Fix DeepSeek Harness Web UI issues: CLI works but Web UI doesn't

DeepSeek Harness Web UI issues come in three typical groups: skills working in the CLI but not the Web UI (profile capability mismatch), crypto.randomUUID is not a function followed by a missing Composer input box (plain HTTP outside a secure context disables Web Crypto), and skill search that keeps missing (prefix-only matching). Fix them in this order: use HTTPS/localhost → align the profile → search by prefix → repair image references.

DeepSeek Harness Web UI issues: the three symptoms

The three symptoms differ: a skill difference is a configuration problem, a missing input box is a secure-context problem, and a failed search is a matching-rule problem. One by one (source: dshbase troubleshooting):

1. Skills work in CLI but not the Web UI — the skill works in the terminal but disappears or is unusable in the browser, common when both the CLI and the Web UI are used;
2. crypto.randomUUID is not a function + missing Composer input box — opening the page over plain HTTP by IP shows this error in the console, then the input box fails to render and cannot accept text (source: Discussion #4653);
3. Skill search misses — typing a keyword in the skill menu finds nothing, or the list only shows a few prefix-matching entries;
4. All three can be mistaken for "the Web UI is broken", but the fixes are different — match the symptom first.

Why DeepSeek Harness Web UI fails: plain HTTP breaks Web Crypto, profile mismatch, prefix search

Four root causes: plain HTTP disables Web Crypto (missing input box); the CLI and the Web UI read different profiles (skill mismatch); skill search is prefix-only (misses); Markdown image references are broken (images do not render). In detail:

1. Plain HTTP disables Web Crypto — crypto.randomUUID() only exists in a secure context: https://, or http://localhost / http://127.0.0.1; accessing by IP over plain HTTP (e.g. http://192.168.1.50:3080) is not a secure context and crypto.randomUUID is undefined (source: MDN), so the frontend script crashes and the Composer input box disappears;
2. Profile capability mismatch — skills are provided by plugins under a profile; if the CLI and the Web UI read different profiles, their capabilities differ (source: dshbase troubleshooting);
3. Skill search is prefix-only — the search filters by name prefix, so a middle word, an alias or a localized name misses;
4. Broken Markdown image references — a wrong relative path, a moved or deleted file, or a dead external link prevents images from rendering (source: dshbase troubleshooting).

Fix DeepSeek Harness Web UI: HTTPS/localhost, align profile, search by prefix

Route by symptom: a missing input box means change how you access, a skill mismatch means align the profile, a failed search means use a prefix, and missing images mean repair the reference. Step by step:

1. Use HTTPS or localhost (fixes crypto.randomUUID and the missing input box):
   • Local use: open http://localhost:3080 or http://127.0.0.1:3080 — these are secure contexts;
   • Remote use: put an HTTPS reverse proxy in front of dsh web (e.g. Nginx with a certificate), or use SSH port forwarding and access http://localhost:3080;
   • After refreshing the page the input box returns and the error disappears (source: Discussion #4653).
2. Align the profile (fixes skills working in CLI but not the Web UI):
   bash

   # Explicitly use the web profile in the CLI and retry the skill
   dsh --profile web
   

   • Confirm the Web UI is on the same profile as the CLI; switch if not;
   • Confirm the plugins under that profile are installed and activated, then restart the web service: press Ctrl+C in the terminal and run dsh web again.
3. Search skills by prefix (fixes the failed search) — search the first letters of the skill name, e.g. mcp for MCP skills; if you do not know the exact name, browse the skill list page by page instead of relying on search.
4. Repair Markdown image references (fixes missing images) — check the referenced path:
   • Relative path: confirm the image is reachable from the current file's directory;
   • Absolute path: confirm the file exists on disk;
   • External link: confirm the URL is reachable; refresh the page after fixing.

How to verify a DeepSeek Harness Web UI feature fix: access method, profile, and skill regression

Three checks confirm the fix: the access method is a secure context, the profile matches the CLI, and skills and images are back — only when all three pass is it fixed. In order:

1. Confirm the access method is a secure context — the browser address bar should show https://, http://localhost:3080 or http://127.0.0.1:3080; over plain HTTP by IP, the crypto.randomUUID error will reappear.

2. No console errors — open DevTools (F12) → Console and refresh; no more crypto.randomUUID is not a function, and the Composer input box renders normally.

3. Confirm the profile matches — explicitly use the web profile in the CLI and check the profile shown at the top of the Web UI:

   bash

   dsh --profile web
   dsh plugin --profile web list
   

   Both pointing at the same profile with a complete, activated plugin list means the skill mismatch is gone.

4. Skill regression — a prefix search in the skill menu (e.g. mcp) hits, and invoking the skill responds normally.

5. Image rendering check — pages with image references render after refresh; if not, walk through step 4 of the fix section and check paths and external links.

Notes: DeepSeek Harness Web UI — match the symptom first

1. If the input box disappears, change the access method first — do not rush to reinstall; crypto.randomUUID is a secure-context problem, not an installation problem.
2. If skills differ between the CLI and the Web UI, align the profile first, then check plugin activation.
3. Prefix-only skill search is by design; a failed search does not mean the skill is not installed.
4. Skills come from plugins — to install more, browse the curated community catalog in the DSH Plugin Hub and install with one click.
5. See install error troubleshooting for other DeepSeek Harness install errors.

Sources: dshbase troubleshooting, deepseek-harness Discussion #4653, Mozilla MDN Secure contexts, DeepSeek Harness apps/web