From dd99eec4f6c1a24b11b2ca3ed9fc3432685dece3 Mon Sep 17 00:00:00 2001
From: Bryan Frimin <bryan@getprobo.com>
Date: Thu, 19 Mar 2026 10:57:31 +0100
Subject: [PATCH] Clamp pagination size in page.NewCursor

Enforce minimum (25) and maximum (100) bounds on cursor size to prevent negative values or excessively large page sizes. All three API surfaces (GraphQL, MCP, CLI) funnel through NewCursor, so the fix belongs here.

Signed-off-by: Bryan Frimin <bryan@getprobo.com>
---
 pkg/page/cursor.go      |  5 ++-
 pkg/page/cursor_test.go | 71 +++++++++++++++++++++++++++++++++++++++++
 2 files changed, 75 insertions(+), 1 deletion(-)
 create mode 100644 pkg/page/cursor_test.go

diff --git a/pkg/page/cursor.go b/pkg/page/cursor.go
index a231d7bb4..bb0fcb4cb 100644
--- a/pkg/page/cursor.go
+++ b/pkg/page/cursor.go
@@ -36,14 +36,17 @@ type (
 
 const (
 	DefaultCursorSize = 25
+	MaxCursorSize     = 100
 
 	Tail Position = "TAIL"
 	Head Position = "HEAD"
 )
 
 func NewCursor[T OrderField](size int, from *CursorKey, pos Position, orderBy OrderBy[T]) *Cursor[T] {
-	if size == 0 {
+	if size <= 0 {
 		size = DefaultCursorSize
+	} else if size > MaxCursorSize {
+		size = MaxCursorSize
 	}
 
 	return &Cursor[T]{
diff --git a/pkg/page/cursor_test.go b/pkg/page/cursor_test.go
new file mode 100644
index 000000000..1c6cb6406
--- /dev/null
+++ b/pkg/page/cursor_test.go
@@ -0,0 +1,71 @@
+// Copyright (c) 2025 Probo Inc <hello@getprobo.com>.
+//
+// Permission to use, copy, modify, and/or distribute this software for any
+// purpose with or without fee is hereby granted, provided that the above
+// copyright notice and this permission notice appear in all copies.
+//
+// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
+// REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
+// AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
+// INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
+// LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
+// OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+// PERFORMANCE OF THIS SOFTWARE.
+
+package page
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+type testOrderField string
+
+func (f testOrderField) Column() string { return string(f) }
+func (f testOrderField) String() string { return string(f) }
+
+func TestNewCursor(t *testing.T) {
+	t.Parallel()
+
+	orderBy := OrderBy[testOrderField]{
+		Field:     testOrderField("created_at"),
+		Direction: OrderDirectionAsc,
+	}
+
+	tests := []struct {
+		name         string
+		size         int
+		expectedSize int
+	}{
+		{
+			name:         "negative size defaults to DefaultCursorSize",
+			size:         -10,
+			expectedSize: DefaultCursorSize,
+		},
+		{
+			name:         "zero size defaults to DefaultCursorSize",
+			size:         0,
+			expectedSize: DefaultCursorSize,
+		},
+		{
+			name:         "valid size is kept as-is",
+			size:         50,
+			expectedSize: 50,
+		},
+		{
+			name:         "oversized value is clamped to MaxCursorSize",
+			size:         500,
+			expectedSize: MaxCursorSize,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			t.Parallel()
+
+			cursor := NewCursor[testOrderField](tt.size, nil, Head, orderBy)
+			assert.Equal(t, tt.expectedSize, cursor.Size)
+		})
+	}
+}