docs(skills): add dpdata driver skill

.gitignore

@@ -34,3 +34,7 @@ tests/data_*.h5
 tests/data_*/
 tests/tmp.*
 tests/.coverage
+
+# local dev artifact
+uv.lock
+.venv/

skills/dpdata-driver/SKILL.md

@@ -0,0 +1,144 @@
+---
+name: dpdata-driver
+description: Use dpdata Python Driver plugins to label systems (energies/forces/virials) via System.predict(), list available drivers, and build Driver objects (ase/deepmd/gaussian/sqm/hybrid). Use when working with dpdata Python API (not CLI) and you need driver-based energy/force prediction, plugin registration keys, or examples of using dpdata with ASE calculators or DeePMD models.
+---
+
+# dpdata-driver
+
+Use dpdata “driver plugins” to **label** a `dpdata.System` (predict energies/forces/virials) and obtain a `dpdata.LabeledSystem`.
+
+## Key idea
+
+- A **Driver** converts an unlabeled `System` into a `LabeledSystem` by computing:
+  - `energies` (required)
+  - `forces` (optional but common)
+  - `virials` (optional)
+
+In dpdata, this is exposed as:
+
+- `System.predict(*args, driver="dp", **kwargs) -> LabeledSystem`
+
+`driver` can be:
+
+- a **string key** (plugin name), e.g. `"ase"`, `"dp"`, `"gaussian"`
+- a **Driver object**, e.g. `Driver.get_driver("ase")(...)`
+
+## List supported driver keys (runtime)
+
+When unsure what drivers exist in *this* dpdata version/env, query them at runtime:
+
+```python
+from dpdata.driver import Driver
+
+print(sorted(Driver.get_drivers().keys()))
+```
+
+In the current repo state, keys include:
+
+- `ase`
+- `dp` / `deepmd` / `deepmd-kit`
+- `gaussian`
+- `sqm`
+- `hybrid`
+
+(Exact set depends on dpdata version and installed extras.)
+
+## Minimal workflow
+
+```python
+import dpdata
+from dpdata.system import System
+
+sys = System("input.xyz", fmt="xyz")
+ls = sys.predict(driver="ase", calculator=...)  # returns dpdata.LabeledSystem
+```
+
+### Verify you got a labeled system
+
+```python
+assert "energies" in ls.data
+# optional:
+# assert "forces" in ls.data
+# assert "virials" in ls.data
+```
+
+## Example: use the ASE driver with an ASE calculator (runnable)
+
+This is the easiest *fully runnable* example because it doesn’t require external QM software.
+
+Dependencies (recommended): declare script dependencies with uv inline metadata, then run with `uv run`.
+
+```python
+# /// script
+# requires-python = ">=3.12"
+# dependencies = [
+#   "dpdata",
+#   "numpy",
+#   "ase",
+# ]
+# ///
+```
+
+Script:
+
+```python
+import numpy as np
+from ase.calculators.emt import EMT
+from dpdata.system import System
+
+# write a tiny molecule
+open("tmp.xyz", "w").write("""2\n\nH 0 0 0\nH 0 0 0.74\n""")
+
+sys = System("tmp.xyz", fmt="xyz")
+ls = sys.predict(driver="ase", calculator=EMT())
+
+print("energies", np.array(ls.data["energies"]))
+print("forces shape", np.array(ls.data["forces"]).shape)
+if "virials" in ls.data:
+    print("virials shape", np.array(ls.data["virials"]).shape)
+else:
+    print("virials: <not provided by this driver/calculator>")
+```
+
+## Example: pass a Driver object instead of a string
+
+```python
+from ase.calculators.emt import EMT
+from dpdata.driver import Driver
+from dpdata.system import System
+
+sys = System("tmp.xyz", fmt="xyz")
+ase_driver = Driver.get_driver("ase")(calculator=EMT())
+ls = sys.predict(driver=ase_driver)
+```
+
+## Hybrid driver
+
+Use `driver="hybrid"` to sum energies/forces/virials from multiple drivers.
+
+The `HybridDriver` accepts `drivers=[ ... ]` where each item is either:
+
+- a `Driver` instance
+- a dict like `{"type": "sqm", ...}` (type is the driver key)
+
+Example (structure only; may require external executables):
+
+```python
+from dpdata.driver import Driver
+
+hyb = Driver.get_driver("hybrid")(
+    drivers=[
+        {"type": "sqm", "qm_theory": "DFTB3"},
+        {"type": "dp", "dp": "frozen_model.pb"},
+    ]
+)
+# ls = sys.predict(driver=hyb)
+```
+
+## Notes / gotchas
+
+- Many drivers require extra dependencies or external programs:
+  - `dp` requires `deepmd-kit` + a model file
+  - `gaussian` requires Gaussian and a valid executable (default `g16`)
+  - `sqm` requires AmberTools `sqm`
+- If you just need file format conversion, use the existing **dpdata CLI** skill instead.