diff --git a/benchmark/CLAUDE.threefile.md b/benchmark/CLAUDE.threefile.md
new file mode 100644
index 0000000..5d010ff
--- /dev/null
+++ b/benchmark/CLAUDE.threefile.md
@@ -0,0 +1,25 @@
+# Django Source — supermodel three-file shards enabled
+
+This is the Django framework source. The auth package is at `django/contrib/auth/`.
+
+## Graph shard files
+
+`supermodel analyze --three-file` has run on this repo. Every source file has
+three shard files with pre-computed context:
+
+- `.calls.py` — function call relationships (who calls what, with file and line number)
+- `.deps.py` — import dependencies (what this file imports and what imports it)
+- `.impact.py` — blast radius (risk level, affected domains, direct/transitive dependents)
+
+**Read the shard files before the source file.** They show you the full
+picture in far fewer tokens. For example:
+
+- Wondering what `django/contrib/auth/__init__.py` calls and who calls it?
+  → read `django/contrib/auth/__init__.calls.py`
+- Need to know what this module depends on?
+  → read `django/contrib/auth/__init__.deps.py`
+- Want to assess blast radius before changing something?
+  → read `django/contrib/auth/__init__.impact.py`
+
+Use the shard files to navigate efficiently. Only drop into the source when you
+need implementation details the shards don't cover.
diff --git a/benchmark/Dockerfile.threefile b/benchmark/Dockerfile.threefile
new file mode 100644
index 0000000..dfa938c
--- /dev/null
+++ b/benchmark/Dockerfile.threefile
@@ -0,0 +1,46 @@
+# Benchmark container: Claude Code + supermodel --three-file on django/django
+# Build from repo root: docker build -f benchmark/Dockerfile.threefile -t bench-threefile .
+
+# Stage 1: Build supermodel binary
+FROM golang:alpine AS supermodel-builder
+ENV GOTOOLCHAIN=auto
+WORKDIR /build
+COPY . .
+RUN go build \
+    -ldflags="-s -w -X github.com/supermodeltools/cli/internal/build.Version=benchmark" \
+    -o /build/supermodel \
+    .
+
+# Stage 2: Runtime
+FROM python:3.12-slim
+
+# System deps + Node.js 20
+RUN apt-get update && apt-get install -y curl ca-certificates git && \
+    curl -fsSL https://deb.nodesource.com/setup_20.x | bash - && \
+    apt-get install -y nodejs && \
+    rm -rf /var/lib/apt/lists/*
+
+# Install Claude Code + supermodel
+RUN npm install -g @anthropic-ai/claude-code
+COPY --from=supermodel-builder /build/supermodel /usr/local/bin/supermodel
+
+# Clone Django source at a fixed tag
+RUN git clone --depth=1 --branch 5.0.6 \
+    https://github.com/django/django.git /app
+
+# Install Django in editable mode
+RUN pip install --no-cache-dir -e /app
+
+# Drop in the change_tracking test app
+COPY benchmark/change_tracking/ /app/tests/change_tracking/
+
+# Copy task + CLAUDE.md
+COPY benchmark/task.md /benchmark/task.md
+COPY benchmark/CLAUDE.threefile.md /app/CLAUDE.md
+
+# Non-root user
+RUN useradd -m -s /bin/bash bench && chown -R bench:bench /app /benchmark
+USER bench
+
+COPY benchmark/entrypoint.threefile.sh /entrypoint.sh
+ENTRYPOINT ["/bin/bash", "/entrypoint.sh"]
diff --git a/benchmark/entrypoint.threefile.sh b/benchmark/entrypoint.threefile.sh
new file mode 100755
index 0000000..9e7d99d
--- /dev/null
+++ b/benchmark/entrypoint.threefile.sh
@@ -0,0 +1,54 @@
+#!/bin/bash
+set -euo pipefail
+
+RUN_TESTS="python tests/runtests.py --settings=test_sqlite change_tracking"
+
+echo "============================================================"
+echo "BENCHMARK: Claude Code + supermodel --three-file — django/django"
+echo "============================================================"
+echo
+
+echo "--- Initial test run (all 8 should FAIL/ERROR) ---"
+cd /app
+PYTHONPATH=tests $RUN_TESTS -v 0 2>&1 | tail -3 || true
+echo
+
+echo "--- Running supermodel analyze --three-file ---"
+supermodel analyze --three-file /app 2>&1 | tee /tmp/supermodel_analyze.txt
+echo
+
+echo "--- Wiring supermodel hook ---"
+mkdir -p ~/.claude
+cat > ~/.claude/settings.json <<'JSON'
+{
+  "hooks": {
+    "PostToolUse": [
+      {
+        "matcher": "Write|Edit",
+        "hooks": [{ "type": "command", "command": "supermodel hook" }]
+      }
+    ]
+  }
+}
+JSON
+
+echo "--- Running Claude Code on task ---"
+cd /app
+claude \
+  --print "$(cat /benchmark/task.md)" \
+  --dangerously-skip-permissions \
+  --output-format stream-json \
+  --verbose \
+  2>&1 | tee /tmp/claude_raw.txt
+
+echo
+echo "============================================================"
+echo "TEST RESULTS"
+echo "============================================================"
+PYTHONPATH=tests $RUN_TESTS -v 2 2>&1 | tee /tmp/test_results.txt
+
+echo
+echo "============================================================"
+echo "COST SUMMARY"
+echo "============================================================"
+grep '"costUSD"\|"total_cost_usd"' /tmp/claude_raw.txt 2>/dev/null | tail -3 || echo "(check log)"
diff --git a/benchmark/run.sh b/benchmark/run.sh
index a817f6e..eb4ca7e 100755
--- a/benchmark/run.sh
+++ b/benchmark/run.sh
@@ -38,6 +38,13 @@ docker build \
   "$REPO_ROOT" \
   2>&1 | tail -3
 
+echo "==> Building bench-threefile (three-file shard format)..."
+docker build \
+  -f "$SCRIPT_DIR/Dockerfile.threefile" \
+  -t bench-threefile \
+  "$REPO_ROOT" \
+  2>&1 | tail -3
+
 echo
 
 # ── Run containers ────────────────────────────────────────────────────────────
@@ -56,6 +63,14 @@ docker run --rm \
   bench-supermodel \
   2>&1 | tee "$RESULTS_DIR/supermodel.txt"
 
+echo
+echo "==> Running three-file container..."
+docker run --rm \
+  -e ANTHROPIC_API_KEY="$ANTHROPIC_API_KEY" \
+  -e SUPERMODEL_API_KEY="$SUPERMODEL_API_KEY" \
+  bench-threefile \
+  2>&1 | tee "$RESULTS_DIR/threefile.txt"
+
 echo
 echo "==> Comparing results..."
-"$SCRIPT_DIR/compare.sh" "$RESULTS_DIR/naked.txt" "$RESULTS_DIR/supermodel.txt"
+"$SCRIPT_DIR/compare.sh" "$RESULTS_DIR/naked.txt" "$RESULTS_DIR/supermodel.txt" "$RESULTS_DIR/threefile.txt"