feat: add reminders_remove tool for single-reminder removal

- reminders_remove(index) removes one reminder by 1-based index
- reminders_list now returns numbered output (1. heading / body)
  so any model can easily identify which index to pass
- _parse_sections() / _sections_to_text() helpers for clean round-trip
- Not in CONFIRM_REQUIRED — targeted removal is safe without a gate

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

cortex/tools/__init__.py

@@ -37,6 +37,7 @@ from tools.cron import (
 from tools.reminders import (
     reminders_add as _reminders_add,
     reminders_list as _reminders_list,
+    reminders_remove as _reminders_remove,
     reminders_clear as _reminders_clear,
 )
 from tools.scratch import (
@@ -308,6 +309,7 @@ _CALLABLES: dict[str, callable] = {
     "cron_toggle": _cron_toggle,
     "reminders_add": _reminders_add,
     "reminders_list": _reminders_list,
+    "reminders_remove": _reminders_remove,
     "reminders_clear": _reminders_clear,
     "scratch_read": _scratch_read,
     "scratch_write": _scratch_write,
@@ -584,6 +586,24 @@ _reminders_list_declaration = types.FunctionDeclaration(
     parameters=types.Schema(type=types.Type.OBJECT, properties={}),
 )
 
+_reminders_remove_declaration = types.FunctionDeclaration(
+    name="reminders_remove",
+    description=(
+        "Remove a single reminder by its number. "
+        "Call reminders_list first to get the numbered list, then pass the number of the reminder to remove."
+    ),
+    parameters=types.Schema(
+        type=types.Type.OBJECT,
+        properties={
+            "index": types.Schema(
+                type=types.Type.INTEGER,
+                description="The number of the reminder to remove (1 = first item in reminders_list output).",
+            ),
+        },
+        required=["index"],
+    ),
+)
+
 _reminders_clear_declaration = types.FunctionDeclaration(
     name="reminders_clear",
     description=(
@@ -864,6 +884,7 @@ _ALL_DECLARATIONS: list[types.FunctionDeclaration] = [
     _cron_toggle_declaration,
     _reminders_add_declaration,
     _reminders_list_declaration,
+    _reminders_remove_declaration,
     _reminders_clear_declaration,
     _scratch_read_declaration,
     _scratch_write_declaration,

cortex/tools/reminders.py

@@ -27,6 +27,28 @@ def _now_label() -> str:
     return datetime.now(timezone.utc).strftime("%Y-%m-%d %H:%M UTC")
 
 
+def _parse_sections(text: str) -> list[tuple[str, str]]:
+    """Split REMINDERS.md into (heading, body) tuples, one per ## section."""
+    sections: list[tuple[str, str]] = []
+    heading: str | None = None
+    body_lines: list[str] = []
+    for line in text.splitlines():
+        if line.startswith("## "):
+            if heading is not None:
+                sections.append((heading, "\n".join(body_lines).strip()))
+            heading = line[3:].strip()
+            body_lines = []
+        elif heading is not None:
+            body_lines.append(line)
+    if heading is not None:
+        sections.append((heading, "\n".join(body_lines).strip()))
+    return sections
+
+
+def _sections_to_text(sections: list[tuple[str, str]]) -> str:
+    return "".join(f"\n## {h}\n\n{b}\n" for h, b in sections)
+
+
 # ---------------------------------------------------------------------------
 # Sync implementations
 # ---------------------------------------------------------------------------
@@ -35,7 +57,18 @@ def _reminders_list() -> str:
     p = _reminders_path()
     if not p.exists() or not p.read_text().strip():
         return "No pending reminders."
-    return p.read_text()
+    sections = _parse_sections(p.read_text())
+    if not sections:
+        return "No pending reminders."
+    lines = []
+    for i, (heading, body) in enumerate(sections, 1):
+        lines.append(f"{i}. {heading}")
+        if body:
+            # Indent body so it reads as belonging to the numbered item
+            for bline in body.splitlines()[:4]:  # cap at 4 lines for brevity
+                lines.append(f"   {bline}")
+        lines.append("")
+    return "\n".join(lines).rstrip()
 
 
 def _reminders_add(text: str, label: str | None = None) -> str:
@@ -47,6 +80,26 @@ def _reminders_add(text: str, label: str | None = None) -> str:
     return f"Reminder added: {heading}"
 
 
+def _reminders_remove(index: int) -> str:
+    p = _reminders_path()
+    if not p.exists() or not p.read_text().strip():
+        return "No reminders to remove."
+    sections = _parse_sections(p.read_text())
+    if not sections:
+        return "No reminders to remove."
+    if index < 1 or index > len(sections):
+        return (
+            f"Index {index} is out of range. "
+            f"There {'is' if len(sections) == 1 else 'are'} {len(sections)} "
+            f"reminder{'s' if len(sections) != 1 else ''} (1–{len(sections)}). "
+            "Call reminders_list to see them."
+        )
+    removed_heading = sections[index - 1][0]
+    sections.pop(index - 1)
+    p.write_text(_sections_to_text(sections))
+    return f"Removed reminder {index}: {removed_heading}"
+
+
 def _reminders_clear() -> str:
     p = _reminders_path()
     p.write_text("")
@@ -65,5 +118,9 @@ async def reminders_add(text: str, label: str | None = None) -> str:
     return await asyncio.to_thread(_reminders_add, text, label)
 
 
+async def reminders_remove(index: int) -> str:
+    return await asyncio.to_thread(_reminders_remove, index)
+
+
 async def reminders_clear() -> str:
     return await asyncio.to_thread(_reminders_clear)