opencode web: child session created with ?directory= returns empty body on POST /session/{id}/message #12271
Description
Bug Description
In opencode web mode, child sessions created via POST /session?directory=/path return HTTP 200 with Content-Length: 0 (empty body) on subsequent POST /session/{id}/message calls. Child sessions created without the directory query parameter work correctly.
Environment
- OpenCode: 1.1.51
- Mode:
opencode web - Platform: Linux x86_64
Steps to Reproduce
AUTH="Basic $(echo -n 'opencode:<password>' | base64)"
PARENT="<any_existing_session_id>"
# 1. Create child session WITH directory
CHILD=$(curl -s -H "Authorization: $AUTH" -H "Content-Type: application/json" \
-X POST "http://localhost:4096/session?directory=/home/user/project" \
-d "{\"parentID\": \"$PARENT\"}")
CHILD_ID=$(echo $CHILD | python3 -c "import sys,json; print(json.load(sys.stdin)['id'])")
# 2. Send prompt — returns empty body
curl -v -H "Authorization: $AUTH" -H "Content-Type: application/json" \
-X POST "http://localhost:4096/session/$CHILD_ID/message" \
-d '{"agent":"sisyphus-junior","parts":[{"type":"text","text":"hello"}]}'
# → HTTP 200, Content-Length: 0, empty bodyComparison: Without directory
# Create child session WITHOUT directory
CHILD2=$(curl -s -H "Authorization: $AUTH" -H "Content-Type: application/json" \
-X POST "http://localhost:4096/session" \
-d "{\"parentID\": \"$PARENT\"}")
CHILD2_ID=$(echo $CHILD2 | python3 -c "import sys,json; print(json.load(sys.stdin)['id'])")
# Send prompt — returns full response
curl -s -H "Authorization: $AUTH" -H "Content-Type: application/json" \
-X POST "http://localhost:4096/session/$CHILD2_ID/message" \
-d '{"agent":"sisyphus-junior","parts":[{"type":"text","text":"hello"}]}'
# → HTTP 200, body = 1261 bytes (valid JSON)Controlled Experiment Results
Only variable changed is the directory parameter. Everything else (parent session, prompt body, auth) is identical:
POST /session → prompt ✅ body=1261 bytes
POST /session?directory=/home/user/project → prompt ❌ body=0 bytes
POST /session?directory=/home/user → prompt ❌ body=0 bytes
Impact
The oh-my-opencode plugin passes directory when creating subagent sessions to ensure subagents operate in the correct project directory. This bug causes delegate_task (and call_omo_agent, look_at) to fail 100% of the time in opencode web mode. TUI mode is unaffected (presumably uses in-process transport rather than HTTP).