Polylith Sync

Sync Skill

💡 Terminology: this skill uses Polylith terms like brick, project, and development project. If they're unfamiliar, load polylith-concepts first.

Quick command

uv run poly sync --quiet

⚠ Agents must pass --quiet. poly sync has an interactive mode that will prompt on stdin and hang the process if no human is attached. --quiet suppresses output and disables the interactive prompts. Never use --verbose in an agent run — it is the opposite of --quiet and can trigger interactive mode. Save --verbose for humans who are debugging at a terminal.

Command prefix: If you do not know the package manager, list lock files with ls uv.lock poetry.lock pdm.lock 2>/dev/null (a pyproject.toml is always present, so it tells you nothing on its own). Use uv run poly (uv), poetry poly (poetry), pdm run poly (pdm), hatch run poly (hatch), or poly (activated venv). Examples below use uv run.

When to run

• After poly create base / poly create component — registers the new brick in the development project.
• After poly create project — only if the interactive prompt was skipped.
• After adding a new import between bricks — picks up the transitively pulled-in brick.
• Before poly check and before any release/CI run.

⚠ poly sync adds missing bricks but does not remove unused ones. Stale entries in [tool.polylith.bricks] must be deleted by hand. It also does not sync third-party libraries — use poly libs / poly check for those.

What it does

• Per project under projects/: resolves the project's base(s), walks the import graph, and adds any imported brick missing from [tool.polylith.bricks].
• For the development project (root pyproject.toml): always lists every base and every component in the workspace.

Command reference

Examples

# Agent / CI default — non-interactive, no output
uv run poly sync --quiet

# Agent: only one project, still non-interactive
uv run poly sync --quiet --directory projects/user_api

# Human, at a terminal: verbose for debugging missing bricks (may prompt!)
uv run poly sync --verbose

Output

Nothing changed:

✔ project-a
✔ project-b
✔ development

A brick was added:

👉 the-cli
adding greeting component to the-cli

Notes for the agent

• Always run with --quiet. Without it, poly sync may drop into an interactive prompt and hang the process — agents cannot answer stdin prompts. Never combine with --verbose, which leans the other way and can trigger interactive mode.
• The exit code is always 0 — poly sync is informational, not a gate. For a CI gate, follow it with poly check (load polylith-check).
• If a brick is showing up in unexpected projects after sync, it's because something the project's base imports (transitively) imports that brick. Trace it with poly deps --brick <name> (load polylith-dependency-visualization).
• Git reminder: If poly sync adds missing bricks to any pyproject.toml files, use your git tools to review the diff and ensure those changes are committed. Because --quiet suppresses output, the agent should rely on git diff (or re-run poly info) to confirm what changed.

Background — the development project

The root pyproject.toml doubles as a "development project": a single virtual environment that includes every brick and every dependency (production and dev-only). The development/ directory holds REPL scripts and notebooks that import bricks freely. poly sync keeps the development project complete by listing every brick in the workspace there. Per-project pyproject.tomls under projects/ only list the bricks each project actually uses.

Verification

After running poly sync, verify the changes by inspecting the [tool.polylith.bricks] section in the relevant projects/<name>/pyproject.toml or the root pyproject.toml to ensure the new bricks were added. Alternatively, run poly info (load polylith-workspace-inspection) to see the updated matrix.