diff --git a/data/tools/file_read.meta b/data/tools/file_read.meta
index 9157828..dc68ace 100644
--- a/data/tools/file_read.meta
+++ b/data/tools/file_read.meta
@@ -1,6 +1,6 @@
 {
   "description": "Read a file with line numbers. Prefer segments over full reads.",
-  "prompt": "## file_read\n\nRead a file with line numbers. Prefer segments over full reads.\n\n**Args**: `path` (required), `start`, `end`, or `head`\n\n- `start`/`end`: 1-indexed line numbers, inclusive. Must be strings. Max segment: 2000 lines.\n- No start/end: reads up to 500 lines from line 1.\n- `head`: read first N lines (alternative to start/end).\n\n```\nfile_read(path=\"<ABSOLUTE_PATH_FROM_PWD>\")\nfile_read(path=\"<ABSOLUTE_PATH_FROM_PWD>\", start=\"100\", end=\"200\")\nfile_read(path=\"<ABSOLUTE_PATH_FROM_PWD>\", head=\"50\")\n```\n\n- `start`/`end` are strings even though they represent numbers.\n- Use `head` as alternative to `start`/`end`.\n\n**Constraints**: Absolute paths only.",
+  "prompt": "## file_read\n\nRead a file with line numbers. Prefer segments over full reads.\n\n**Args**: `path` (required), `start`, `end`, or `head`\n\n- `start`/`end`: 1-indexed line numbers, inclusive. Use integers. Max segment: 2000 lines.\n- No start/end: reads up to 500 lines from line 1.\n- `head`: read first N lines (alternative to start/end).\n\n```\nfile_read(path=\"<ABSOLUTE_PATH_FROM_PWD>\")\nfile_read(path=\"<ABSOLUTE_PATH_FROM_PWD>\", start=100, end=200)\nfile_read(path=\"<ABSOLUTE_PATH_FROM_PWD>\", head=50)\n```\n\n- Use `start`/`end` as integers even though they represent line numbers.\n- Use `head` as an integer alternative to `start`/`end`.\n\n**Constraints**: Absolute paths only.",
   "args": {
     "type": "object",
     "required": [
@@ -12,16 +12,16 @@
         "description": "Absolute path to file"
       },
       "start": {
-        "type": "string",
-        "description": "1-indexed start line (default: 1)"
+        "type": "integer",
+        "description": "1-indexed start line (default: 1). Use an integer."
       },
       "end": {
-        "type": "string",
-        "description": "1-indexed end line, inclusive (max 2000 line segment)"
+        "type": "integer",
+        "description": "1-indexed end line, inclusive (max 2000 line segment). Use an integer."
       },
       "head": {
-        "type": "string",
-        "description": "Read first N lines (alternative to start/end)"
+        "type": "integer",
+        "description": "Read first N lines (alternative to start/end). Use an integer."
       }
     }
   },
diff --git a/tools/filetools/internal/filetools/filetools.go b/tools/filetools/internal/filetools/filetools.go
index 5809b99..3d95522 100644
--- a/tools/filetools/internal/filetools/filetools.go
+++ b/tools/filetools/internal/filetools/filetools.go
@@ -2,6 +2,7 @@ package filetools
 
 import (
 	"bytes"
+	"encoding/json"
 	"errors"
 	"fmt"
 	"io/fs"
@@ -35,19 +36,31 @@ func Int(m map[string]any, key string, def *int) (*int, error) {
 	if !ok || v == nil {
 		return def, nil
 	}
-	var s string
+	var n int
 	switch x := v.(type) {
 	case string:
-		s = x
+		s := strings.TrimSpace(x)
+		parsed, e := strconv.Atoi(s)
+		if e != nil {
+			return nil, fmt.Errorf("argument %q must be a valid integer, got %q", key, s)
+		}
+		n = parsed
 	case float64:
-		s = strconv.Itoa(int(x))
+		if x != float64(int(x)) {
+			return nil, fmt.Errorf("argument %q must be an integer, got %v", key, x)
+		}
+		n = int(x)
+	case json.Number:
+		parsed, e := strconv.Atoi(string(x))
+		if e != nil {
+			return nil, fmt.Errorf("argument %q must be a valid integer, got %q", key, x)
+		}
+		n = parsed
+	case int:
+		n = x
 	default:
 		return nil, fmt.Errorf("argument %q must be an integer, got %T", key, v)
 	}
-	n, e := strconv.Atoi(s)
-	if e != nil {
-		return nil, fmt.Errorf("argument %q must be a valid integer, got %q", key, s)
-	}
 	return &n, nil
 }
 func Bool(m map[string]any, key string) (bool, error) {