TUTORIAL•3 MIN READ

DeepSeek Harness Common Errors: The Official Troubleshooting Table

UPDATED: AUG 16, 2026•AUTHOR: INDEPENDENT FAN GUIDE

OVERVIEW

Fix DeepSeek Harness errors fast: MISSING_CREDENTIAL, UNKNOWN_MODEL, image refusals, install gotchas, and where to report bugs (Discussions, not Issues).

Before You Debug

DeepSeek Harness is a developer preview, and the official README is explicit: THERE WILL BE COMPATIBILITY-BREAKING CHANGES^[1]. If a fresh install misbehaves, check your version first — old early rcs (0.0.1-rc.5) shipped bundled components that were later removed, and may not match current docs^[2].

The repo has GitHub Issues disabled and accepts no external PRs. Bug reports and help live in GitHub Discussions and the community Discord — search there before filing^[1]^[3].

NOTE

Rule of thumb: pin a current rc, and after any upgrade, re-run your critical workflows. Breaking changes are expected during the preview window.

MISSING_CREDENTIAL

You have not stored a provider key. The harness cannot authenticate to the model API^[4].

Fix: open Settings → Models and save the provider key for the model in use
Alternative: set the corresponding environment variable the provider expects
Keys live in $DSH_HOME/.credentials.yaml and are write-only after save — re-enter rather than edit

NOTE

Custom providers (company gateway, self-hosted endpoint) need their credential saved through the same flow — a bare key in the YAML is not enough^[4].

UNKNOWN_MODEL & Fetch 401

UNKNOWN_MODEL means the model you selected is not among the configured models for the active provider. The 401 variant appears when fetching the model list^[4].

UNKNOWN_MODEL: pick a configured model, or add the missing model to the provider's model list
Fetch models → 401: your key is wrong, or the endpoint does not support GET /models — if so, add models manually

example_code.py

# Add a custom model manually in $DSH_HOME/settings.yaml
llm-pi-ai:
  providers:
    my-gateway:
      api: openai-completions
      baseURL: https://gateway.example/v1
      models:
        - id: legacy-chat
        - id: vision-preview
          input: [text, image]

Image Requests Refused

Your model rejected an image you sent. In dsh, models are text-only by default unless they declare image input^[4].

Model refuses images: declare image modality — input: [text, image] on the model entry
Provider rejects the request anyway: the endpoint does not actually support images — remove the image declaration and start a new session
Vision models in the ecosystem: liustack/modlens is the community's first vision bridge plugin^[5]

NOTE

After any model config change, open a fresh session — modality declarations apply per session^[4].

Install & Launch Gotchas

Community hands-on reports plus the docs surface four recurring setup traps^[1]^[3]^[6].

npm route requires Node.js installed first
Source builds need pnpm and a completed pnpm run build — production runs require built artifacts
The dsh process uses its launch directory as the filesystem root; launching from the wrong directory = empty workspace. Choose the workspace explicitly in the Web UI
Headless failures exit non-zero; the exit code distinguishes command, config, and startup failures — scriptable, but read the logs

NOTE

A 30-second install is the norm — the rough edges are mostly version drift and workspace selection, not the product itself^[6].

Where to Get Help

When the official table does not cover your case, the community channels are the source of truth^[1]^[3].

Deep dive first: the tutorial walks a full working setup, and the Web UI guide explains workspaces and the Trajectory view that make most 'weird behavior' debuggable in minutes.

GitHub Discussions — official channel for bugs and questions (Issues are disabled)
Community Discord — real-time help
open-harness.net — independent complete guide with a troubleshooting section
deepseekharness.io — plugin index and community resources

REFERENCES