diff --git a/install.sh b/install.sh
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+++ b/install.sh
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+#!/usr/bin/env bash
+# install.sh — Install Developer Intelligence globally for Claude Code.
+# Run once. Works in any repo after that.
+
+set -euo pipefail
+
+SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
+CLAUDE_DIR="$HOME/.claude"
+
+mkdir -p "$CLAUDE_DIR"
+
+# Install global MCP config
+# Merge with existing if present
+MCP_FILE="$CLAUDE_DIR/mcp.json"
+if [ -f "$MCP_FILE" ]; then
+    echo "[install] Existing mcp.json found — merging..."
+    python3 -c "
+import json, sys
+existing = json.load(open('$MCP_FILE'))
+existing.setdefault('mcpServers', {})
+existing['mcpServers']['dev-intel'] = {
+    'command': 'uv',
+    'args': ['run', 'python', 'mcp_server.py'],
+    'cwd': '$SCRIPT_DIR'
+}
+json.dump(existing, open('$MCP_FILE', 'w'), indent=2)
+print('  Added dev-intel to existing mcp.json')
+"
+else
+    cat > "$MCP_FILE" << EOF
+{
+  "mcpServers": {
+    "dev-intel": {
+      "command": "uv",
+      "args": ["run", "python", "mcp_server.py"],
+      "cwd": "$SCRIPT_DIR"
+    }
+  }
+}
+EOF
+    echo "[install] Created $MCP_FILE"
+fi
+
+# Install global CLAUDE.md (append if exists)
+CLAUDE_MD="$CLAUDE_DIR/CLAUDE.md"
+MARKER="## Developer Intelligence Knowledge Graph"
+
+if [ -f "$CLAUDE_MD" ] && grep -q "$MARKER" "$CLAUDE_MD"; then
+    echo "[install] Developer Intelligence already in $CLAUDE_MD — skipping."
+else
+    cat >> "$CLAUDE_MD" << 'EOF'
+
+## Developer Intelligence Knowledge Graph
+
+This environment has access to a knowledge graph of LLM-generated documentation for your codebase via MCP tools.
+
+**Always prefer the knowledge graph over reading raw files when answering questions about what code does or how files interact.**
+
+### Query patterns
+- "What does X do?" → `get_file_doc("path/to/file.go")`
+- "How do X and Y interact?" → `get_relationship("file_a.go", "file_b.go")`
+- "What's this project about?" → `get_repo_overview()`
+- "What depends on X?" / "What breaks if I change X?" → `get_dependents("path/to/file.go")`
+- "What does X depend on?" → `get_dependencies("path/to/file.go")`
+- "Find anything about routing" → `search_docs("routing")`
+- "What's outdated?" → `get_stale_docs()`
+
+### Staleness
+Docs flagged `[STALE]` mean the code changed but the doc hasn't been regenerated yet. Mention this to the user.
+
+### Tips
+- Start broad (`get_repo_overview`) then drill into specifics.
+- `get_dependents` is impact analysis — "what breaks if I change this?"
+- File paths are relative to repo root (e.g., `echo.go`, `middleware/compress.go`).
+EOF
+    echo "[install] Appended Developer Intelligence instructions to $CLAUDE_MD"
+fi
+
+echo ""
+echo "[install] Done. Developer Intelligence is now available in all Claude Code sessions."
+echo "[install] Run 'claude' from any repo directory — the knowledge graph tools are global."