ox-alpha-free via zen/go/v1: any tools payload returns network_error/503 since 2026-08-23 (was working 02:55-06:11)

Summary

ox-alpha-free (also x-preview-f-free / stealth/ox-alpha) via https://opencode.ai/zen/go/v1 returns network_error / 503 Upstream request failed on any tools: payload since 2026-08-23 ~11:52 IST. Same payload without tools streams correctly. muse-spark-1.2-contributor with identical tools works — so not a Hermes User-Agent block.

Provider

• Base URL: https://opencode.ai/zen/go/v1 (OpenCode Go)
• Model: ox-alpha-free (Stealth, 1M context, free preview)
• Also repros on x-preview-f-free via same provider
• Hermes version: 0.20.5 with attribution headers User-Agent: HermesAgent/0.20.5, HTTP-Referer: https://hermes-agent.nousresearch.com, X-Title: Hermes Agent

Timeline

• 2026-08-23 02:55-06:11 IST: WORKING — Hermes session with 32 core + 53 deferred (~9798 tokens) including mcp__sequential_thinking succeeded for 390+ turns (in=217k, tool_turns=180-203, out=24-519 each)
• 2026-08-23 11:52:43 IST: FIRST FAILURE — Empty response (no content or reasoning) — retry 1/3 in 6.1s (model=ox-alpha-free) → 2/3 → 3/3 → Empty response after 3 retries. No fallback available.
• Then 12:06, 12:20, 12:25, 16:26, 16:33 — 100% fail with same pattern
• Switching to muse-spark-1.2-contributor instantly succeeds (in=36751 out=424)

Direct API repro (bypass Hermes, 2026-08-23 19:12 IST)

0 tools → OK (streams):

curl -s https://opencode.ai/zen/go/v1/chat/completions \
  -H "Authorization: Bearer $OPENCODE_GO_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"model":"ox-alpha-free","stream":true,"messages":[{"role":"user","content":"hi"}]}'
# -> data: {"delta":{"reasoning_content":"The user just said hi..."}} ... streams correctly

1 dummy tool → FAIL:

# payload: {"model":"ox-alpha-free","stream":true,"messages":[{"role":"user","content":"hi"}],"tools":[{"type":"function","function":{"name":"t","description":"test","parameters":{"type":"object","properties":{"x":{"type":"string"}},"required":[]}}}]}
curl -s https://opencode.ai/zen/go/v1/chat/completions -H "Authorization: Bearer $KEY" -H "Content-Type: application/json" -d @payload.json
# stream:  data: {"id":"...","model":"ox-alpha-free","choices":[{"index":0,"finish_reason":"network_error","delta":{"role":"assistant","content":""}}]}  data: [DONE]
# non-stream: {"error":{"type":"server_error","message":"Error from provider (Console Go): Upstream request failed: Endpoint is unavailable."}}

Same failure with:

• HermesAgent/0.20.5 UA
• OpenAI/Python 1.99.0 UA
• curl default UA
  → Not a Hermes User-Agent block

Same Hermes UA + same 1 tool on muse-spark-1.2-contributor → OK (streams Hey there!), so tool schema is valid.
Same Hermes UA + 0 tools on ox-alpha → OK, so Hermes not blocked.

Tested variants all fail with network_error:

• 1 minimal tool, only sequential_thinking, 5 tools, 20 tools, 53 tools

Hermes logs

2026-08-23 11:52:43 WARNING [20260821_224320_fad8d102] agent.conversation_loop: Empty response (no content or reasoning) — retry 1/3 in 6.1s (model=ox-alpha-free)
2026-08-23 11:52:59 WARNING ... retry 2/3 in 13.4s
2026-08-23 11:53:22 WARNING ... retry 3/3 in 25.4s
2026-08-23 11:53:59 WARNING ... Empty response after 3 retries. No fallback available. model=ox-alpha-free provider=opencode-go
2026-08-23 12:06:23 WARNING ... HTTP 503: Upstream request failed: Endpoint is unavailable.

Related issues

• lidge-jun/opencodex#2423 — OpenRouter Ox Alpha empty completion (filed Aug 23, same symptom sendCount:1 no recovery)
• earendil-works/pi#8473 — ox-alpha-free missing finish_reason with tools via zen/go/v1
• anomalyco/opencode#36889 / #37231 — zen/go frequent 503 / 000 outages

Expected

Any tools: payload should return either tool calls or text, not network_error/empty. Hermes always sends tools (32+53), so ox-alpha-free is currently unusable in any agentic harness.

Environment

• Hermes Agent 0.20.5, OpenCode Go zen/go/v1, reasoning_effort: max (also repros with low)
• Tested from TrueNAS Hermes host (Tailscale) + direct curl

Start by reproducing the reported requests against https://opencode.ai/zen/go/v1/chat/completions: run the zero-tools and one-tool curl payloads for ox-alpha-free, then compare the same tool request with muse-spark-1.2-contributor. Done means tool-bearing requests no longer return network_error, an empty response, or HTTP 503; the issue does not name a repository file or test.