Skip to content

Subject: Sub-agent 120s API timeout renders agent_open nearly unusable (v0.8.39) #1806

@qiyuanlicn

Description

@qiyuanlicn

I'm running DeepSeek TUI v0.8.39 on Windows. I attempted to use parallel sub-agents (agent_open) to convert a 280-line Chinese biobanking standard into SOP documents — exactly the kind of parallel task offload that sub-agents are advertised for. All 5 sub-agents failed identically:

status: Failed: "API call timed out after 120s"
duration_ms: 731,203   (actual runtime: 12+ minutes)
steps_taken: 0
result: null

What's happening: The sub-agent does the work — it runs for 12 minutes — but the DeepSeek API terminates the response stream at 120s. Since sub-agents have allowed_tools: [] (no write access) and must return all output through the API response body, any task requiring more than ~30 seconds of generation is silently killed. The sub-agent has no way to checkpoint intermediate results or write them to disk.

Reproduction (trivial): Launch any sub-agent with a prompt that requires generating more than a few hundred words of output. It will time out. Lightweight tasks (read a file, return one line — ~30s) succeed. Anything substantive fails.

Impact: Sub-agents in their current form are limited to parallel read-only reconnaissance — grep, count, one-line summaries. They cannot be used for document generation, multi-step reasoning, code refactoring, or any task where output exceeds what fits in 120s of generation. This defeats the primary value proposition of sub-agent task offload.

Comparison with other tools in the same TUI:

Tool                 Timeout                         Configurable    Can write files
─────────────────────────────────────────────────────────────────────────────────
task_shell_start     user-defined (up to 600s)       Yes             Yes
rlm_eval sub-query   configurable via rlm_configure  Yes             Yes (Python)
agent_open           hardcoded 120s                  No              No

What's needed:

  1. Configurable sub-agent API timeout — expose in config.toml under [subagents] (suggested: default 600s, max 1800s). This is the minimum fix.

  2. Write-tool access for sub-agents — let sub-agents use write_file so large results can be persisted to disk instead of squeezed through the API response pipe. Combined with the parent reading the file, this bypasses the response-size constraint entirely.

  3. Streaming or intermediate checkpoint support — sub-agents should be able to report partial results before the final response, or the parent should be able to poll intermediate state.

Without at least #1, sub-agents are a demo feature, not a production tool. With a 120s ceiling, they add parallelism overhead (spawn + context transfer) to tasks that are faster to run sequentially in the parent session.

Summary: The current agent_open implementation is bottlenecked by a server-side 120s API response limit with no local escape hatch. This makes sub-agents useless for any real workload. Please prioritize exposing the timeout configuration and granting sub-agents write-tool access.

Metadata

Metadata

Assignees

No one assigned

    Labels

    bugSomething isn't workingenhancementNew feature or request

    Projects

    Status
    In progress

    Milestone

    Relationships

    None yet

    Development

    No branches or pull requests

    Issue actions