odysseus-dev/odysseus · error · HTTPException

Invalid JSON: {e}

Error message

Invalid JSON: {e}

What it means

The streaming chat endpoint received a request with Content-Type application/json whose body failed to parse as JSON. json.JSONDecodeError is caught and re-raised as a 400 with the parser's message, so the exact syntax problem (position, error class) is included.

Source

Thrown at routes/chat_routes.py:876

            "model": actual_model,
            "requested_endpoint_id": requested_route.get("endpoint_id"),
            "requested_endpoint_label": requested_route.get("endpoint_label"),
            "endpoint_id": actual_route.get("endpoint_id"),
            "endpoint_label": actual_route.get("endpoint_label"),
        }

    # ------------------------------------------------------------------ #
    # POST /api/chat_stream
    # ------------------------------------------------------------------ #
    @router.post("/api/chat_stream")
    async def chat_stream(request: Request) -> StreamingResponse:
        body = None
        try:
            if request.headers.get("content-type", "").startswith("application/json"):
                try:
                    body = await request.json()
                except json.JSONDecodeError as e:
                    raise HTTPException(400, f"Invalid JSON: {e}")
        except HTTPException:
            raise
        except Exception as e:
            raise HTTPException(400, f"Request parsing error: {e}")

        _set_user_time_from_request(request)

        form_data = await request.form()
        message = form_data.get("message")
        session = form_data.get("session")
        attachments = form_data.get("attachments")
        use_web = form_data.get("use_web")
        use_research = form_data.get("use_research")
        time_filter = form_data.get("time_filter")
        preset_id = form_data.get("preset_id")
        selected_endpoint_id = str(
            form_data.get("selected_endpoint_id")
            or (body or {}).get("selected_endpoint_id")

View on GitHub (pinned to f9235ebbf1)

Solutions

1. Validate the payload with JSON.parse (JS) or json.loads (Python) before sending
2. Send with JSON.stringify(obj) / json= in requests, never a raw template string
3. Check for proxy truncation if the error position equals the end of a shortened body

Example fix

# before
requests.post(url, data=str(payload), headers={'Content-Type':'application/json'})
# after
import json
requests.post(url, data=json.dumps(payload), headers={'Content-Type':'application/json'})

const raw = JSON.stringify(payload);
try { JSON.parse(raw); } catch { fixSerialization(); return; }
await fetch(url, {method:'POST', headers:{'Content-Type':'application/json'}, body: raw});

try { await send(); } catch (e) { if (e.status === 400 && e.message.startsWith('Invalid JSON')) { console.error('payload was not valid JSON', payload); } }

When it happens

Trigger: POST /api/chat_stream with Content-Type: application/json and a malformed body: trailing commas, single quotes, unescaped newlines, truncated payload from a proxy or client bug.

Common situations: Hand-crafted curl requests with quoting mistakes; a proxy or LB truncating large bodies; client serializing form data as a string instead of JSON.stringify; encoding issues introducing BOM or control characters.

Understand the failure class

• Parsing and encoding errors: unexpected token, malformed input — why parsers reject input and how to find the real culprit.

Related errors

• text is required
• Request parsing error: {e}
• Invalid JSON
• session_id, original_text, and instruction are required
• Invalid remote_host — must be host or user@host, no SSH opti

AI-assisted analysis of odysseus-dev/odysseus@f9235ebbf1 (2026-08-14). Data as JSON: /api/errors/8c54c6691e8b9b72. Report an issue: GitHub.