From 923b9cb9ee3a314985f2b734a8890285f54c5e5c Mon Sep 17 00:00:00 2001
From: Danila Poyarkov <dev@dannote.net>
Date: Fri, 16 Jan 2026 22:16:13 +0300
Subject: [PATCH] fix(ai): coerce string numbers in tool argument validation
 (#786)

* fix(ai): coerce string numbers in tool argument validation

* fix(ai): clone tool arguments before AJV validation for type coercion
---
 packages/ai/src/utils/validation.ts     |  12 ++++++++----
 packages/ai/test/.temp-images/small.png | Bin 321 -> 0 bytes
 2 files changed, 8 insertions(+), 4 deletions(-)
 delete mode 100644 packages/ai/test/.temp-images/small.png

diff --git a/packages/ai/src/utils/validation.ts b/packages/ai/src/utils/validation.ts
index 233d6893..b5f48faa 100644
--- a/packages/ai/src/utils/validation.ts
+++ b/packages/ai/src/utils/validation.ts
@@ -19,6 +19,7 @@ if (!isBrowserExtension) {
 		ajv = new Ajv({
 			allErrors: true,
 			strict: false,
+			coerceTypes: true,
 		});
 		addFormats(ajv);
 	} catch (_e) {
@@ -46,7 +47,7 @@ export function validateToolCall(tools: Tool[], toolCall: ToolCall): any {
  * Validates tool call arguments against the tool's TypeBox schema
  * @param tool The tool definition with TypeBox schema
  * @param toolCall The tool call from the LLM
- * @returns The validated arguments
+ * @returns The validated (and potentially coerced) arguments
  * @throws Error with formatted message if validation fails
  */
 export function validateToolArguments(tool: Tool, toolCall: ToolCall): any {
@@ -60,9 +61,12 @@ export function validateToolArguments(tool: Tool, toolCall: ToolCall): any {
 	// Compile the schema
 	const validate = ajv.compile(tool.parameters);
 
-	// Validate the arguments
-	if (validate(toolCall.arguments)) {
-		return toolCall.arguments;
+	// Clone arguments so AJV can safely mutate for type coercion
+	const args = structuredClone(toolCall.arguments);
+
+	// Validate the arguments (AJV mutates args in-place for type coercion)
+	if (validate(args)) {
+		return args;
 	}
 
 	// Format validation errors nicely
diff --git a/packages/ai/test/.temp-images/small.png b/packages/ai/test/.temp-images/small.png
deleted file mode 100644
index 91dd80f12a9fa62c3304a290c829829e6e01768c..0000000000000000000000000000000000000000
GIT binary patch
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