[headless] TRANSPORT: DeepSeek API stream fails on the LLM round after a tool call succeeds

[niyongsheng]

Bug: [headless] TRANSPORT — DeepSeek API stream fails on the LLM round after a tool call succeeds

Environment: dsh 0.1.0-rc.6 (dsh-llm-deepseek / dsh-headless same), macOS 26.5.2, Node v25.9.0, model deepseek-v4-flash, reasoningEffort: high, maxTokens: 256000

Reproduction

1. Install any plugin registering a tool via ctx.tools.register() into the headless profile (dsh plugin add file:<path> + insert entry in cordis.patch.yml).
2. Run a task requiring a tool call:

dsh --profile headless "调用 ocr_image 识别 /path/to/image.png，输出识别内容"

Expected

Agent completes the task after the tool result.

Actual

Step 1 succeeds (model emits tool call → tool executes → result returned), but every subsequent LLM request fails with TRANSPORT (3 retries, all fail). Pure-conversation tasks (single round, no tools) succeed.

Session log timeline (one run):

13:58:13 request/header    (turn 1 step 1)
13:58:14 finish            reason: tool-calls
13:58:14 tool/call         ocr_image {"image_url": "...png"}
13:58:15 tool/result       content: "Hello Vision 123", isError: false
13:58:15 finish            error: TRANSPORT "DeepSeek API stream from https://api.deepseek.com failed"
13:58:16 finish            error: TRANSPORT (retry)
13:58:17 finish            error: TRANSPORT (retry)

Observations

• Tool result is tiny plain text ("Hello Vision 123"); the failing request is the round that carries the tool result back to the model.
• Same task completes in the web GUI (same model/reasoning effort): 5/5 headless attempts failed, 1/1 web attempt succeeded.
• Error surfaces at the stream-consumption layer (LlmError ... "TRANSPORT", cause: error in dsh-llm-deepseek) — not an HTTP-status rejection, so the upstream cause isn't visible in the session log.

Happy to provide the full session JSONL or run with tracing if useful.