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The reddit MCP adapter connects to the Reddit OAuth API. Fetch post details and comment threads, create self or link posts, comment, edit, and delete content — useful for community monitoring, moderated publishing, and social automation with human approval.

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Prerequisites

  • A Reddit account and a Reddit app (script or web app type)
  • OAuth client ID, client secret, and refresh token for the posting account
  • Moderator or posting permissions on target subreddits
  • A descriptive User-Agent string (Reddit requires unique app identification)
  • project_contributor access in AgentRuntime

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Connect in AgentRuntime

1

Create a Reddit application

At reddit.com/prefs/apps, create an app and note the client ID (under the app name) and client secret.
2

Obtain a refresh token

Complete the OAuth authorization code flow for the Reddit account that will post or comment. Store the refresh token securely.
3

Create a connection

Go to Connections and click New custom connection to create a connection with ClientID, ClientSecret, RefreshToken, and UserAgent (e.g. agentruntime:workflow:v1.0 (by /u/yourname)).
4

Add reddit MCP instance

Go to MCP, click Add instance for reddit, wire your connection on Instance config, set the profile active, and save.
5

Test read access

Run mcp_call → retrieve_reddit_post on a public post ID before enabling write tools.
See Authentication for binding connections to MCP instances.
Always use human_task approval before create_reddit_post or create_reddit_comment in production subreddits. Respect subreddit rules and Reddit API rate limits.

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What you can build

  • Community monitoring — Scheduled fetch_post_comments → LLM sentiment summary → alert on negative trends.
  • Approved publishing — Draft post in workflow → human_task → create_reddit_post as self or link post.
  • Support triage — get_reddit_post_details on mentions → create ClickUp or GitLab ticket from thread context.
  • Thread cleanup — edit_reddit_post_or_comment or delete_reddit_post_or_comment after moderation review.

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Tools

ToolDescription
retrieve_reddit_postGet a post by ID or fullname (t3_...)
get_reddit_post_detailsDetailed post metadata by ID or fullname
fetch_post_commentsComments for a post in a subreddit
create_reddit_postCreate a self (text) or link post in a subreddit
create_reddit_commentReply to a post or comment (thing_id)
edit_reddit_post_or_commentEdit post or comment text
delete_reddit_post_or_commentDelete a post or comment
reddit_custom_api_callRaw authenticated Reddit OAuth API request

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Example

Post a link after human approval: 
{
  "id": "reddit-post",
  "type": "mcp_call",
  "name": "Publish Reddit post",
  "tool_name": "create_reddit_post",
  "tool_args": {
    "subreddit": "{{input.subreddit}}",
    "title": "{{steps.human-approve.result.title}}",
    "kind": "link",
    "url": "{{input.article_url}}"
  },
  "depends_on": ["human-approve"],
  "timeout_s": 30
}

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Configuration

KeyRequiredDescription
ClientIDYesReddit application client ID
ClientSecretYesReddit application client secret
RefreshTokenYesOAuth refresh token for the authenticated user
UserAgentNoUnique User-Agent string (strongly recommended)
RequestTimeoutSecondNoHTTP timeout in seconds
OAuthBaseURLNoReddit OAuth API base URL
TokenURLNoOAuth token endpoint

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Troubleshooting

IssueFix
401 / token errorsRefresh token revoked; re-run OAuth flow
403 on postAccount lacks karma, subreddit restrictions, or mod approval required
Rate limitingReddit enforces per-account limits; add delays between automated posts
Wrong parent on commentUse fullname format: t3_ for posts, t1_ for comments