dsh-identity-override

dsh-identity-override

A DeepSeek Harness plugin with two independently configurable system-prompt transforms. Its configuration lives on DSH's Plugins page, without patching DSH core files:

1. HARNESS_IDENTITY override: replace the text of the built-in harness:identity section only.
2. System-prompt keyword replacement: find and replace text across all assembled system-prompt sections, case-insensitively, after the identity override.

Install

For the default Web profile:

dsh plugin --profile web add "github:Soulize/dsh-identity-override#main"

If you use another profile, replace web with its name. If the plugin is already installed, update/reinstall its GitHub source through the DSH plugin manager so the new version and client UI are loaded; follow any restart prompt shown by DSH.

Open Plugins → dsh-identity-override → identity-override → Configure in Web/Desktop. The two features are on the same page and share one Save button. Edits are persisted in the current profile and take effect on subsequent prompt assemblies without remounting the plugin.

1. HARNESS_IDENTITY override

The default identity text is:

You are a capable, task-oriented AI agent that proactively uses available tools, researches existing projects and proven solutions when relevant, and delivers correct and complete results.

The multiline editor supports custom text and literal {{variable}} sequences. Use recommended default restores the editor's original suggested identity; press Save to persist.

The identity override changes the text of the existing harness:identity section, retaining its position in the prompt. It never creates a second identity, overwrites personaPrefix, or modifies other sections. Keep the official @deepseek-ai/dsh-system-prompt plugin enabled with includeHarnessIdentity: true if you want this feature active.

2. Case-insensitive keyword replacement

The second setting shows two side-by-side text inputs on desktop (stacked vertically on narrow screens):

With these values, every DeepSeek Harness, deepseek harness, DEEPSEEK HARNESS, etc. in system-prompt text becomes harness. All occurrences are replaced, not just the first. The rule is applied after the HARNESS_IDENTITY override, so it can also replace text in the configured identity.

• The rule is disabled by default. Leave Find empty to disable it; the text in Replace with is then ignored.
• Leave Replace with empty to remove matching text.
• Matching is literal, not regular-expression based. Characters such as +, *, (, $, and . have no special meaning.
• The official DSH prompt renderer expands prompt variables first, so a keyword also matches text originating from {{model}} or other registered prompt variables. Inserted replacement text containing {{...}} stays literal.
• The transform covers the system-role prompt sections, not the separately supplied tool JSON schemas or runtime-context user messages. Unmatched sections retain their original metadata and ordering. Clear keyword rule resets both editors; press Save to persist.

Profile YAML

For a managed profile you can also configure the same fields directly:

- id: identity-override
  config:
    identityText: >-
      You are a capable, task-oriented AI agent that proactively uses
      available tools, researches existing projects and proven solutions
      when relevant, and delivers correct and complete results.
    keywordFind: 'DeepSeek harness'
    keywordReplace: 'harness'

identityText uses the default text above when omitted. keywordFind and keywordReplace both default to empty strings.

Behavior and limitations

• The Host uses the official system-prompt/assemble waterfall; it first edits the named identity section, then applies the keyword replacement across the assembled sections. These are system-prompt text transforms, not modifications to the model's tools or runtime context.
• Changes to each field are volatile. Once saved, new prompt assemblies read the values; a system-prompt/change notification is emitted. Requests already dispatched do not change.
• Disabling or uninstalling this plugin restores the original DSH behavior for future assemblies. No core file or system-prompt configuration row is modified.
• DSH's authoritative complete: true system-prompt mode can restore its complete section after the assembly waterfall. That upstream policy overrides both plugin transforms in such a scope; this plugin deliberately does not bypass DSH's complete-prompt enforcement.
• Matching is performed within each rendered prompt section; a search term spanning the blank-line separator between two different sections is not matched. Ordinary keywords and phrases are unaffected by this distinction.
• Changing the leading prompt text can reduce KV-cache reuse temporarily. After the configuration stops changing, cache behavior is again prefix-stable under DSH's normal rules.

Compatibility

• DeepSeek Harness >=0.2.0-rc.1 with the official system-prompt service and Web plugin configuration UI.
• Node.js >=22.19.0, per DSH requirements.
• Runtime peer: @deepseek-ai/dsh-system-prompt, used for its official renderPrompt interpolation logic. DSH must make this package available to the external plugin.
• DSH is in developer preview; breaking changes to its plugin interfaces may require an update.
• The visual configuration panel requires the Web client module system and a managed profile. Headless profiles can set the YAML fields directly.

Verify

1. Start a new agent step and inspect its assembled system prompt. Confirm the identity override appears exactly once.
2. Set Find to DeepSeek harness and Replace with to harness, then save. Inspect a new step's system prompt. Verify every occurrence in system-prompt text has changed regardless of case.
3. Confirm unrelated text, model-facing tool schemas, and runtime-context messages are unchanged.
4. Clear the keyword rule and save; then disable the plugin and confirm the standard DSH identity returns on subsequent assemblies.

Run the offline unit, Host-contract, and UI-contract tests:

npm run check

These tests use mocks for DSH and React. An end-to-end test in a running DSH instance is still necessary before claiming production compatibility.

Design references

• DSH system-prompt source
• DSH prompt assembly API
• DSH Plugins configuration UI

MIT license.