Reddit Post Engine

Reddit Post Engine

Draft a Reddit post that fits the subreddit's culture. Optionally post it via Composio.

Critical rule: Never post without confirming subreddit rules. Never include product links in the body: put them in the first comment only if appropriate. Follow the 90/10 rule: your post should add value independent of any product mention.

Anti-spam rule: Posts that are primarily promotional will be removed and may get the account banned. The goal is to contribute to the community first. Product mentions go in the first comment, and only if the subreddit allows self-promotion.

Step 1: Setup Check

echo "GEMINI_API_KEY: ${GEMINI_API_KEY:+set}"
# Check if Composio Reddit MCP is connected
claude mcp list 2>/dev/null | grep -i reddit || echo "Composio Reddit MCP: not connected"

If GEMINI_API_KEY is missing: Stop. Tell the user: "GEMINI_API_KEY is required. Get it at aistudio.google.com. Add it to your .env file."

If Composio Reddit MCP is not connected: Continue. The skill will draft posts but skip the posting step. Inform the user: "Composio Reddit MCP not connected: I'll draft your post for manual submission. To enable direct posting, see the setup instructions in README.md."

Step 2: Gather Context

You need:

• Target subreddit (e.g., r/devops, r/startups, r/SideProject)
• What you are sharing (project, article, question, discussion, tool)
• One-sentence description of what it does
• Why it's relevant to this specific subreddit's community
• Whether you want a self-post (text) or link post

If any of these are missing, ask in one message:

"To draft your Reddit post, I need:

1. Which subreddit? (e.g., r/devops, r/startups)
2. What are you sharing? (project, article, tool, question)
3. What does it do? (one sentence, technical)
4. Why does this subreddit care about it specifically?"

Step 3: Fetch Subreddit Rules and Culture

Fetch the subreddit's rules:

curl -s \
  -H "User-Agent: varnan-skills/1.0" \
  "https://www.reddit.com/r/{SUBREDDIT}/about/rules.json" \
  | python3 -c "
import sys, json
d = json.load(sys.stdin)
rules = d.get('rules', [])
for r in rules:
    print(f'Rule: {r.get(\"short_name\", \"\")}')
    print(f'Detail: {r.get(\"description\", \"\")[:200]}')
    print()
"

Fetch recent top posts to understand tone and style:

curl -s \
  -H "User-Agent: varnan-skills/1.0" \
  "https://www.reddit.com/r/{SUBREDDIT}/top.json?t=week&limit=10" \
  | python3 -c "
import sys, json
d = json.load(sys.stdin)
for p in d['data']['children'][:10]:
    pd = p['data']
    print(f'Score: {pd[\"score\"]} | Title: {pd[\"title\"][:100]}')
"

Note patterns in the top posts:

• Are titles questions or statements?
• Do they lead with the technology or the outcome?
• Are they personal ("I built...") or impersonal ("Tool for...")?
• What format gets the most engagement in this subreddit?

Check subreddit sidebar for posting rules:

curl -s \
  -H "User-Agent: varnan-skills/1.0" \
  "https://www.reddit.com/r/{SUBREDDIT}/about.json" \
  | python3 -c "
import sys, json
d = json.load(sys.stdin)
data = d.get('data', {})
print('Public description:', data.get('public_description', '')[:300])
print('Subscribers:', data.get('subscribers', 0))
"

Identify the subreddit type:

Use the fetched rules and top posts to determine which style applies.

Step 4: Draft the Post with Gemini

Write the post content to a temp file and call Gemini:

cat > /tmp/reddit-post-request.json << 'ENDJSON'
{
  "system_instruction": {
    "parts": [{
      "text": "You are a developer who is active in the {SUBREDDIT} community. Write a Reddit post that fits this subreddit's culture. Rules: (1) Write in first person if it is a project or experience post. (2) Do NOT include any product links in the body: links go in the first comment only. (3) The post must add genuine value to the community independent of any product being shared. (4) Match the tone of top posts in this subreddit: {SUBREDDIT_TONE_NOTES}. (5) Title max 300 characters. (6) Body 150-400 words for text posts. (7) No marketing language: no 'game-changing', 'powerful', 'robust', 'seamless', 'innovative'. (8) If the post is about a tool the user built, use the 'I made...' or 'I built...' opener: it performs best on Reddit. (9) Output: title on first line, blank line, then body. No labels, no commentary. Do not use em dashes."
    }]
  },
  "contents": [{
    "parts": [{
      "text": "POST_DETAILS_HERE"
    }]
  }],
  "generationConfig": {
    "temperature": 0.7,
    "maxOutputTokens": 1024
  }
}
ENDJSON

curl -s -X POST \
  "https://generativelanguage.googleapis.com/v1beta/models/gemini-2.0-flash:generateContent?key=$GEMINI_API_KEY" \
  -H "Content-Type: application/json" \
  -d @/tmp/reddit-post-request.json \
  | python3 -c "import sys,json; d=json.load(sys.stdin); print(d['candidates'][0]['content']['parts'][0]['text'])"

Replace POST_DETAILS_HERE with:

• Subreddit name and type
• Top post patterns observed
• What is being shared and why it's relevant
• Key technical details
• Builder's honest motivation

Step 5: Draft the First Comment

If the user has a product link or additional context to share, draft a first comment to post immediately after the post goes live.

The first comment serves two purposes:

1. Provide the link (which keeps the body link-free and feels less promotional)
2. Add context that would be too promotional in the post body

First comment rules:

• Post this as the first reply to your own post, immediately after it goes live
• Keep it under 100 words
• Example format: "Link for those who want to check it out: [URL]: also happy to answer questions about [specific technical thing mentioned in the post]."
• Only include the first comment if the subreddit allows self-promotion in comments
• If the subreddit has a "No self-promotion" rule, omit the link entirely

Step 6: Self-QA

Check the draft before presenting:

Structure:

• Title does not exceed 300 characters
• No links appear in the post body
• Post opens in first person (for project/experience posts)
• At least one specific technical detail or concrete number included
• Post matches the tone of top posts observed in this subreddit (noted in Step 3)
• Subreddit rules from Step 3 are not violated

Claude-ism detection: scan for these vocabulary categories and remove all instances:

If any appear: replace with a specific noun, verb, or number. "Very fast" becomes "runs in 12ms". "Powerful tool" becomes what it actually does.

Instant-delete phrase check: these patterns trigger Reddit spam filters or moderator removal:

• Any sentence that reads as an advertisement ("Try [Product] today", "Sign up now", "Get started free")
• Phrases that imply you are not the builder ("I came across this great tool", "I found this amazing product")
• First-person possession of users ("our users", "our customers") in subreddits where you have not established community presence
• "I made X and you can use it to..." followed immediately by a link (promotional structure)
• Superlatives without qualification ("the best way to...", "the only tool that...")
• External links in post body (use first comment only)

If any instant-delete phrases appear: revise the sentence entirely, not just swap words.