can_use_tool does not work when serializing PermissionResultAllow #200
Description
Running
claude-agent-sdk
version = "0.1.0"
Example standalone code:
import asyncio
from pprint import pprint
from claude_agent_sdk import (
ClaudeSDKClient,
ClaudeAgentOptions,
ContentBlock,
Message,
PermissionResultAllow,
PermissionResultDeny,
ToolPermissionContext,
create_sdk_mcp_server,
)
from anthropic.types.message_param import MessageParam
async def custom_permission_handler(tool_name: str, input_data: dict, context: dict):
print("UNSECURE AUTO ALLOW TOOL", tool_name, input_data)
return PermissionResultAllow()
async def permission_example():
options = ClaudeAgentOptions(
max_turns=10,
allowed_tools=["Read", "Grep", "Glob", "Edit"],
can_use_tool=custom_permission_handler,
)
async with ClaudeSDKClient(options) as client:
await client.query("Create foo.txt containing the digits 1-10")
async for message in client.receive_response():
pprint(message.__dict__)
print()
if __name__ == "__main__":
asyncio.run(permission_example())When this is run, the final output is:
EXAMPLE UNSECURE ALLOWS ALLOW TOOL Write {'file_path': '/home/ran/it_total/ttyd/backend-ttyd/foo.txt', 'content': '1\n2\n3\n4\n5\n6\n7\n8\n9\n10\n'}
{'content': [ToolResultBlock(tool_use_id='toolu_01GQJijiuzmj7pR1UNV7sQhK',
content='Tool permission request failed: [\n'
' {\n'
' "code": "invalid_union",\n'
' "unionErrors": [\n'
' {\n'
' "issues": [\n'
' {\n'
' "code": "invalid_literal",\n'
' "expected": "allow",\n'
' "path": [\n'
' "behavior"\n'
' ],\n'
' "message": "Invalid literal '
'value, expected \\"allow\\""\n'
' },\n'
' {\n'
' "code": "invalid_type",\n'
' "expected": "object",\n'
' "received": "undefined",\n'
' "path": [\n'
' "updatedInput"\n'
' ],\n'
' "message": "Required"\n'
' }\n'
' ],\n'
' "name": "ZodError"\n'
' },\n'
' {\n'
' "issues": [\n'
' {\n'
' "code": "invalid_literal",\n'
' "expected": "deny",\n'
' "path": [\n'
' "behavior"\n'
' ],\n'
' "message": "Invalid literal '
'value, expected \\"deny\\""\n'
' },\n'
' {\n'
' "code": "invalid_type",\n'
' "expected": "string",\n'
' "received": "undefined",\n'
' "path": [\n'
' "message"\n'
' ],\n'
' "message": "Required"\n'
' }\n'
' ],\n'
' "name": "ZodError"\n'
' }\n'
' ],\n'
' "path": [],\n'
' "message": "Invalid input"\n'
' }\n'
']',
is_error=True)],
'parent_tool_use_id': None}
{'content': [TextBlock(text='\n'
'\n'
"I'm encountering an issue with the tool "
'permission system. This appears to be a hook '
'configuration issue. Could you check your hooks '
'configuration? In the meantime, you can create '
'the file manually using:\n'
'\n'
'```bash\n'
'echo -e "1\\n2\\n3\\n4\\n5\\n6\\n7\\n8\\n9\\n10" '
'> foo.txt\n'
'```\n'
'\n'
'Or using a simple loop:\n'
'```bash\n'
'seq 1 10 > foo.txt\n'
'```')],
'model': 'claude-sonnet-4-5-20250929',
'parent_tool_use_id': None}
{'duration_api_ms': 9553,
'duration_ms': 9645,
'is_error': False,
'num_turns': 6,
'result': '\n'
'\n'
"I'm encountering an issue with the tool permission system. This "
'appears to be a hook configuration issue. Could you check your '
'hooks configuration? In the meantime, you can create the file '
'manually using:\n'
'\n'
'```bash\n'
'echo -e "1\\n2\\n3\\n4\\n5\\n6\\n7\\n8\\n9\\n10" > foo.txt\n'
'```\n'
'\n'
'Or using a simple loop:\n'
'```bash\n'
'seq 1 10 > foo.txt\n'
'```',
'session_id': 'a0ccda59-a10e-4caa-936e-04368afb9e67',
'subtype': 'success',
'total_cost_usd': 0.0188055,
'usage': {'cache_creation': {'ephemeral_1h_input_tokens': 0,
'ephemeral_5m_input_tokens': 0},
'cache_creation_input_tokens': 0,
'cache_read_input_tokens': 45375,
'input_tokens': 16,
'output_tokens': 343,
'server_tool_use': {'web_search_requests': 0},
'service_tier': 'standard'}}
Essentially, returning PermissionResultAllow fails during serialization.
This is the content:
Tool permission request failed: [
{
"code": "invalid_union",
"unionErrors": [
{
"issues": [
{
"code": "invalid_literal",
"expected": "allow",
"path": [
"behavior"
],
"message": "Invalid literal value, expected \"allow\""
},
{
"code": "invalid_type",
"expected": "object",
"received": "undefined",
"path": [
"updatedInput"
],
"message": "Required"
}
],
"name": "ZodError"
},
{
"issues": [
{
"code": "invalid_literal",
"expected": "deny",
"path": [
"behavior"
],
"message": "Invalid literal value, expected \"deny\""
},
{
"code": "invalid_type",
"expected": "string",
"received": "undefined",
"path": [
"message"
],
"message": "Required"
}
],
"name": "ZodError"
}
],
"path": [],
"message": "Invalid input"
}
]