Add-ons extend Markster OS with proprietary data and intelligence that is not available in the open-source layer.
Free skills call public or open APIs, or require no API at all. All six skills in this OS are free and fully functional without any add-on key.
Paid add-ons extend the skills with proprietary data - verified contact lists, event attendee intelligence, AI visibility scoring. When you set the add-on API key, the skill detects it and unlocks the additional functionality.
The base workflow always works. Add-ons make specific steps faster or more powerful.
All add-ons follow the same pattern:
Step 1: Get a key
Sign up at markster.ai/addons. Each add-on has its own page with pricing and a free tier (where available).
Step 2: Set the environment variable
export AOE_GRADER_KEY="your_key_here"
export EVENT_SCOUT_KEY="your_key_here"
export LEAD_PACKS_KEY="your_key_here"Add to your shell profile for persistence.
Step 3: Restart Claude / Codex / Gemini
The skill reads the environment variable on load. Restart your AI environment after setting the key.
Step 4: Confirm activation
In your AI environment, type the skill command (e.g., /cold-email). The skill will confirm which add-ons are active.
| Add-on | Key | Free tier | Paid plans | Details |
|---|---|---|---|---|
| AOE Grader | AOE_GRADER_KEY |
1 audit/month | From $49/month | README |
| Event Scout | EVENT_SCOUT_KEY |
10 events/month | From $79/month | README |
| Lead Packs | LEAD_PACKS_KEY |
None | Per pack | README |
The following add-ons are in development or planning:
- Intent signals - real-time buying intent data for your ICP segment
- Podcast intelligence - who is guesting on podcasts your ICP listens to
- LinkedIn enrichment - additional data fields from LinkedIn for contact enrichment
To request an add-on, contact hello@markster.ai or open a GitHub issue.
Add-on support: addons@markster.ai General questions: hello@markster.ai