ResultMessage is being sent while background agent is still working and turn is finished

[jerbob92]

I'm using the SDK in streaming mode (calling client.query() and client.receive_response()), somewhere between 0.2.110 and 0.2.121, the behavior of the Agent SDK broke for me.

Before, it would only send the ResultMessage at the complete end of the turn. However, I now notice behavior where a background agent is still running, but the ResultMessage has already been delivered and the client.query() already returned, this causes the Agent SDK to miss messages when the background agent finishes.

[jerbob92]

After trying different versions, I think this started to break since version v0.2.111

[jerbob92]

I have fixed this by adding this to the env option:

"CLAUDE_CODE_DISABLE_BACKGROUND_TASKS": "1",

[aaronf-canva]

I am facing this exact same issue.

[jayeshjain1996]

Facing the same issue and passed CLAUDE_CODE_DISABLE_BACKGROUND_TASKS directly in env of ClaudeAgentOptions(Attached Code Snippet below for your reference) but that is not solving the problem
Can anyone help me what other ways Apart from downgrading version I can try to solve this issue
FYI downgrading the version to 0.2.110 solved the problem

Code Snippet:

ClaudeAgentOptions(
cwd=str(self.project_root),
setting_sources=["project"],
allowed_tools=self.allowed_tools,
mcp_servers=self.mcp_servers,
output_format=(
{"type": "json_schema", "schema": output_schema}
if output_schema
else None
),
# Full os.environ carries TLS vars set by config.py / setup-tls-env.sh
# (REQUESTS_CA_BUNDLE, GRADLE_OPTS, JAVA_TOOL_OPTIONS, GIT_SSL_CAINFO, ...).
env={
# "NODE_TLS_REJECT_UNAUTHORIZED": "0",
**dict(os.environ),
"CLAUDE_CODE_DISABLE_BACKGROUND_TASKS":"1",
"BASH_DEFAULT_TIMEOUT_MS":"1200000",
"BASH_MAX_TIMEOUT_MS":"2400000"
},
permission_mode="bypassPermissions",
model=self.model,
include_partial_messages=True,
)