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Custom OpenAI-compatible provider returns no text content #5210
Description
Description
Summary
When using a custom provider with @ai-sdk/openai-compatible, API calls complete successfully but no text content is displayed. The API returns valid responses (verified via curl), but opencode shows empty responses with 0 tokens.
Dedalus API: https://docs.dedaluslabs.ai/api
Environment
- opencode version: 1.0.134
- OS: macOS (darwin arm64)
Config
{
"$schema": "https://opencode.ai/config.json",
"provider": {
"dedalus-labs": {
"npm": "@ai-sdk/openai-compatible",
"name": "Dedalus Labs",
"options": {
"baseURL": "https://api.dedaluslabs.ai/v1"
},
"models": {
"openai/gpt-5-mini": {
"name": "GPT-5 Mini"
},
"google/gemini-2.5-flash": {
"name": "Gemini 2.5 Flash"
}
}
}
}
}Symptoms
- API calls complete (shows ~2s completion time in UI)
- No text content is displayed
- Session data shows
finish: "stop"but no text parts - Token counts show
input: 0, output: 0 - No error is displayed
API Works Correctly
Direct curl test confirms the API returns valid streaming responses:
curl -s "https://api.dedaluslabs.ai/v1/chat/completions" \
-H "Authorization: Bearer $API_KEY" \
-H "Content-Type: application/json" \
-d '{"model": "openai/gpt-5-mini", "messages": [{"role": "user", "content": "Say hi"}], "stream": true}'Returns valid SSE stream:
data: {"choices":[{"delta":{"content":"Hi"}}]}
data: {"choices":[{"delta":{},"finish_reason":"stop"}],"usage":{...}}
data: [DONE]
Likely Cause
The @ai-sdk/openai-compatible package may not be emitting text-start events before text-delta events. In processor.ts, text-delta handling requires currentText to be set (which happens in text-start):
case "text-delta":
if (currentText) { // <-- undefined without text-start
currentText.text += value.text
...
}
breakWithout a text-start event, all text-delta events are silently ignored.
Session Data
Stored message shows completion but no content:
{
"finish": "stop",
"tokens": {
"input": 0,
"output": 0,
"reasoning": 0,
"cache": { "read": 0, "write": 0 }
}
}No text parts are created - only step-start and step-finish parts exist.
OpenCode version
1.0.134
Steps to reproduce
- Add opencode.json
- add Dedalus api key ( "dedalus-labs", using opencode auth login > Other ) (if you dm me on x I will provide you one https://x.com/cgilly2fast)
- Pick a dedalus model
- Send "Hello"
Screenshot and/or share link
Operating System
macOS 15.5 (24F74) (darwin arm64) M1 mac
Terminal
VSCode terminal
Activity
github-actions commentedon Dec 7, 2025
This issue might be a duplicate of existing issues. Please check:
Both issues use the @ai-sdk/openai-compatible provider and report content not being displayed despite successful API calls. The symptoms and likely root cause (missing
text-startevents beforetext-deltaevents) suggest these could be related issues.Feel free to ignore if your case is specific to the Dedalus Labs provider.
rekram1-node commentedon Dec 8, 2025
Hm every other provider i've seen emits them correctly, it seems like it'd be a bug on the provider side rather than the sdk no?
cgilly2fast commentedon Dec 8, 2025
I am not 100% sure thats the issue, I was trying help with beginning deductions
fix: use custom OpenAI-compatible provider to resolve empty responses
Delqhi commentedon Mar 7, 2026
This looks very close to the same custom-provider compatibility gap we hit.
We got a working fix in a fork by adding an opt-in compatibility layer for OpenAI-compatible providers:
function_callnormalization<tool_call>payloadstools/tool_choice->functions/function_callon endpoints that only partially implement the OpenAI schemafinish_reason=stopThat turned a previously blank / one-shot custom-provider session into a usable multi-turn tool flow on our side.
Related issues: #234, #15756, #10573.
If useful, I can package the compatibility layer as an explicit custom-provider config path instead of changing default native-provider behavior.
jogoossens commentedon Mar 8, 2026
have it too on our side