Reddit MCP Server

Instructions

Implementation Reference

• src/tools/post-tools.ts:131-210 (handler)

  The primary handler function for the 'create_post' MCP tool. It processes input parameters, authenticates with the Reddit client, calls the underlying client.createPost method, formats the response using formatPostInfo, and returns structured content or throws MCP errors with specific messages.
  export async function createPost(params: { subreddit: string; title: string; content: string; is_self?: boolean; }) { const { subreddit, title, content, is_self = true } = params; const client = getRedditClient(); if (!client) { throw new McpError( ErrorCode.InternalError, "Reddit client not initialized" ); } try { console.log( `[Tool] Creating ${is_self ? "text" : "link"} post in r/${subreddit}: "${title}"` ); const startTime = Date.now(); const post = await client.createPost(subreddit, title, content, is_self); const endTime = Date.now(); console.log(`[Tool] Post creation took ${endTime - startTime}ms`); const formattedPost = formatPostInfo(post); return { content: [ { type: "text", text: ` # ✅ Post créé avec succès ! ## 📝 Détails du post - **Titre**: ${formattedPost.title} - **Subreddit**: r/${formattedPost.subreddit} - **Type**: ${formattedPost.type} - **ID**: ${post.id} - **Auteur**: u/${formattedPost.author} ## 🔗 Liens - **Lien complet**: ${formattedPost.links.fullPost} - **Permalink**: https://reddit.com${post.permalink} ## ⏰ Statut Votre post a été **publié avec succès** sur r/${formattedPost.subreddit} ! ${is_self ? `**Contenu**: ${content.substring(0, 200)}${content.length > 200 ? '...' : ''}` : `**URL**: ${content}` } `, }, ], }; } catch (error: any) { console.error(`[Error] Error creating post: ${error}`); // Provide more specific error messages let errorMessage = `Échec de la création du post: ${error.message}`; if (error.message.includes('timeout')) { errorMessage = `⏰ Timeout lors de la création du post. Le post a peut-être été créé malgré tout - vérifiez votre profil Reddit.`; } else if (error.message.includes('authentication')) { errorMessage = `🔐 Problème d'authentification. Vérifiez vos credentials Reddit dans le fichier .env`; } else if (error.message.includes('rate limit')) { errorMessage = `⏱️ Limite de fréquence atteinte. Attendez quelques minutes avant de réessayer.`; } else if (error.message.includes('submission')) { errorMessage = `📝 Erreur de soumission. Vérifiez que le subreddit existe et que vous avez les permissions.`; } throw new McpError( ErrorCode.InternalError, errorMessage ); } }
• src/index.ts:180-207 (schema)

  The input schema definition for the 'create_post' tool, specifying parameters (subreddit, title, content, is_self), types, descriptions, defaults, and required fields.
  name: "create_post", description: "Create a new post in a subreddit", inputSchema: { type: "object", properties: { subreddit: { type: "string", description: "Name of the subreddit to post in", }, title: { type: "string", description: "Title of the post", }, content: { type: "string", description: "Content of the post (text for self posts, URL for link posts)", }, is_self: { type: "boolean", description: "Whether this is a self (text) post (true) or link post (false)", default: true, }, }, required: ["subreddit", "title", "content"], }, },
• src/index.ts:454-462 (registration)

  The registration and dispatch logic in the CallToolRequestHandler switch statement, which maps the 'create_post' tool name to the tools.createPost function call.
  case "create_post": return await tools.createPost( toolParams as { subreddit: string; title: string; content: string; is_self?: boolean; } );
• src/client/reddit-client.ts:270-352 (helper)

  The core helper method in RedditClient that handles the actual Reddit API submission (/api/submit), including authentication check, parameter formatting, API call, response handling, post retrieval, and comprehensive error management.
  async createPost( subreddit: string, title: string, content: string, isSelf: boolean = true ): Promise<RedditPost> { await this.authenticate(); if (!this.username || !this.password) { throw new Error("User authentication required for posting"); } try { console.log(`[Post] Creating post in r/${subreddit}: "${title}"`); const kind = isSelf ? "self" : "link"; const params = new URLSearchParams(); params.append("sr", subreddit); params.append("kind", kind); params.append("title", title); params.append(isSelf ? "text" : "url", content); const response = await this.api.post("/api/submit", params, { headers: { "Content-Type": "application/x-www-form-urlencoded", }, timeout: 30000, // 30 seconds timeout }); console.log(`[Post] Reddit API response:`, response.data); if (response.data.success) { const postId = response.data.data.id; const postName = response.data.data.name; console.log(`[Post] Post created successfully! ID: ${postId}, Name: ${postName}`); try { // Try to get the newly created post const newPost = await this.getPost(postId); console.log(`[Post] Successfully retrieved created post`); return newPost; } catch (getError) { console.log(`[Post] Could not retrieve post details, but post was created successfully`); // Return a basic post object if we can't retrieve the full details return { id: postId, title: title, author: this.username!, subreddit: subreddit, selftext: isSelf ? content : "", url: isSelf ? "" : content, score: 1, upvoteRatio: 1.0, numComments: 0, createdUtc: Math.floor(Date.now() / 1000), over18: false, spoiler: false, edited: false, isSelf: isSelf, linkFlairText: "", permalink: `/r/${subreddit}/comments/${postId}/`, }; } } else { console.error(`[Post] Reddit API returned success=false:`, response.data); const errors = response.data.errors || []; const errorMsg = errors.length > 0 ? errors.join(", ") : "Unknown error"; throw new Error(`Failed to create post: ${errorMsg}`); } } catch (error: any) { console.error(`[Error] Failed to create post in r/${subreddit}:`, error); if (error.response) { console.error(`[Error] Reddit API error response:`, error.response.data); throw new Error(`Failed to create post: ${error.response.data?.message || error.message}`); } else if (error.code === 'ECONNABORTED') { console.error(`[Error] Request timeout when creating post`); throw new Error(`Post creation timed out - check Reddit manually to see if it was created`); } else { throw new Error(`Failed to create post in r/${subreddit}: ${error.message}`); } } }