Feature Request: Enhanced Prompt Customization for Advanced Tagging Workflows

First, a huge thank you!

Karakeep is an amazing self-hosted service, and the AI tagging integration is genuinely game-changing. The work you and the team put into this is seriously appreciated. Thank you for the excellent open-source work!

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Problem Statement

While using Karakeep for consolidating bookmarks with AI tagging, I encountered a limitation with prompt customization that makes it difficult to implement advanced tagging strategies (specifically, tag consolidation and deduplication):

Current Behavior:

• Base prompts are hardcoded (e.g., "Aim for a variety of tags")
• Users can only append custom rules (max 500 characters)
• When custom rules conflict with base prompts, the AI receives contradictory instructions

Example of the conflict:

Base prompt: "Aim for a variety of tags, including broad categories, specific keywords..."

User appends: "Max 4 tags. Reuse existing tags when possible." = Conflicting instructions sent to LLM

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Why This Matters

For users implementing tag consolidation strategies (reusing existing tags instead of creating new ones), the current rigid prompts make it impossible to:

• Enforce strict tag limits
• Reference existing user tags with semantic similarity checking
• Override "create variety" behavior with "consolidate effectively" behavior

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Suggested Solution

Option 1 (Recommended): Full Prompt Replacement

• Allow users to completely replace (not just append to) default prompts
• Increase character limit to 1500-2000 characters (or make it unlimited for power users)
• Keep sensible defaults, but make them overridable

Option 2: Structured Prompt Templates

• Provide sections users can override: [instructions], [rules], [examples], [output format]
• Each section has flexible length
• System combines them intelligently without conflicts

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Use Case

Desired workflow: INFERENCE_TEXT_MODEL: mistral:7b-instruct CUSTOM_TEXT_PROMPT_OVERRIDE: | Max 4 tags. Prioritize reusing from existing tags: {$userTags}. Only create NEW tag if no semantic match (80%+ similarity). Tags: lowercase, spaces only. Broad, not one-off/event-specific. Return JSON: {"tags": [...]}

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Current Workaround

Users like myself are having to build n8n/webhook proxies to intercept and replace prompts before sending to Ollama, which defeats the simplicity of self-hosted Karakeep.

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Additional Notes

• The {$userTags} placeholder is excellent and shows the architecture is designed for this
• The 500-char limit seems arbitrary for a self-hosted, open-source project
• This would be a game-changer for users implementing advanced tagging strategies

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Thank You Again

Thanks for considering this. Karakeep is genuinely fantastic, and this feature would make it even more powerful for self-hosted deployments. Keep up the amazing work!