Substack Author Agent

An Agno agent that uses MCP tools and Skills to help with Substack content strategy. It connects to the Substack Author MCP server for data, uses Skills for domain expertise, tracks behavior with Opik, and can be exposed as an MCP server itself via AgentOS.

Stack

Component	What	Why
Agno	Agent framework	Skills, MCPTools, AgentOS, CLI app
Claude Haiku 4.5	LLM	Fast + cheap for tool orchestration
Substack Author MCP	Remote MCP server	Articles, notes, comments, performance data
Opik + OpenTelemetry	Observability	Trace every agent run, tool call, and skill activation
AgentOS	MCP wrapper	Expose the agent as an MCP server

Skills

The agent loads 5 skills from skills/ that guide its behavior based on what you ask:

Skill	Trigger	MCP Tools Used
analyze-notes	"How are my notes doing?"	get_substack_notes
analyze-articles	"What articles worked?"	get_substack_articles, get_article_performance, get_article_content
analyze-comments	"What are readers saying?"	get_article_comments
content-ideas	"What should I write next?"	get_substack_articles, get_article_performance, get_substack_notes
brand-voice	"What's my writing style?"	get_substack_articles, get_article_content

Setup

python3 -m venv venv
source venv/bin/activate
pip install -r requirements.txt

cp .env.example .env

Edit .env:

ANTHROPIC_API_KEY=sk-ant-...
OTEL_EXPORTER_OTLP_ENDPOINT=https://www.comet.com/opik/api/v1/private/otel
OTEL_EXPORTER_OTLP_HEADERS=Authorization=<your-opik-api-key>,Comet-Workspace=default,projectName=substack-author-agent

Usage

CLI Agent

python agent.py

Talk to the agent directly. Ask about your notes, articles, comments, content ideas, or writing voice. It streams responses and keeps conversation history in-memory.

MCP Server (AgentOS)

python server.py

Exposes the agent at http://localhost:7777/mcp with a single run_agent tool. Connect it to Claude Code, Cursor, or any MCP client.

Demo

Agent CLI

User Message	Agent Response

Opik Observability

Trace Overview	Tool Calls	Skill Usage

Project Structure

substack-author-agent/
├── agent.py              # CLI agent: Skills + MCPTools + Opik
├── server.py             # AgentOS: exposes agent as MCP server
├── requirements.txt
├── .env.example
└── skills/
    ├── analyze-notes/SKILL.md
    ├── analyze-articles/SKILL.md
    ├── analyze-comments/SKILL.md
    ├── content-ideas/SKILL.md
    └── brand-voice/SKILL.md

Resources

• Agno - Agent with Skills
• Agno - Agent as MCP Server
• Opik - Agno Integration
• Agent Skills Specification