diff --git a/claudetool/think.go b/claudetool/think.go
new file mode 100644
index 0000000..293cc0b
--- /dev/null
+++ b/claudetool/think.go
@@ -0,0 +1,39 @@
+package claudetool
+
+import (
+	"context"
+	"encoding/json"
+
+	"sketch.dev/ant"
+)
+
+// The Think tool provides space to think.
+var Think = &ant.Tool{
+	Name:        thinkName,
+	Description: thinkDescription,
+	InputSchema: ant.MustSchema(thinkInputSchema),
+	Run:         thinkRun,
+}
+
+const (
+	thinkName        = "think"
+	thinkDescription = `Think out loud, take notes, form plans. Has no external effects.`
+
+	// If you modify this, update the termui template for prettier rendering.
+	thinkInputSchema = `
+{
+  "type": "object",
+  "required": ["thoughts"],
+  "properties": {
+    "thoughts": {
+      "type": "string",
+      "description": "The thoughts, notes, or plans to record"
+    }
+  }
+}
+`
+)
+
+func thinkRun(ctx context.Context, m json.RawMessage) (string, error) {
+	return "recorded", nil
+}