hermes - 💡(How to fix) Fix No preflight size check before DeepSeek API calls — silent 400 on bodies over ~880KB [1 pull requests]

Describe the bug

Hermes has no local preflight check on request body size before sending to the DeepSeek API. DeepSeek returns a 400 error on JSON request bodies exceeding approximately 880KB, with no clear error message explaining the cause. From the user perspective the agent simply fails with a cryptic API error.

Reproduction

1. Run a long coding session with Eve (deepseek-v4-pro) involving large file reads and many tool outputs
2. As conversation history grows, the request body approaches and exceeds ~880KB
3. DeepSeek returns a 400 — no explanation, no recovery

Expected behaviour

Before sending the API request, Hermes should measure the serialised request body size. If it approaches the ~880KB limit, it should either:

• Trigger context compression proactively, or
• Surface a clear message: "Context too large for DeepSeek API — compressing before retry"

Actual behaviour

The oversized request is sent, DeepSeek returns a 400, and the agent fails with no actionable feedback.

Why this matters

Agents with high context usage are most at risk:

• Long sessions with large file reads (e.g. 100K char file read limit)
• Many tool call outputs accumulated in history
• High max_turns configurations (e.g. 60 turns)

The failure is silent and confusing — nothing in the UI or logs indicates the request was too large.

Suggested fix

Add a serialised body size check in the transport layer (e.g. ) before the API call. If size exceeds a configurable threshold (default ~800KB), trigger compression or raise a descriptive error.

Environment

• Provider: DeepSeek (direct, )
• Model: deepseek-v4-pro
• Platform: api_server / CLI