env-management
Environment and package management
The notebook runs against the session's bound runtime: the app-managed default (default-python / default-r) unless you bind another one with notebook_bind_runtime — a named environment you created, or one of the user's own detected interpreters. You never activate environments by hand, and you never install packages from inside a cell. Installs happen in the trusted main process through a single tool, manage_packages, and always land in the currently bound runtime. This page is the workflow for getting a package installed and for knowing when a package is not something you can install yourself.
When a package is missing
A run that fails with ImportError / ModuleNotFoundError (Python) or Error in library(x): there is no package called 'x' (R) means the package is not in the environment yet. The fix is one manage_packages call, not a code change. Do not rewrite the cell to use a different library that "does roughly the same thing" — install the package the task actually needs. Do not fall back to reading data or computing results a worse way to dodge the missing import.
Check an installed version
Use inspect_packages(language, packages) when the user asks whether a package is installed in an app-managed runtime or which version is present, or when your code depends on a version-specific feature. It reads package metadata from the session's bound app-managed runtime without importing the package or changing the environment. An installed result does not prove the import will succeed; use notebook_execute when importability itself is the question.
Inspection does not provision a missing app-managed default runtime. If it reports DEFAULT_RUNTIME_NOT_READY, use notebook_execute in that language to prepare the runtime under notebook execution approval, then retry inspect_packages.
inspect_packages intentionally rejects a user-owned external runtime because reading its metadata executes that interpreter. Use notebook_execute for an external runtime so the user sees the normal notebook execution approval.
Do not use inspection as a mandatory preflight for every install. For a clear missing-package error, call manage_packages directly; installation is the recovery action, while inspection is for explicit version and compatibility questions.