diff --git a/README.md b/README.md
index e0c14d7..8338359 100644
--- a/README.md
+++ b/README.md
@@ -337,7 +337,7 @@ scripts:
 ```
 workforest create [BRANCH] [-o OPENER] [-w WRAPPER] [-p PATH] [--no-hooks] [--no-open]
 workforest open   [NAME]   [-o OPENER] [-w WRAPPER] [-p PATH]
-workforest list   [--porcelain]
+workforest list   [--porcelain | --json]
 workforest delete NAME...  [--force] [--delete-branch | --keep-branch]
 workforest checkout NAME   [--force]
 workforest run    [-b] SCRIPT [ARGS...]
@@ -365,7 +365,11 @@ which is not a stable interface, so any Claude Code update may break it.
 Exit codes: `0` ok · `1` error · `2` usage · `3` cancelled · `4` config error
 · `128+N` the `run` command was killed by signal N.
 Human messages go to stderr; stdout carries only machine output (`cd`
-directives for the `wf` wrapper, `--porcelain` listings, dumps).
+directives for the `wf` wrapper, `--porcelain`/`--json` listings, dumps).
+`list --json` describes the whole forest for programs — `main` (the main
+checkout, in the same `name`/`branch`/`path`/`dirty` shape as each entry of
+`worktrees`) and the resolved `worktrees_dir` — for editor integrations
+and other programs.
 
 ## Development
 
diff --git a/man/workforest.1 b/man/workforest.1
index 15d2626..6048611 100644
--- a/man/workforest.1
+++ b/man/workforest.1
@@ -31,7 +31,7 @@ workforest, wf \- git worktree forest management
 .IR PATH ]
 .YS
 .SY "workforest list"
-.RB [ \-\-porcelain ]
+.RB [ \-\-porcelain " | " \-\-json ]
 .YS
 .SY "workforest delete"
 .IR NAME .\|.\|.
@@ -188,6 +188,23 @@ and
 (dirty) or
 .B 0
 (clean), separated by tabs.
+.TP
+.B \-\-json
+The whole forest as a JSON object, for editor integrations and other
+programs:
+.B main
+(the main checkout) and each entry of
+.B worktrees
+carry
+.BR name ,
+.B branch
+(null when detached),
+.BR path ,
+and
+.B dirty
+(true/false);
+.B worktrees_dir
+is the resolved worktrees directory.
 .SS delete \fINAME\fR...
 Delete one or more worktrees.
 Every name is resolved before anything is removed, so a typo fails the
diff --git a/src/workforest/cli.py b/src/workforest/cli.py
index 53ff258..e508a21 100644
--- a/src/workforest/cli.py
+++ b/src/workforest/cli.py
@@ -83,7 +83,7 @@ def _handle_open(ns: argparse.Namespace) -> CommandResult:
 
 def _handle_list(ns: argparse.Namespace) -> CommandResult:
     ctx = commands.build_context()
-    return commands.cmd_list(ctx, porcelain=ns.porcelain)
+    return commands.cmd_list(ctx, porcelain=ns.porcelain, as_json=ns.json)
 
 
 def _handle_delete(ns: argparse.Namespace) -> CommandResult:
@@ -177,7 +177,11 @@ def opener_args(p: argparse.ArgumentParser) -> None:
     p.set_defaults(func=_handle_open)
 
     p = sub.add_parser("list", help=SUBCOMMAND_HELP["list"])
-    p.add_argument("--porcelain", action="store_true", help="stable tab-separated output")
+    group = p.add_mutually_exclusive_group()
+    group.add_argument("--porcelain", action="store_true", help="stable tab-separated output")
+    group.add_argument(
+        "--json", action="store_true", help="the whole forest (main checkout included) as JSON"
+    )
     p.set_defaults(func=_handle_list)
 
     p = sub.add_parser("delete", help=SUBCOMMAND_HELP["delete"])
diff --git a/src/workforest/commands.py b/src/workforest/commands.py
index b16a7f0..435e8bd 100644
--- a/src/workforest/commands.py
+++ b/src/workforest/commands.py
@@ -6,6 +6,7 @@
 from concurrent.futures import ThreadPoolExecutor
 from dataclasses import dataclass
 from pathlib import Path
+from typing import Any
 
 import yaml
 
@@ -42,14 +43,14 @@ def build_context(cwd: Path | None = None) -> Context:
     return Context(cwd_root=cwd_root, main=main, config=config, worktrees_dir=worktrees_dir)
 
 
+def _is_managed(ctx: Context, worktree: gitutil.Worktree) -> bool:
+    return not worktree.is_main and worktree.path.parent == ctx.worktrees_dir
+
+
 def managed_worktrees(ctx: Context) -> list[gitutil.Worktree]:
     """Worktrees located directly inside the resolved worktrees dir —
     the only ones we list, complete, or delete."""
-    return [
-        worktree
-        for worktree in gitutil.list_worktrees(ctx.main)
-        if not worktree.is_main and worktree.path.parent == ctx.worktrees_dir
-    ]
+    return [w for w in gitutil.list_worktrees(ctx.main) if _is_managed(ctx, w)]
 
 
 def find_managed(ctx: Context, name: str) -> gitutil.Worktree:
@@ -198,16 +199,47 @@ def cmd_open(
     )
 
 
-def cmd_list(ctx: Context, *, porcelain: bool = False) -> CommandResult:
+def _dirty_flags(worktrees: list[gitutil.Worktree]) -> list[bool]:
+    """One `git status` per worktree; subprocess-bound, so run them together."""
+    if not worktrees:
+        return []
+    with ThreadPoolExecutor(max_workers=min(8, len(worktrees))) as pool:
+        return list(pool.map(lambda w: bool(gitutil.status_porcelain(w.path)), worktrees))
+
+
+def _worktree_json(worktree: gitutil.Worktree, dirty: bool) -> dict[str, Any]:
+    return {
+        "name": worktree.name,
+        "branch": worktree.branch,  # null when detached
+        "path": str(worktree.path),
+        "dirty": dirty,
+    }
+
+
+def _list_json(ctx: Context) -> str:
+    """The whole forest for programs (editor integrations): the main
+    checkout in the same shape as the worktrees, plus where they live."""
+    everything = gitutil.list_worktrees(ctx.main)
+    main, worktrees = everything[0], [w for w in everything if _is_managed(ctx, w)]
+    dirty = _dirty_flags([main, *worktrees])
+    data = {
+        "main": _worktree_json(main, dirty[0]),
+        "worktrees_dir": str(ctx.worktrees_dir),
+        "worktrees": [_worktree_json(w, d) for w, d in zip(worktrees, dirty[1:], strict=True)],
+    }
+    return json.dumps(data, indent=2)
+
+
+def cmd_list(ctx: Context, *, porcelain: bool = False, as_json: bool = False) -> CommandResult:
+    if as_json:
+        return _list_json(ctx)
     worktrees = managed_worktrees(ctx)
     if not worktrees:
         if porcelain:
             return ""
         output.info(f"no worktrees in {ctx.worktrees_dir} (create one with: wf create BRANCH)")
         return None
-    # One `git status` per worktree; subprocess-bound, so run them together.
-    with ThreadPoolExecutor(max_workers=min(8, len(worktrees))) as pool:
-        dirty = list(pool.map(lambda w: bool(gitutil.status_porcelain(w.path)), worktrees))
+    dirty = _dirty_flags(worktrees)
     if porcelain:
         return "\n".join(
             "\t".join((w.name, w.branch or "", str(w.path), "1" if is_dirty else "0"))
diff --git a/tests/test_cli.py b/tests/test_cli.py
index 8396f1f..28cf239 100644
--- a/tests/test_cli.py
+++ b/tests/test_cli.py
@@ -63,6 +63,16 @@ def test_list_porcelain_on_stdout(self, run_cli: Run, repo: Repo) -> None:
         assert (name, branch, dirty) == ("feat", "feat", "0")
         assert path.endswith("worktrees/api/feat")
 
+    def test_list_json_on_stdout(self, run_cli: Run, repo: Repo) -> None:
+        import json
+
+        result = run_cli("list", "--json", cwd=repo.path)
+        assert result.code == 0
+        assert json.loads(result.out)["main"]["path"] == str(repo.path)
+
+    def test_list_formats_are_exclusive(self, run_cli: Run, repo: Repo) -> None:
+        assert run_cli("list", "--json", "--porcelain", cwd=repo.path).code == 2
+
     def test_checkout_emits_cd_to_main(self, run_cli: Run, repo: Repo) -> None:
         run_cli("create", "feat", "--no-open", cwd=repo.path)
         result = run_cli("checkout", "feat", cwd=repo.path)
diff --git a/tests/test_commands.py b/tests/test_commands.py
index 138442e..06e69d8 100644
--- a/tests/test_commands.py
+++ b/tests/test_commands.py
@@ -245,6 +245,38 @@ def test_empty_forest(self, repo: Repo) -> None:
         assert commands.cmd_list(ctx_for(repo)) is None
         assert commands.cmd_list(ctx_for(repo), porcelain=True) == ""
 
+    def test_json_covers_the_whole_forest(self, repo: Repo) -> None:
+        import json
+
+        ctx = ctx_for(repo)
+        commands.cmd_create(ctx, "feature/one", no_open=True)
+        repo.make_dirty()  # the main checkout
+        out = commands.cmd_list(ctx, as_json=True)
+        assert isinstance(out, str)
+        data = json.loads(out)
+        assert data["main"] == {
+            "name": "api",
+            "branch": "main",
+            "path": str(repo.path),
+            "dirty": True,
+        }
+        assert data["worktrees_dir"] == str(ctx.worktrees_dir)
+        assert data["worktrees"] == [
+            {
+                "name": "one",
+                "branch": "feature/one",
+                "path": str(ctx.worktrees_dir / "one"),
+                "dirty": False,
+            }
+        ]
+
+    def test_json_of_empty_forest_still_describes_main(self, repo: Repo) -> None:
+        import json
+
+        data = json.loads(commands.cmd_list(ctx_for(repo), as_json=True) or "")
+        assert data["worktrees"] == []
+        assert data["main"]["path"] == str(repo.path)
+
 
 class TestDelete:
     def test_clean_delete_keeps_branch_off_tty(self, repo: Repo) -> None: