dsh-identity-override

A DeepSeek Harness plugin that replaces only the built-in HARNESS_IDENTITY prompt section (harness:identity) with text configured on the Plugins page. It does not modify DSH source files or prepend/append a second identity instruction.

Install

Install into the same DSH profile you normally use:

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

If you use a different profile, replace web with that profile name. Restart DSH if requested. In Web/Desktop, open Plugins -> dsh-identity-override -> identity-override -> Configure.

Enter your replacement in the multiline text field and click Save. Use recommended default fills the editor with the plugin default; click Save to persist the reset. The value is stored in the active profile, and changes apply to subsequent prompt assemblies without remounting the plugin.

Default identity

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.

You can also edit the plugin's own profile row 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.

Leave the official @deepseek-ai/dsh-system-prompt row and its includeHarnessIdentity: true setting intact. The plugin does not need to disable the official section or change personaPrefix.

How it works

• The Host plugin hooks the official system-prompt/assemble waterfall and replaces the text of the existing named section, preserving its position and every other section, context, tool schema, and variable.
• It uses interpolate: false only for that section, allowing literal {{variable}} text and multiline identity messages without strict DSH prompt-variable interpolation.
• Its settings field is volatile: saving a different value updates the active Host without a remount and emits system-prompt/change to signal the updated prompt.
• When disabled or uninstalled, the hook disappears; DSH's original identity is again used on subsequent prompt assemblies. No core files are patched.
• If the built-in identity is absent (for example, includeHarnessIdentity: false), the plugin does not inject a new section. If a scope uses complete: true, DSH's complete-prompt contract remains authoritative.
• A blank editor value cannot be saved. If an invalid value reaches the Host through external configuration, the Host uses the recommended default instead.

Changing the first system-prompt tokens can reduce prefix cache reuse across the change; a stable replacement is cache-friendly. Existing in-flight model requests are unaffected.

Compatibility

• DeepSeek Harness >=0.2.0-rc.1 (its system-prompt/assemble, Plugins config form, and client module APIs).
• Node.js >=22.19.0 for DSH.
• DSH is in developer preview and may introduce breaking plugin API changes. This plugin requires the built-in section name harness:identity.
• The config page requires DSH's Web client module system and a managed profile. No configuration page is available in headless-only deployments; the plugin still works with the profile YAML field.

Verify

1. Start a fresh agent session and inspect the assembled system prompt at the first model step. The built-in identity should appear once, with the replacement text.
2. Confirm the original You are an AI agent powered by DeepSeek Harness. is absent and other system-prompt sections remain unchanged.
3. Save a different identity through Configure, then initiate a new model step or new session and inspect the assembled prompt again.
4. Disable the plugin: the original identity should return when DSH next assembles the prompt.

Run local unit and UI-contract tests:

npm test
npm run check

These tests mock the Host service and UI framework; they do not substitute for an integration test against a running DSH installation.

Design references

• DSH system prompt source
• DSH prompt assembly API
• DSH plugin configuration UI

MIT license.