[jamesbxwu]

agentbricks tracing get currently prints an MLflow warning before the CLI error, breaking the JSON error stream. Suppressing that warning through the fluent API also hides permission and service failures as missing traces.

Read through the public MlflowClient.get_trace(display=False) API, which preserves exceptions. Only typed not-found errors receive the short missing-trace message; invalid IDs, permission errors, and service failures retain their details and error codes in structured CLI output. Carry the selected experiment's UC destination into retrieval, preserve the warehouse context, and leave already-qualified trace IDs unchanged.

Fixes ML-69250.

Validation:

• 74 focused tracing/runtime tests pass with installed MLflow 3.16.1 and again with cached MLflow 3.10.1 client sources. The latter uses a source overlay, with an expected warning about the installed full-package metadata version.
• Regressions exercise the real public client error path through the registered CLI in text and JSON modes, including invalid IDs, missing traces, permission denial, and service errors. UC-routing cases cover plain and qualified IDs.
• Ruff, formatting, focused type checks, and diff checks pass. No dependencies changed.

The earlier read-only DEFAULT checks predate this review follow-up; no new live requests were made. Public CI has been retriggered for the new head. The six memory-backed parallel-history ordering failures seen in earlier framework CI also reproduce on main.

Combined follow-up validation

Test-only source 7b6e3ac407a42acc0b86874b9e36ccb8639d0167 combines the twelve bug-bash PRs and these review follow-ups. The Agent Bricks unit suite passed 2,194 tests, 24 skipped in 60.46s; combined Ruff and formatting checks pass. The README conflict was resolved by retaining the guide split and placing the new auth guidance in Authentication. This combined branch is for testing and must not be merged into main. Historical live runs predate the review fixes; no fresh live acceptance is claimed.

Current public CI: 53 green, 1 red. The framework job fails only the same six memory-backed parallel-history ordering cases already reproduced on main. No skips were applied.