miscellaneous**
* Added `apps/docs/` to the list of licensed directories in
`LICENSING.md`.
These changes ensure the documentation is now maintained in a modern,
scalable system and all project tooling is updated to support the new
structure.
---------
Co-authored-by: Federico Coppede <[email protected]>