diff --git a/app/schemas.py b/app/schemas/__init__.py
similarity index 100%
rename from app/schemas.py
rename to app/schemas/__init__.py
diff --git a/app/schemas/contextual.py b/app/schemas/contextual.py
new file mode 100644
index 0000000..b995168
--- /dev/null
+++ b/app/schemas/contextual.py
@@ -0,0 +1,73 @@
+"""Contextual sidebar scope schema and prompt block renderer.
+
+ContextualScope mirrors the TypeScript ContextualScope type sent by the
+Electron renderer when the user opens the side chat anchored to a specific
+view.  The renderer ships camelCase keys; Pydantic's alias_generator maps
+them to snake_case Python attributes automatically.
+"""
+
+from __future__ import annotations
+
+from typing import Literal, Optional
+
+from pydantic import BaseModel, ConfigDict
+from pydantic.alias_generators import to_camel
+
+
+PageType = Literal[
+    "timeline",
+    "tasks",
+    "projects-list",
+    "project",
+    "note",
+]
+
+EntityType = Literal["project", "note", "task", "timeline_event"]
+
+
+class ContextualScope(BaseModel):
+    """Scope payload sent by the Electron renderer for contextual chat.
+
+    The renderer ships camelCase keys (entityType, entityId, ...).  Pydantic's
+    alias generator maps them to snake_case Python attrs.
+    """
+
+    model_config = ConfigDict(populate_by_name=True, alias_generator=to_camel)
+
+    page: PageType
+    entity_type: Optional[EntityType] = None
+    entity_id: Optional[str] = None
+    entity_name: Optional[str] = None
+    project_id: Optional[str] = None
+    char_count: Optional[int] = None
+    counts: Optional[dict[str, int]] = None
+    filters: Optional[dict] = None
+
+
+def render_scope_block(scope: ContextualScope) -> str:
+    """Produce a single-paragraph human-readable summary of the current view
+    for injection into the contextual agent system prompt.
+
+    Never emits internal ids — only names.  The LLM is told to use names in
+    prose; ids travel through tool calls.
+    """
+    if scope.entity_type == "project":
+        c = scope.counts or {}
+        return (
+            f"User is viewing the project {scope.entity_name!r}. "
+            f"{c.get('tasks', 0)} tasks, "
+            f"{c.get('notes', 0)} notes, "
+            f"{c.get('milestones', 0)} milestones."
+        )
+    if scope.entity_type == "note":
+        return (
+            f"User is viewing the note {scope.entity_name!r} "
+            f"({scope.char_count or 0} characters)."
+        )
+    if scope.page == "tasks":
+        return "User is viewing the global Tasks list (all projects)."
+    if scope.page == "timeline":
+        return "User is viewing the global Timeline view."
+    if scope.page == "projects-list":
+        return "User is viewing the Projects list."
+    return f"User is on page {scope.page}."
diff --git a/tests/test_contextual_scope.py b/tests/test_contextual_scope.py
new file mode 100644
index 0000000..ba25b31
--- /dev/null
+++ b/tests/test_contextual_scope.py
@@ -0,0 +1,52 @@
+import pytest
+from app.schemas.contextual import ContextualScope, render_scope_block
+
+
+def test_render_project_scope():
+    scope = ContextualScope(
+        page="project",
+        entity_type="project",
+        entity_id="p1",
+        entity_name="Acme Q3 launch",
+        counts={"tasks": 12, "notes": 4, "milestones": 3},
+    )
+    block = render_scope_block(scope)
+    assert "Acme Q3 launch" in block
+    assert "12 tasks" in block
+    assert "4 notes" in block
+    assert "3 milestones" in block
+    assert "p1" not in block
+
+
+def test_render_list_scope_no_entity():
+    scope = ContextualScope(page="tasks", entity_type=None)
+    block = render_scope_block(scope)
+    assert "tasks" in block.lower()
+    assert "None" not in block
+
+
+def test_render_note_scope_includes_char_count():
+    scope = ContextualScope(
+        page="note",
+        entity_type="note",
+        entity_id="n1",
+        entity_name="Meeting 14 May",
+        project_id="p1",
+        char_count=4280,
+    )
+    block = render_scope_block(scope)
+    assert "Meeting 14 May" in block
+    assert "4280" in block or "4,280" in block
+
+
+def test_parses_camelcase_payload_from_renderer():
+    payload = {
+        "page": "project",
+        "entityType": "project",
+        "entityId": "p1",
+        "entityName": "Acme",
+        "counts": {"tasks": 5, "notes": 1, "milestones": 2},
+    }
+    scope = ContextualScope.model_validate(payload)
+    assert scope.entity_id == "p1"
+    assert scope.entity_name == "Acme"