init: detect and migrate from competitor SDKs

[sentry-junior]

sentry-cli init currently instruments Sentry into a project. It should also detect existing competitor error-monitoring SDKs and optionally migrate the project to Sentry by replacing/removing the competitor integration.

Current behavior

sentry-cli init sets up Sentry SDK integration from scratch. It does not inspect the project for existing error-monitoring tools.

Gap

Projects already using a competitor (e.g. Bugsnag, Rollbar, Airbrake, Honeybadger, AppSignal, Datadog) need manual migration. Automating detection and migration would lower the switching cost and make sentry-cli init a one-stop onboarding path.

Suggested scope

• Detect: scan project files (dependency manifests, config, imports) for known competitor SDKs
• Report: surface what was found and confirm with the user before making changes
• Migrate: remove competitor dependencies/config and replace with equivalent Sentry setup
• Per-ecosystem coverage: start with the highest-value ecosystems (e.g. JavaScript, Python, Ruby) and expand

Prior art

The sentry-for-ai Ruby migration skill already covers detection patterns and migration mappings for AppSignal, Honeybadger, Bugsnag, Rollbar, and Airbrake. This could serve as a reference for the CLI implementation.

Raised by David Cramer.

Action taken on behalf of Miguel Betegon.