feat(wren): generate AGENTS.md during wren context init

wren/src/wren/context.py

@@ -17,6 +17,68 @@
 _TARGET_DIR = "target"
 _TARGET_FILE = "mdl.json"
 
+_AGENTS_MD_TEMPLATE = """\
+# AGENTS.md
+
+This project uses [Wren Engine](https://github.com/Canner/wren-engine) as the semantic layer for data querying. Queries are written against MDL model names, not raw database tables.
+
+## Answering data questions
+
+When the user asks about data, metrics, reports, or business questions, follow this workflow:
+
+1. `wren memory fetch -q "<question>"` — get relevant schema context
+2. `wren memory recall -q "<question>" --limit 3` — find similar past queries
+3. Write SQL using model names from the MDL (not raw table names)
+4. `wren --sql "<sql>"` — execute through the semantic layer
+5. `wren memory store --nl "<question>" --sql "<sql>"` — store confirmed results
+
+If this is the first query in the session, also run `wren context instructions` to load business rules.
+
+## Modifying the data model
+
+When the user wants to add models, change schema, or onboard a new table:
+
+1. Edit YAML files in `models/`, `views/`, or `relationships.yml`
+2. `wren context validate` — check structure
+3. `wren context build` — compile to `target/mdl.json`
+4. `wren memory index` — re-index schema for search
+
+## Prerequisites
+
+This project requires the `wren` CLI. If not installed:
+
+```bash
+pip install "wren-engine[memory]"
+```
+
+Each data source needs its own extra — install the one matching your `data_source` in `wren_project.yml`:
+
+```bash
+pip install "wren-engine[postgres]"   # or mysql, bigquery, snowflake, clickhouse,
+                                      # trino, mssql, databricks, redshift, spark,
+                                      # athena, oracle
+```
+
+Or install everything at once:
+
+```bash
+pip install "wren-engine[all]"
+```
+
+See https://docs.getwren.ai/oss/engine/get_started/installation for full setup.
+
+## Quick reference
+
+| Task | Command |
+|------|---------|
+| Run a query | `wren --sql "SELECT ..."` |
+| Preview planned SQL | `wren dry-plan --sql "SELECT ..."` |
+| Show available models | `wren context show` |
+| Check connection | `wren profile debug` |
+| Check memory index | `wren memory status` |
+| Rebuild after changes | `wren context build && wren memory index` |
+"""
+
 
 # ── Case conversion ───────────────────────────────────────────────────────
 
@@ -195,6 +257,14 @@ def convert_mdl_to_project(mdl_json: dict) -> list[ProjectFile]:
             )
         )
 
+    # ── AGENTS.md ──────────────────────────────────────────────
+    files.append(
+        ProjectFile(
+            relative_path="AGENTS.md",
+            content=_AGENTS_MD_TEMPLATE,
+        )
+    )
+
     return files
 
 
@@ -223,6 +293,7 @@ def write_project_files(
             "relationships.yml",
             "instructions.md",
             "wren_project.yml",
+            "AGENTS.md",
         ):
             target = output_dir / managed
             if target.is_dir():

wren/src/wren/context_cli.py

@@ -79,9 +79,12 @@ def init(
 
     # ── Scaffold empty project (existing behavior) ────────────
     project_file = project_path / "wren_project.yml"
-    if project_file.exists() and not force:
+    agents_file = project_path / "AGENTS.md"
+    conflicts = [f for f in (project_file, agents_file) if f.exists()]
+    if conflicts and not force:
+        names = ", ".join(f"'{c.name}'" for c in conflicts)
         typer.echo(
-            f"Error: '{project_file}' already exists. This is already a Wren project.",
+            f"Error: {names} already exists. This is already a Wren project.",
             err=True,
         )
         raise typer.Exit(1)
@@ -167,12 +170,18 @@ def init(
         "Add custom rules or guidelines for LLM-based query generation here.\n"
     )
 
+    # ── AGENTS.md ──
+    from wren.context import _AGENTS_MD_TEMPLATE  # noqa: PLC0415
+
+    (project_path / "AGENTS.md").write_text(_AGENTS_MD_TEMPLATE)
+
     typer.echo(f"Wren project initialized: {project_path}")
     typer.echo("  wren_project.yml            — project metadata (edit data_source)")
     typer.echo("  models/example/             — example model (metadata.yml)")
     typer.echo("  views/example_view/         — example view (metadata.yml + sql.yml)")
     typer.echo("  relationships.yml           — define joins between models")
     typer.echo("  instructions.md             — LLM instructions")
+    typer.echo("  AGENTS.md                   — AI agent workflow guidance")
     typer.echo("\nNext: edit your models, then run `wren context build`.")