diff --git a/Makefile b/Makefile
index d9e7f1e..0100f9d 100644
--- a/Makefile
+++ b/Makefile
@@ -1,15 +1,18 @@
 VENV := .venv/bin
 
+# ruff: prefer the project venv, fall back to `uvx ruff` when no venv is present
+RUFF := $(shell [ -x .venv/bin/ruff ] && echo .venv/bin/ruff || echo "uvx ruff")
+
 .PHONY: test lint fmt typecheck check hooks
 
 test:
 	$(VENV)/pytest tests/ -v
 
 lint:
-	$(VENV)/ruff check src/ tests/
+	$(RUFF) check src/ tests/
 
 fmt:
-	$(VENV)/ruff format src/ tests/
+	$(RUFF) format src/ tests/
 
 typecheck:
 	$(VENV)/pyright src/
diff --git a/src/codeatrium/cli/prime_cmd.py b/src/codeatrium/cli/prime_cmd.py
index 52837c6..139d5b3 100644
--- a/src/codeatrium/cli/prime_cmd.py
+++ b/src/codeatrium/cli/prime_cmd.py
@@ -41,6 +41,37 @@
 
 # Retrieve past conversations from work on a specific branch
 loci context --branch "feature/foo" --json
+```
+
+### IDE selection as a deictic anchor
+
+When the IDE injects an active editor selection (shown as `⧉ Selected N lines from <file>`), treat that selection as the referent of "this / これ / この〜" in the user's prompt. The selection resolves *which* symbol the memory lookup is about — it is NOT by itself a request to recall.
+
+Recall from a selection ONLY when BOTH hold:
+
+1. a selection is active, AND
+2. either (a) the user asks about the past — recall / why / history / decisions ("この実装の時の会話を思い出して", "これ前にどう決めた?"), or (b) your own next action on the selected code (edit / refactor / debug) needs prior decisions or constraints.
+
+Do NOT recall when the selection is present only because the user is about to edit it and asks nothing past-oriented.
+
+Map the selection to a query:
+
+- Selection IS a named function/class → look it up directly:
+
+```bash
+loci context --symbol "<name>" --json
+```
+
+- Selection is a fragment INSIDE one function/class — the `def`/`class` line is usually not in the selection, so resolve the enclosing symbol first (LSP `workspaceSymbol`/`hover`, or read `<file>` around the selection), then:
+
+```bash
+loci context --symbol "<enclosing-symbol>" --json
+```
+
+- Selection spans multiple symbols or belongs to none (module-level code, config, comments), OR the lookups above return no results → fall back to semantic search over your question:
+
+```bash
+loci search "<the user's question>" --json
 ```\
 """
 
diff --git a/tests/test_prime_cmd.py b/tests/test_prime_cmd.py
index 3722bb9..b8456f2 100644
--- a/tests/test_prime_cmd.py
+++ b/tests/test_prime_cmd.py
@@ -44,6 +44,40 @@ def test_prime_text_context_section_explains_bidirectional_recall():
     )
 
 
+# ---- IDE selection trigger contract ----
+
+
+def test_prime_text_has_ide_selection_section():
+    """PRIME_TEXT must explain IDE selection as a deictic anchor for context recall"""
+    assert "IDE selection as a deictic anchor" in PRIME_TEXT
+
+
+def test_prime_text_ide_selection_requires_conjunction():
+    """A selection alone must NOT trigger recall — requires selection AND a recall need"""
+    text_lower = PRIME_TEXT.lower()
+    assert "only when both" in text_lower
+    # both branches of the recall need must be present
+    assert "asks about the past" in text_lower
+    assert "your own next action" in text_lower
+
+
+def test_prime_text_ide_selection_guards_against_over_fire():
+    """PRIME_TEXT must tell the agent NOT to recall on edit-only selections"""
+    assert "Do NOT recall" in PRIME_TEXT
+
+
+def test_prime_text_ide_selection_resolves_enclosing_symbol_for_fragments():
+    """A fragment selection must resolve its enclosing symbol before context lookup"""
+    assert "enclosing symbol" in PRIME_TEXT
+
+
+def test_prime_text_ide_selection_has_search_fallback():
+    """When no single symbol applies or context is empty, fall back to loci search"""
+    text_lower = PRIME_TEXT.lower()
+    assert "spans multiple symbols" in text_lower
+    assert "return no results" in text_lower
+
+
 # ---- inject_claude_md idempotency ----