Add `ctx.packages` namespace to code mode by manzt · Pull Request #9233 · marimo-team/marimo

manzt · 2026-04-16T18:54:59Z

Code mode's single install_packages() method dispatched to InstallPackagesCommand, which scans the kernel for all other missing modules and re-runs affected cells on success. That's the right default for auto-install on import error, but surprising when an agent is explicitly asking to add one package.

These changes introduces a ctx.packages namespace with add, remove, and list, installed into marimo/_code_mode/_packages.py.

add goes through a custom install loop that keeps the streaming frontend notifications (queued → installing → installed/failed with logs) but drops the missing-module scan and cell re-runs (installing exactly what was asked, nothing more). remove and list are thin wrappers over PackageManager.uninstall / list_packages and update the script metadata for sandboxed notebooks the same way the HTTP endpoints do.

Mutations are queued and flushed on context exit before cell ops, so newly installed packages are importable from cells added in the same batch. list returns the current environment state and raises if add or remove have been queued. The alternative (stale data or silently overlaying pending ops) is worse than a hard error.

async with cm.get_context() as ctx:
    ctx.packages.list()
    ctx.packages.add("pandas", "numpy>=1.26")
    ctx.packages.remove("old-pkg")

Code mode's single `install_packages()` method dispatched to `InstallPackagesCommand`, which scans the kernel for all other missing modules and re-runs affected cells on success. That's the right default for auto-install on import error, but surprising when an agent is explicitly asking to add one package. These changes introduces a `ctx.packages` namespace with `add`, `remove`, and `list`, installed into `marimo/_code_mode/_packages.py`. `add` goes through a custom install loop that keeps the streaming frontend notifications (queued → installing → installed/failed with logs) but drops the missing-module scan and cell re-runs (installing exactly what was asked, nothing more). `remove` and `list` are thin wrappers over `PackageManager.uninstall` / `list_packages` and update the script metadata for sandboxed notebooks the same way the HTTP endpoints do. Mutations are queued and flushed on context exit before cell ops, so newly installed packages are importable from cells added in the same batch. `list` returns the current environment state and raises if `add` or `remove` have been queued. The alternative (stale data or silently overlaying pending ops) is worse than a hard error. async with cm.get_context() as ctx: ctx.packages.list() ctx.packages.add("pandas", "numpy>=1.26") ctx.packages.remove("old-pkg")

vercel · 2026-04-16T18:55:05Z

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Pull request overview

Introduces an explicit ctx.packages namespace in code mode to manage Python packages in a queued/atomic way, avoiding the surprising “scan for other missing modules + rerun cells” behavior when a caller asks to install a specific package.

Changes:

Added marimo/_code_mode/_packages.py implementing queued add, remove, and list operations with streaming install notifications and optional script-metadata updates.
Integrated package-op flushing into AsyncCodeModeContext.__aexit__ (flushed before cell operations) and added AsyncCodeModeContext.packages property.
Updated code-mode context tests to cover ctx.packages behavior (queueing, flushing, list semantics, summary output, etc.).

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 4 comments.

File	Description
`tests/_code_mode/test_context.py`	Replaces `install_packages()` tests with comprehensive coverage for `ctx.packages.{add,remove,list}`.
`marimo/_code_mode/_packages.py`	New implementation of the queued package-ops API with notifications + script-metadata updates.
`marimo/_code_mode/_context.py`	Wires `Packages` into code-mode context lifecycle and summary output; removes `install_packages()`.

Copilot · 2026-04-16T19:00:54Z

+            ctx.packages.remove("old-pkg")
+        """
+        return self._packages
+


install_packages() was removed from AsyncCodeModeContext, but the repo still references it (e.g. scratchpad import-error hint + its test expect ctx.install_packages). This will break those call sites and likely fail the existing test suite. Consider keeping install_packages() as a backwards-compatible alias that delegates to ctx.packages.add(...) (possibly deprecated), or update all remaining references in the same PR.

Suggested change

def install_packages(self, *packages: str) -> None:

"""Backwards-compatible alias for ``ctx.packages.add(...)``.

This preserves older internal call sites that still use

``ctx.install_packages(...)`` after package management moved to

the ``packages`` accessor.

"""

self.packages.add(*packages)

Copilot · 2026-04-16T19:00:54Z

+
+    async def test_remove_single(self, k: Kernel) -> None:


test_add_queued_before_cell_ops only asserts that install was called, not that it happened before the queued cell operations were applied. To actually verify the ordering guarantee, consider tracking both the package install and the kernel cell-execution (e.g., patch the kernel run/execute path) and assert the relative call sequence.

Copilot · 2026-04-16T19:00:54Z

+
+        ops = self._ops
+        self._ops = []
+


The _flush() docstring says it "Returns the ops that ran", but the method can return ops that were never executed (e.g., when there’s no package manager or it isn’t installed). Either adjust the docstring to reflect "ops that were queued/attempted" or change the return value to only include successfully executed ops.

Copilot · 2026-04-16T19:00:55Z

+            return ops
+
+        source: Literal["kernel", "server"] = "kernel"
+        statuses: PackageStatusType = {}
+        for op in ops:


When package_manager is None or the manager binary is missing, _flush() returns ops even though nothing was executed. Since AsyncCodeModeContext uses this return value for the printed summary, this can result in misleading "installed/uninstalled ..." output. Consider returning an empty list here (or returning a separate "attempted" list) so summaries reflect what actually happened.

Pending on marimo-team/marimo#9233 The code mode API for package installation changed from a single `ctx.install_packages()` method to a `ctx.packages` namespace, with `add()` as the install entry point. This brings the docs in line with the current API so examples actually run, and leaves room for related package operations (remove, list) to live under the same namespace. `ctx.install_packages()` still will work (but with deprecation notice).

The previous commit replaced `ctx.install_packages()` with `ctx.packages.add()`, but existing skills and example snippets still reach for the old name. Rather than churn those, this adds a `__getattr__` shim on `AsyncCodeModeContext` that transparently forwards `install_packages` to `packages.add`. `__getattr__` only fires when normal attribute lookup fails, so the name doesn't show up in `dir()` or IDE completion — the new `ctx.packages` namespace remains the discoverable API surface while the legacy call path keeps working silently. Easy to delete once all callers migrate.

manzt · 2026-04-16T19:13:14Z

+        # API. Kept as a hidden shim for in-flight skills / examples;
+        # does not appear in dir() or IDE completion. Prefer
+        # `ctx.packages.add(...)` in new code.
+        if name == "install_packages":


ctx.install_packages is referenced in the skill, so we should probably keep around for a bit: marimo-team/marimo-pair#36

Could use as a hook/nudge to prompt the user to upgrade the skill.

mscolnick · 2026-04-16T19:13:37Z

+    return result
+
+
+class Packages:


probably worth adding the help class here

github-actions · 2026-04-17T13:38:31Z

🚀 Development release published. You may be able to view the changes at https://marimo.app?v=0.23.2-dev47

Copilot AI review requested due to automatic review settings April 16, 2026 18:55

manzt added the enhancement New feature or request label Apr 16, 2026

Copilot started reviewing on behalf of manzt April 16, 2026 18:55 View session

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manzt mentioned this pull request Apr 16, 2026

Update package install API to ctx.packages.add() marimo-team/marimo-pair#36

Merged

manzt force-pushed the push-qrvxrmqploro branch from 40b683e to 3fb4763 Compare April 16, 2026 19:07

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manzt commented Apr 16, 2026

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mscolnick reviewed Apr 16, 2026

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Add help warning message to stderr for legacy API

7672aab

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Fix type-checking

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mscolnick approved these changes Apr 16, 2026

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mscolnick merged commit 9798c58 into main Apr 17, 2026
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mscolnick deleted the push-qrvxrmqploro branch April 17, 2026 13:32

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Add `ctx.packages` namespace to code mode#9233

Add `ctx.packages` namespace to code mode#9233
mscolnick merged 4 commits intomainfrom
push-qrvxrmqploro

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+    def install_packages(self, *packages: str) -> None:
+        """Backwards-compatible alias for ``ctx.packages.add(...)``.
+        This preserves older internal call sites that still use
+        ``ctx.install_packages(...)`` after package management moved to
+        the ``packages`` accessor.
+        """
+        self.packages.add(*packages)

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