Design note: updated rad init experience

[zachcasper]

Description

Adds an "In Review" design note (eng/design-notes/cli/2026-08-rad-init-modernization.md)
proposing a modernization of the preview (Radius.*) rad init on-ramp. The command has
accumulated several papercuts that shape a new user's first impression; this note enumerates
each one (backed by a filed issue) and proposes a two-mode experience:

• A zero-question rad init --preview for the common developer case.
• A fully interactive rad init --preview --full for platform engineers.

Proposed changes (documented, not yet implemented)

• Always write a radius-only bicepconfig.json; stop writing app.bicep and stop
  creating the stub application resource.
• Remove the confusing "Setup application in the current directory?" prompt.
• Reorder --full (cluster → cloud providers → environment → recipe pack) and add a
  recipe-pack selection step sourced from defaults.yaml.
• Preserve existing ~/.rad/config.yaml workspaces instead of overwriting the current
  entry when targeting a different cluster.
• Render initialization errors as concise, terminal-safe messages.

Scope

Preview (Radius.*) init path only; the stable (Applications.*) rad init is unchanged.
This is a design proposal, so the PR contains no code changes.

Issues addressed

• No bicepconfig.json created after rad init #12588
• rad init creates an unnecessary stub application resource #12649
• Confusing user prompt on rad init #12587
• Sample app.bicep scaffolded by rad init should define an application resource rather than an application parameter #12418
• Remove AWS Bicep extension from bicepconfig.json scaffolded by rad init #12568
• Malformed error message when Kubernetes namespace does not exist during rad init #12414
• Papercut: rad init overwrites ~/.rad/config.yaml #9177

Dependencies

• Recipe-pack selection depends on Recipe packs should not provision environments resource-types-contrib#296 (recipe-pack
  sources must define only Radius.Core/recipePacks, not an environment).

[radius-functional-tests]

Radius functional test overview

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Click here to see the test run details

Name	Value
Repository	zachcasper/radius
Commit ref	cbedb22
Unique ID	func6cb4da3da7
Image tag	pr-func6cb4da3da7

• Dapr: 1.14.4
• Azure KeyVault CSI driver: 1.4.2
• Azure Workload identity webhook: 1.3.0
• Bicep recipe location ghcr.io/radius-project/dev/test/testrecipes/test-bicep-recipes/<name>:pr-func6cb4da3da7
• Terraform recipe location http://tf-module-server.radius-test-tf-module-server.svc.cluster.local/<name>.zip (in cluster)
• applications-rp test image location: ghcr.io/radius-project/dev/applications-rp:pr-func6cb4da3da7
• dynamic-rp test image location: ghcr.io/radius-project/dev/dynamic-rp:pr-func6cb4da3da7
• controller test image location: ghcr.io/radius-project/dev/controller:pr-func6cb4da3da7
• ucp test image location: ghcr.io/radius-project/dev/ucpd:pr-func6cb4da3da7
• deployment-engine test image location: ghcr.io/radius-project/deployment-engine:latest

Test Status

⌛ Building Radius and pushing container images for functional tests...
✅ Container images build succeeded
⌛ Publishing Bicep Recipes for functional tests...
✅ Recipe publishing succeeded
⌛ Starting corerp-cloud functional tests...
⌛ Starting ucp-cloud functional tests...
✅ ucp-cloud functional tests succeeded
❌ corerp-cloud functional test failed. Please check the logs for more details

[github-actions]

Functional Tests - corerp-cloud

30 tests  ±0   27 ✅  - 2   20m 25s ⏱️ - 3m 40s
 2 suites ±0    1 💤 ±0 
 1 files   ±0    2 ❌ +2 

For more details on these failures, see this check.

Results for commit cbedb22. ± Comparison against base commit aeb5292.