Add AI assistant skills for DQX

.claude-plugin/marketplace.json

@@ -0,0 +1,15 @@
+{
+  "name": "databrickslabs-dqx",
+  "owner": {
+    "name": "Databricks Labs",
+    "email": "labs@databricks.com",
+    "url": "https://databrickslabs.github.io/"
+  },
+  "plugins": [
+    {
+      "name": "dqx",
+      "source": "./skills",
+      "description": "DQX by Databricks Labs — AI assistant skills for defining, applying, storing, and profiling data quality rules in PySpark."
+    }
+  ]
+}

.github/pull_request_template.md

@@ -20,3 +20,4 @@ Resolves #..
 
 - [ ] added/updated demos
 - [ ] added/updated docs
+- [ ] added/updated agent skills

docs/dqx/docs/dev/contributing.mdx

@@ -529,3 +529,24 @@ print("Hello, world!")
 ```
 ````
 </Admonition>
+
+## Updating AI Assistant Skills
+
+DQX ships agent skills under [`skills/`](https://github.com/databrickslabs/dqx/tree/main/skills) that teach AI assistants (Databricks Genie Code, Claude Code, etc.) how to use the public DQX API. Changes to DQX's public APIs must be reflected in the matching skill.
+
+The following skills are provided to cover the main capabilities of DQX:
+
+| Skill                                      | When to update                                                                                                                        |
+|--------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------|
+| `skills/dqx-define-checks/SKILL.md`        | Adding / changing rule classes (`DQRowRule`, `DQDatasetRule`, `DQForEachColRule`), `check_funcs`, or the YAML / dict metadata schema. |
+| `skills/dqx-apply-checks/SKILL.md`         | Adding / changing any `DQEngine.apply_checks*` method or its result-column shape.                                                     |
+| `skills/dqx-end-to-end/SKILL.md`           | Changes to `apply_checks_and_save_in_table*`, `InputConfig` / `OutputConfig`, or `RunConfig`-based execution.                         |
+| `skills/dqx-profile-and-generate/SKILL.md` | Changes to `DQProfiler` / `DQGenerator` / `DQDltGenerator` or their options.                                                          |
+| `skills/dqx-storage/SKILL.md`              | Adding / changing any `*ChecksStorageConfig` or the `DQEngine.{load,save}_checks` API.                                                |
+
+### Guidelines for Updating Skills
+
+- Keep each `SKILL.md` file short. The full file is loaded into context when a skill fires.
+- Link to existing documentation instead of duplicating content. The skill's job is to tell the assistant when and how to use an API.
+- Limit skills to use only public methods and APIs of DQX.
+- Update the [documentation](https://github.com/databrickslabs/dqx/blob/v0.13.0/docs/dqx/docs/guide/ai_tools_skills.mdx) if you change install paths, the marketplace manifest, or the public list of skills.

docs/dqx/docs/guide/ai_tools_skills.mdx

@@ -0,0 +1,118 @@
+---
+sidebar_position: 314
+---
+
+import Admonition from '@theme/Admonition';
+import Tabs from '@theme/Tabs';
+import TabItem from '@theme/TabItem';
+
+# AI Tools & Skills
+
+DQX ships [Agent Skills](https://agentskills.io/) that teach AI assistants how to use the library correctly. They're small, focused Markdown files with YAML frontmatter — the open format supported by [Databricks Genie Code](https://docs.databricks.com/aws/en/genie-code/skills), [Claude Code](https://docs.claude.com/en/docs/claude-code/plugins), and any other tool that follows the standard.
+
+The skills live in the [`skills/`](https://github.com/databrickslabs/dqx/tree/main/skills) directory of the DQX repo.
+
+## What's included
+
+| Skill                      | What it covers                                                                                       | Canonical docs                                                                                |
+|----------------------------|------------------------------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------------|
+| `dqx-define-checks`        | Creating quality rules — `DQRowRule`, `DQDatasetRule`, `DQForEachColRule`, YAML / dict metadata form | [Quality Checks Definition](/docs/guide/quality_checks_definition)                            |
+| `dqx-apply-checks`         | Validating a DataFrame or table against a set of rules                                               | [Applying Quality Checks](/docs/guide/quality_checks_apply)                                   |
+| `dqx-end-to-end`           | Read → check → write in one call with `apply_checks_and_save_in_table`                               | [End-to-end apply](/docs/guide/quality_checks_apply#applying-checks-defined-with-dqx-classes) |
+| `dqx-profile-and-generate` | Profiling and generating rule candidates with `DQProfiler` / `DQGenerator`                           | [Data Profiling](/docs/guide/data_profiling)                                                  |
+| `dqx-storage`              | Loading / saving checks across file, workspace, volume, table, installation, and Lakebase backends   | [Loading and Storing Quality Checks](/docs/guide/quality_checks_storage)                      |
+
+Each skill is a folder containing a single `SKILL.md` with the standard `name` + `description` frontmatter. Tools auto-load skills based on the description; users can also invoke them explicitly (`@dqx-define-checks`, slash commands, etc.) depending on the tool.
+
+## Installing DQX skills
+
+<Tabs>
+<TabItem value="genie" label="Databricks Genie Code" default>
+
+Clone the DQX repository in your workspace using a [Git folder](https://docs.databricks.com/aws/en/repos/git-operations-with-repos), 
+then copy the `skills/` folder into a workspace-level or user-level skills directory:
+
+```bash
+# Option A — workspace-wide (all Genie Code users see these)
+databricks workspace import-dir skills /Workspace/.assistant/skills
+
+# Option B — current user only — substitute your workspace email below
+databricks workspace import-dir skills /Users/<your-email>/.assistant/skills
+```
+
+Genie Code picks up skills from these directories automatically. Use the following prompt with Agent mode to confirm:
+
+> *"List the DQX skills you can use."*
+
+The skill fires when its description matches your request. Use `@` to manually invoke a specific skill (e.g. `@dqx-define-checks add a uniqueness check on order_id`).
+
+See the [Databricks Genie Code Documentation](https://docs.databricks.com/aws/en/genie-code/skills) for more details.
+
+</TabItem>
+<TabItem value="claude" label="Claude Code">
+
+The DQX repo is a Claude Code plugin marketplace ([`.claude-plugin/marketplace.json`](https://github.com/databrickslabs/dqx/blob/v0.13.0/.claude-plugin/marketplace.json) at the repo root) containing the `dqx` plugin under [`skills/`](https://github.com/databrickslabs/dqx/tree/main/skills). Add the marketplace once, then install:
+
+```bash
+# Inside Claude Code
+/plugin marketplace add databrickslabs/dqx
+/plugin install dqx@databrickslabs-dqx
+```
+
+Or drop the folder into your personal skills directory for a one-off install:
+
+```bash
+cp -R skills/dqx-* ~/.claude/skills/
+```
+
+Each skill becomes available as `/dqx:dqx-define-checks` (plugin-installed) or as a normal skill (user-level). Claude auto-invokes on description match.
+
+See the [Claude Code Plugins documentation](https://docs.claude.com/en/docs/claude-code/plugins) for more details.
+
+</TabItem>
+<TabItem value="other" label="Other AI dev tools">
+
+Any tool that follows the [Agent Skills](https://agentskills.io/) open standard can install and load DQX skills. To install DQX skills with your tool:
+
+1. Copy the per-skill folder into the tool's configured skills directory.
+2. Make sure the path contains `SKILL.md` directly (not nested one level deeper).
+3. Restart the tool if it caches on startup.
+
+<Admonition type="note" title="Flattening skill files">
+If your tool expects a single flat skills file instead of a directory with multiple files, concatenate the files:
+
+```bash
+cat skills/dqx-*/SKILL.md > dqx-skills.md
+```
+</Admonition>
+</TabItem>
+</Tabs>
+
+## Using DQX skills
+
+After installing DQX skills, you can either let your tool use skills automatically or invoke them by name. Typical prompts:
+
+```
+Add a DQX uniqueness check on (order_id, line_item_id) to my pipeline.
+Split my bronze table into valid and quarantine outputs using these rules: …
+Profile catalog.schema.orders and suggest quality checks.
+Load DQX checks from a Delta table and apply them to a streaming DataFrame.
+```
+
+Agents will load the relevant skill into context, follow its patterns, and link back to the canonical documentation for anything outside the skill's scope.
+
+## Extending DQX skills
+
+DQX's agent skills are scoped to DQX's public APIs. Follow these guidelines when extending them:
+
+- Skills should stay short; the full `SKILL.md` is loaded every time the skill fires, so every line costs tokens on every invocation.
+- Prefer linking to `/docs/...` over duplicating content; the skill's job is to tell the model **when** and **how** to use the API, not to reprint the reference.
+- Always import from `databricks.labs.dqx.*` — never guess module paths.
+- Point to the canonical documentation for any topic outside the skill's core responsibility.
+- Changes to the public DQX API should be reflected in the matching skill in the same PR. See [Contributing](/docs/dev/contributing) for the full workflow.
+
+## Source
+
+- Skills: [`skills/`](https://github.com/databrickslabs/dqx/tree/main/skills)
+- Plugin manifest (Claude Code / generic): [`skills/.claude-plugin/plugin.json`](https://github.com/databrickslabs/dqx/blob/v0.13.0/skills/.claude-plugin/plugin.json)
+- Marketplace manifest (Claude Code): [`.claude-plugin/marketplace.json`](https://github.com/databrickslabs/dqx/blob/v0.13.0/.claude-plugin/marketplace.json)

skills/.claude-plugin/plugin.json

@@ -0,0 +1,27 @@
+{
+  "name": "dqx",
+  "version": "0.1.0",
+  "description": "DQX by Databricks Labs — AI assistant skills for defining, applying, storing, and profiling data quality rules in PySpark.",
+  "author": {
+    "name": "Databricks Labs",
+    "email": "labs@databricks.com"
+  },
+  "homepage": "https://databrickslabs.github.io/dqx/",
+  "repository": "https://github.com/databrickslabs/dqx.git",
+  "license": "SEE LICENSE IN LICENSE",
+  "keywords": [
+    "databricks",
+    "dqx",
+    "data-quality",
+    "pyspark",
+    "delta",
+    "unity-catalog"
+  ],
+  "skills": [
+    "./dqx-define-checks",
+    "./dqx-apply-checks",
+    "./dqx-end-to-end",
+    "./dqx-profile-and-generate",
+    "./dqx-storage"
+  ]
+}

skills/README.md

@@ -0,0 +1,23 @@
+# DQX AI Assistant Skills
+
+DQX provides agent skills that can be used with [Databricks Genie Code](https://docs.databricks.com/aws/en/genie-code/skills) or any tool that follows the [Agent Skills](https://agentskills.io/) open standard. Skills teach AI assistants how to use DQX.
+
+## Skills
+
+Each skill is a folder with a `SKILL.md` file that documents usage patterns. The following skills are available:
+
+| Skill                                                                 | What it covers                                                                                                          |
+|-----------------------------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------|
+| [`dqx-define-checks`](./dqx-define-checks/SKILL.md)                   | Creating quality rules (`DQRowRule`, `DQDatasetRule`, `DQForEachColRule`) and the equivalent YAML / dict metadata form. |
+| [`dqx-apply-checks`](./dqx-apply-checks/SKILL.md)                     | Validating data with a set of rules (checks loadable from YAML / JSON / Delta).                                         |
+| [`dqx-end-to-end`](./dqx-end-to-end/SKILL.md)                         | Running check → save cycles in one call with `apply_checks_and_save_in_table`.                                          |
+| [`dqx-profile-and-generate`](./dqx-profile-and-generate/SKILL.md)     | Profiling a dataset and generating rule candidates with `DQProfiler` / `DQGenerator`.                                   |
+| [`dqx-storage`](./dqx-storage/SKILL.md)                               | Loading and saving checks across file / workspace / volume / table / installation / Lakebase backends.                  |
+
+## Install
+
+See the [installation and usage guide](https://databrickslabs.github.io/dqx/docs/guide/ai_tools_skills) for Databricks Genie Code and other AI tools.
+
+## Scope and guardrails
+
+DQX's agent skills are scoped to DQX's public APIs. See [Extending DQX skills](https://databrickslabs.github.io/dqx/docs/guide/ai_tools_skills#extending-dqx-skills) on the docs site for the full list of design guidelines.

skills/dqx-apply-checks/SKILL.md

@@ -0,0 +1,103 @@
+---
+name: dqx-apply-checks
+description: >
+  Validate a PySpark DataFrame or Delta table against a set of DQX quality rules using
+  DQEngine. Use when the user asks to "run data quality checks", "apply DQX rules to a
+  DataFrame/table", "split valid and invalid rows", "quarantine bad records", or
+  "integrate DQX into a streaming pipeline". Covers apply_checks, apply_checks_and_split,
+  the by_metadata variants, and the shape of the result columns.
+---
+
+# DQX — Apply quality checks
+
+Apply checks with `DQEngine`. There are six method families — pick by **(1) rule form** and **(2) what output you want**.
+
+| Rule form                                                                      | Append results as columns  | Split valid / invalid                 | End-to-end (read + check + write)            |
+|--------------------------------------------------------------------------------|----------------------------|---------------------------------------|----------------------------------------------|
+| Classes (`DQRowRule`, …)                                                       | `apply_checks`             | `apply_checks_and_split`              | `apply_checks_and_save_in_table`             |
+| Metadata (`list[dict]`, loadable from YAML / JSON / Delta — see `dqx-storage`) | `apply_checks_by_metadata` | `apply_checks_by_metadata_and_split`  | `apply_checks_by_metadata_and_save_in_table` |
+
+For the end-to-end methods see the `dqx-end-to-end` skill. Streaming uses the same methods as batch.
+
+## Examples
+
+### Using DQX Classes
+
+```python
+from databricks.labs.dqx import check_funcs
+from databricks.labs.dqx.engine import DQEngine
+from databricks.labs.dqx.rule import DQRowRule, DQDatasetRule
+from databricks.sdk import WorkspaceClient
+# `spark` is available in Databricks notebooks / jobs. Locally, create it with
+# `from pyspark.sql import SparkSession; spark = SparkSession.builder.getOrCreate()`.
+
+dq = DQEngine(WorkspaceClient())
+
+checks = [
+    DQRowRule(criticality="warn",  check_func=check_funcs.is_not_null,   column="col3"),
+    DQDatasetRule(criticality="error", check_func=check_funcs.is_unique, columns=["col1", "col2"]),
+]
+
+df = spark.read.table("catalog.schema.input")
+
+# Option A — one output DataFrame with _warnings / _errors columns appended.
+annotated = dq.apply_checks(df, checks)
+
+# Option B — split on error severity. Warnings ride along with valid_df.
+valid_df, invalid_df = dq.apply_checks_and_split(df, checks)
+```
+
+### Using Metadata (loaded from storage)
+
+```python
+dq = DQEngine(WorkspaceClient())
+
+checks_metadata = """
+- criticality: warn
+  check:
+    function: is_not_null
+    arguments:
+      column: col3
+
+- criticality: error
+  check:
+    function: is_unique
+    arguments:
+      columns: [col1, col2]
+"""
+
+# Option A — one output DataFrame with _warnings / _errors columns appended.
+annotated = dq.apply_checks_by_metadata(df, checks_metadata)
+
+# Option B — split on error severity. Warnings ride along with valid_df.
+valid_df, invalid_df = dq.apply_checks_by_metadata_and_split(df, checks_metadata)
+```
+
+## Result shape
+
+By default two struct columns are appended:
+
+- **`_errors`** — an array of result structs, one per failing error-criticality rule.
+- **`_warnings`** — same, for warn-criticality rules.
+
+Each result struct contains: `name`, `message`, `columns`, `filter`, `function`, `run_time`, `run_id`, `user_metadata`, `rule_fingerprint`, `rule_set_fingerprint`, and (for rules that couldn't be evaluated) `skipped=true` with a reason.
+
+Column names and the skipped-entry behavior are configurable — see [Additional Configuration](https://databrickslabs.github.io/dqx/docs/guide/additional_configuration) for `ExtraParams`, `result_column_names`, and `suppress_skipped`.
+
+## Streaming
+
+Use `spark.readStream` / `writeStream` as normal; the same `apply_checks*` calls work on streaming DataFrames. For incremental batch-style execution out of the box, use `apply_checks_and_save_in_table` with the default `AvailableNow` trigger (see `dqx-end-to-end`).
+
+## Multiple inputs
+
+- `apply_checks_and_save_in_tables(run_configs)` — one call processes many `(input, output)` pairs defined by `RunConfig` entries.
+- `apply_checks_and_save_in_tables_for_patterns(patterns=["catalog.schema.*"], checks_location="catalog.schema.checks", run_config_template=RunConfig(...))` — expand wildcards against Unity Catalog. `patterns` is a `list[str]`; `checks_location` is required and is used as a template for per-table file lookups or as the shared Delta table. See [Applying Checks](https://databrickslabs.github.io/dqx/docs/guide/quality_checks_apply) for the full signature.
+
+## Do / Don't
+
+- **Do** fail fast: `DQEngine.validate_checks(checks)` raises on bad definitions before you touch data.
+- **Do** persist the split result (`invalid_df`) to a quarantine table — not just the annotated DataFrame — so downstream consumers see only good rows.
+- **Don't** mix DQX classes and metadata in one call; pick one form per invocation.
+- **Don't** drop the `_errors` / `_warnings` columns unless you've materialised the result elsewhere — they're how downstream tooling sees what failed.
+
+Canonical docs: <https://databrickslabs.github.io/dqx/docs/guide/quality_checks_apply>.