feat(writes): enable write actions by default (opt-out)

Invert the global write toggle so writes are ENABLED by default and the
user opts OUT, while keeping all other safety intact (per-call confirm=true
dry-run preview and the on-disk audit log are unchanged).

- writes.py: use a `writes_disabled` flag file instead of `writes_enabled`;
  `writes_enabled()` returns True unless the flag exists (env var still
  honored either way); `set_writes(False)` creates the flag, `set_writes(True)`
  removes it. Update user-facing notes.
- tests: default is now ENABLED; adjust toggle/disabled tests (set disabled
  explicitly via set_writes(False) or FAMILIAR_ENABLE_WRITES=0).
- README.md / CLAUDE.md: document writes are on by default, opt out via
  `familiar writes disable`.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

CLAUDE.md

@@ -19,7 +19,7 @@ uv run ruff check .           # lint (run both before committing; CI enforces th
 uv run familiar               # run the MCP server over stdio (how Claude launches it)
 uv run familiar login         # browser EVE SSO login (adds a character; run once per character)
 uv run familiar status        # list logged-in characters
-uv run familiar writes enable # allow write actions (default: disabled)
+uv run familiar writes disable # block write actions (default: enabled)
 ```
 
 There is no separate build step; `uv build` produces the wheel (CI does this on merge).
@@ -34,7 +34,7 @@ There is no separate build step; `uv build` produces the wheel (CI does this on
 
 **Per-character / per-corp pattern.** [charutil.py](src/familiar/charutil.py) is the backbone of every authenticated tool. `run_per_character(character, fetch)` runs a fetcher for one named character or **all** logged-in ones (when `character` is None), returning a uniform `{"characters": [...]}`. `run_per_corp` additionally resolves each character's `corporation_id` (corp endpoints need the right corp role or ESI 403s). `one_token` picks a single token for thing-scoped lookups (e.g. a structure). `summarize(items, limit)` gives `{count, sample}`. account.py and all read modules build on these.
 
-**Write safety — the choke point.** [writes.py](src/familiar/writes.py) `guard(action, params, confirm, execute)` is the single gate every mutating tool calls. `confirm=False` → dry-run preview (nothing happens); `confirm=True` but writes disabled → `WriteDisabled`; `confirm=True` + enabled → execute + append to an audit log. Writes are **off by default** (toggle via `familiar writes enable` / `FAMILIAR_ENABLE_WRITES`). Write tools take a *required* `character` and a `confirm` flag; reads take an *optional* `character`. When adding a write tool, route it through `writes.guard` — never call a mutating ESI endpoint directly.
+**Write safety — the choke point.** [writes.py](src/familiar/writes.py) `guard(action, params, confirm, execute)` is the single gate every mutating tool calls. `confirm=False` → dry-run preview (nothing happens); `confirm=True` but writes disabled → `WriteDisabled`; `confirm=True` + enabled → execute + append to an audit log. Writes are **on by default** (opt out via `familiar writes disable`; toggle via `familiar writes enable`/`disable` or `FAMILIAR_ENABLE_WRITES`). Write tools take a *required* `character` and a `confirm` flag; reads take an *optional* `character`. When adding a write tool, route it through `writes.guard` — never call a mutating ESI endpoint directly.
 
 ## Testing conventions
 

README.md

@@ -8,7 +8,7 @@ Ask your familiar where your assets are, what your skill queue looks like, what
 
 ## Principles
 
-- **Safe by default.** Reading is free; every *write* — sending mail, setting waypoints, editing contacts/fittings/PI, fleet commands — is off until you turn it on, previewed before it runs, and recorded in an audit log. The AI can see everything and changes nothing unless you let it.
+- **Safe by default.** Reading is free; every *write* — sending mail, setting waypoints, editing contacts/fittings/PI, fleet commands — is previewed before it runs (nothing happens without `confirm=true`) and recorded in an audit log. Writes are on by default but can be turned off entirely with `familiar writes disable`. The AI can see everything and changes nothing without your explicit confirm.
 - **Local-first.** Runs on your own machine. Your refresh token and account data never leave your control.
 - **Everything, eventually.** The goal is full coverage: the ESI scopes you grant (character *and* corp, read and write), plus the complete static universe. Built in phases so it actually ships.
 
@@ -49,12 +49,14 @@ Claude Desktop (`claude_desktop_config.json`):
 
 Then ask in natural language — "what's Tritanium worth in Jita?", "how much ISK across all my characters?", "where are my characters?".
 
-### Enabling writes
+### Write actions
 
-Write actions (send mail, set waypoints, edit contacts/fittings, fleet commands) are **off by default**. Every write tool also returns a dry-run preview unless called with `confirm=true`, and each executed write is recorded in an audit log.
+Write actions (send mail, set waypoints, edit contacts/fittings, fleet commands) are **on by default**. Even so, every write tool returns a dry-run preview unless called with `confirm=true` per call, and each executed write is recorded in an audit log — so nothing changes by accident.
+
+To opt out and block all writes globally:
 
 ```bash
-uv run familiar writes enable   # allow writes (uv run familiar writes disable to revoke)
+uv run familiar writes disable   # turn writes off (uv run familiar writes enable to re-allow)
 ```
 
 ## Roadmap

src/familiar/writes.py

@@ -3,7 +3,7 @@
 familiar is safe by default: a write only happens when **all** of these hold:
 
 1. the caller passes ``confirm=True`` (otherwise it gets a dry-run preview), and
-2. writes are enabled globally (`familiar writes enable`, default off).
+2. writes are enabled globally (on by default; opt out via `familiar writes disable`).
 
 Every executed write is appended to an audit log on disk. This module is the
 single choke point every write tool must go through.
@@ -25,24 +25,29 @@ class WriteDisabled(RuntimeError):
 
 
 def _flag_file():
-    return config.data_dir() / "writes_enabled"
+    return config.data_dir() / "writes_disabled"
 
 
 def writes_enabled() -> bool:
-    """True if writes are allowed (env override or the on-disk toggle)."""
+    """True if writes are allowed (env override or the on-disk toggle).
+
+    Writes are **enabled by default**; the user opts out by creating the
+    disable-flag file (`familiar writes disable`) or setting the env var.
+    """
     env = os.environ.get("FAMILIAR_ENABLE_WRITES")
     if env is not None:
         return env.strip().lower() in {"1", "true", "yes", "on"}
-    return _flag_file().exists()
+    return not _flag_file().exists()
 
 
 def set_writes(enabled: bool) -> None:
-    """Turn the on-disk write toggle on or off."""
+    """Turn the on-disk write toggle on or off (writes are on by default)."""
     flag = _flag_file()
     if enabled:
-        flag.write_text("enabled\n", encoding="utf-8")
-    elif flag.exists():
-        flag.unlink()
+        if flag.exists():
+            flag.unlink()
+    else:
+        flag.write_text("disabled\n", encoding="utf-8")
 
 
 def audit_log_path():
@@ -77,7 +82,7 @@ async def guard(
     if not writes_enabled():
         raise WriteDisabled(
             f"Writes are disabled, so '{action}' was not performed. "
-            "Run `familiar writes enable` to allow write actions."
+            "Run `familiar writes enable` to re-allow write actions."
         )
     result = await execute()
     _audit({"action": action, "params": params})
@@ -92,5 +97,5 @@ def register(mcp) -> None:
         """Whether familiar is currently allowed to perform write actions."""
         return {
             "writes_enabled": writes_enabled(),
-            "note": "Enable with `familiar writes enable`; write tools also need confirm=true.",
+            "note": "On by default; disable with `familiar writes disable`. Write tools also need confirm=true.",
         }

tests/test_comms.py

@@ -46,7 +46,7 @@ def test_send_mail_dry_run_does_not_post(mock_esi, fake_auth):
 
 def test_send_mail_disabled_raises(mock_esi, fake_auth, tmp_path, monkeypatch):
     monkeypatch.setenv("FAMILIAR_DATA_DIR", str(tmp_path))
-    monkeypatch.delenv("FAMILIAR_ENABLE_WRITES", raising=False)
+    monkeypatch.setenv("FAMILIAR_ENABLE_WRITES", "0")
     mock_esi(lambda r: httpx.Response(201, json=1))
     with pytest.raises(writes.WriteDisabled):
         asyncio.run(comms.send_mail(99, [{"recipient_id": 1}], "s", "b", confirm=True))

tests/test_contacts_fittings.py

@@ -70,7 +70,7 @@ def test_get_fittings(mock_esi, fake_auth):
 
 def test_create_fitting_disabled_raises(mock_esi, fake_auth, tmp_path, monkeypatch):
     monkeypatch.setenv("FAMILIAR_DATA_DIR", str(tmp_path))
-    monkeypatch.delenv("FAMILIAR_ENABLE_WRITES", raising=False)
+    monkeypatch.setenv("FAMILIAR_ENABLE_WRITES", "0")
     mock_esi(lambda r: httpx.Response(201, json={"fitting_id": 5}))
     with pytest.raises(writes.WriteDisabled):
         asyncio.run(fittings.create_fitting(99, {"name": "x"}, confirm=True))

tests/test_writes.py

@@ -19,15 +19,15 @@ async def _exec():
     return {"ok": True}
 
 
-def test_disabled_by_default(tmp_data):
-    assert writes.writes_enabled() is False
+def test_enabled_by_default(tmp_data):
+    assert writes.writes_enabled() is True
 
 
 def test_toggle_on_disk(tmp_data):
-    writes.set_writes(True)
-    assert writes.writes_enabled() is True
     writes.set_writes(False)
     assert writes.writes_enabled() is False
+    writes.set_writes(True)
+    assert writes.writes_enabled() is True
 
 
 def test_env_override(tmp_data, monkeypatch):
@@ -50,12 +50,18 @@ def test_dry_run_does_not_execute(tmp_data):
 
 
 def test_confirm_but_disabled_raises(tmp_data):
+    writes.set_writes(False)
+    with pytest.raises(writes.WriteDisabled):
+        asyncio.run(writes.guard("send_mail", {}, confirm=True, execute=_exec))
+
+
+def test_confirm_but_disabled_via_env_raises(tmp_data, monkeypatch):
+    monkeypatch.setenv("FAMILIAR_ENABLE_WRITES", "0")
     with pytest.raises(writes.WriteDisabled):
         asyncio.run(writes.guard("send_mail", {}, confirm=True, execute=_exec))
 
 
 def test_confirm_enabled_executes_and_audits(tmp_data):
-    writes.set_writes(True)
     result = asyncio.run(writes.guard("send_mail", {"subject": "hi"}, confirm=True, execute=_exec))
     assert result["executed"] is True
     assert result["result"] == {"ok": True}