Quick picks: what are you doing?
- Adding it to Claude: follow connect Claude to CommunityMentions.
- Writing your own client: use the calls on this page.
- Matching a product to subreddits: call find_subreddits.
- Checking one subreddit: call get_subreddit.
- Looking through the data by hand: use the subreddit list.
The server at a glance
Every value below comes from calling the endpoint on November 6, 2026, or from its entry in the official MCP registry.
| Field | Value |
|---|---|
| Endpoint | https://communitymentions.com/api/mcp |
| Transport | Streamable HTTP, POST only, JSON responses |
| Sessions | None; each request stands alone |
| Authentication | None |
| Server name and version | communitymentions 1.0.0 |
| Protocol version we negotiated | 2025-06-18 |
| Registry name | com.communitymentions/communitymentions, published October 15, 2026 |
| Engines in the data | OpenAI models, Perplexity, Gemini |
| Data date | November 1, 2026 |
The two tools
| Tool | Input | Limits | Returns |
|---|---|---|---|
| find_subreddits | description: what the product or niche is, in a few words | 2 to 120 characters | Up to 10 subreddits, closest match first, with category, members, AI citations, citing answers, threads cited, verified comments placed and a page link |
| get_subreddit | subreddit: a name such as SaaS or r/marketing | 2 to 60 characters | Those fields plus rank, first and last cited dates, citations by engine, answers by question type and most-cited threads |
Call initialize
Both headers matter. Without the content type the server answers 415, and without an Accept header naming both types it answers 406. The line after the command is the start of the real response on November 6, 2026.
curl -s -X POST https://communitymentions.com/api/mcp \
-H 'Content-Type: application/json' \
-H 'Accept: application/json, text/event-stream' \
-d '{"jsonrpc":"2.0","id":1,"method":"initialize","params":{"protocolVersion":"2025-06-18","capabilities":{},"clientInfo":{"name":"my-client","version":"1.0"}}}'
{"result":{"protocolVersion":"2025-06-18","capabilities":{"tools":{"listChanged":true}},"serverInfo":{"name":"communitymentions","version":"1.0.0"},"instructions":"CommunityMentions tracks which Reddit communities AI answers cite. (shortened here)"},"jsonrpc":"2.0","id":1}Call find_subreddits
The body below went to the same URL with the same headers. The text that follows is the first part of the real response on November 6, 2026.
{"jsonrpc":"2.0","id":3,"method":"tools/call","params":{"name":"find_subreddits","arguments":{"description":"project management software for small agencies"}}}
Subreddits that fit "project management software for small agencies", closest match first (the median subreddit AI answers cite 50+ times has 97 citations, across 105 such subreddits):
1. r/smallbusiness (SaaS and startups): 210 AI citations, 2,471,103 members. https://communitymentions.com/subreddits/smallbusiness?utm_source=mcp
2. r/smallbusinessowner (SaaS and startups): under 50 AI citations, 43,536 members. https://communitymentions.com/subreddits/smallbusinessowner?utm_source=mcp
3. r/growmybusiness (SaaS and startups): under 50 AI citations, 104,323 members. https://communitymentions.com/subreddits/growmybusiness?utm_source=mcpCall get_subreddit
The same response also comes as structured JSON in structuredContent, with the fields listed above.
{"jsonrpc":"2.0","id":4,"method":"tools/call","params":{"name":"get_subreddit","arguments":{"subreddit":"SaaS"}}}
r/SaaS (SaaS and startups): 302 AI citations, 702,778 members. https://communitymentions.com/subreddits/saas?utm_source=mcp
Cited in 254 AI answers from 2026-02-27 to 2026-10-30; rank #10 of 146 subreddits cited 50+ times. By engine: OpenAI models 40, Perplexity 208, Gemini 54.
Most-cited threads:
1. 3 ways to promote your product on reddit without… (25 citations) https://www.reddit.com/r/SaaS/comments/1lq13x4/3_ways_to_promote_your_product_on_reddit_without/
2. I launched my product what now (17 citations) https://www.reddit.com/r/SaaS/comments/1osioys/i_launched_my_product_what_now/
3. How do you actually do reddit marketing without… (16 citations) https://www.reddit.com/r/SaaS/comments/1qn56t8/how_do_you_actually_do_reddit_marketing_without/
4. Whats the best reddit marketing tool (13 citations) https://www.reddit.com/r/SaaS/comments/1pcalml/whats_the_best_reddit_marketing_tool/
5. Alternatives to clearbit or zoominfo for accurate… (11 citations) https://www.reddit.com/r/SaaS/comments/1k7h208/alternatives_to_clearbit_or_zoominfo_for_accurate/Errors you can expect
| What you sent | What came back on November 6, 2026 |
|---|---|
| GET to the endpoint | 405, Method not allowed |
| POST with no JSON content type | 415, Unsupported Media Type |
| POST with no Accept header naming both JSON and event-stream | 406, Not Acceptable |
| find_subreddits with query in place of description | isError true, -32602 input validation error |
| get_subreddit with name in place of subreddit | isError true, -32602 input validation error |
Limits and what the data leaves out
- 146 subreddits were cited 50 or more times across all answers. The tools return 211 subreddits, and 105 of those carry a published citation count, because we don't publish counts under 50. A subreddit with 50+ verified comments placed can be in the list with no citation count. get_subreddit ranks against all 146, and 41 of those are not among the 211; we have not itemised why.
- Health, legal-help and adult communities are left out.
- Claude's answers are not in the data.
- Nothing is written. Both tools are marked read-only and idempotent.
- Each call logs the tool name, its success and its time. What you asked is not logged.
Sources
- The live endpoint, called with curl on November 6, 2026.
- Official MCP registry entry, read November 6, 2026.
- Data: citations from 78,023 AI answers, January 9 to October 30, 2026, in data dated November 1, 2026. See the subreddit data pages.