Obsidian Memory MCP

Instructions

Implementation Reference

• storage/MarkdownStorageManager.ts:202-242 (handler)

  Core handler function that implements the add_observations tool logic: loads entity markdown, filters duplicates, appends new observations, reloads relations, and saves the updated file.
  async addObservations(observations: { entityName: string; contents: string[] }[]): Promise<{ entityName: string; addedObservations: string[] }[]> { const results: { entityName: string; addedObservations: string[] }[] = []; for (const obs of observations) { const entityPath = getEntityPath(obs.entityName); try { // Load current entity const entity = await this.loadEntity(entityPath); if (!entity) { throw new Error(`Entity ${obs.entityName} not found`); } // Filter out duplicate observations const newObservations = obs.contents.filter( content => !entity.observations.includes(content) ); if (newObservations.length > 0) { // Update entity entity.observations.push(...newObservations); // Get current relations for this entity const graph = await this.loadGraph(); const entityRelations = graph.relations.filter(r => r.from === entity.name); // Save updated entity await this.saveEntity(entity, entityRelations); results.push({ entityName: obs.entityName, addedObservations: newObservations }); } } catch (error) { throw new Error(`Failed to add observations to ${obs.entityName}: ${error}`); } } return results; }
• index.ts:77-101 (schema)

  Input schema definition and tool metadata (name, description) for the add_observations tool, used in MCP tool listing.
  { name: "add_observations", description: "Add new observations to existing entities in the knowledge graph", inputSchema: { type: "object", properties: { observations: { type: "array", items: { type: "object", properties: { entityName: { type: "string", description: "The name of the entity to add the observations to" }, contents: { type: "array", items: { type: "string" }, description: "An array of observation contents to add" }, }, required: ["entityName", "contents"], }, }, }, required: ["observations"], }, },
• index.ts:215-216 (handler)

  MCP server dispatch handler case for add_observations, invoking the storage manager's implementation and formatting response.
  case "add_observations": return { content: [{ type: "text", text: JSON.stringify(await storageManager.addObservations(args.observations as { entityName: string; contents: string[] }[]), null, 2) }] };
• index.ts:26-201 (registration)

  Registration of all tools including add_observations via the ListToolsRequestHandler, exposing the tool to MCP clients.
  server.setRequestHandler(ListToolsRequestSchema, async () => { return { tools: [ { name: "create_entities", description: "Create multiple new entities in the knowledge graph", inputSchema: { type: "object", properties: { entities: { type: "array", items: { type: "object", properties: { name: { type: "string", description: "The name of the entity" }, entityType: { type: "string", description: "The type of the entity" }, observations: { type: "array", items: { type: "string" }, description: "An array of observation contents associated with the entity" }, }, required: ["name", "entityType", "observations"], }, }, }, required: ["entities"], }, }, { name: "create_relations", description: "Create multiple new relations between entities in the knowledge graph. Relations should be in active voice", inputSchema: { type: "object", properties: { relations: { type: "array", items: { type: "object", properties: { from: { type: "string", description: "The name of the entity where the relation starts" }, to: { type: "string", description: "The name of the entity where the relation ends" }, relationType: { type: "string", description: "The type of the relation" }, }, required: ["from", "to", "relationType"], }, }, }, required: ["relations"], }, }, { name: "add_observations", description: "Add new observations to existing entities in the knowledge graph", inputSchema: { type: "object", properties: { observations: { type: "array", items: { type: "object", properties: { entityName: { type: "string", description: "The name of the entity to add the observations to" }, contents: { type: "array", items: { type: "string" }, description: "An array of observation contents to add" }, }, required: ["entityName", "contents"], }, }, }, required: ["observations"], }, }, { name: "delete_entities", description: "Delete multiple entities and their associated relations from the knowledge graph", inputSchema: { type: "object", properties: { entityNames: { type: "array", items: { type: "string" }, description: "An array of entity names to delete" }, }, required: ["entityNames"], }, }, { name: "delete_observations", description: "Delete specific observations from entities in the knowledge graph", inputSchema: { type: "object", properties: { deletions: { type: "array", items: { type: "object", properties: { entityName: { type: "string", description: "The name of the entity containing the observations" }, observations: { type: "array", items: { type: "string" }, description: "An array of observations to delete" }, }, required: ["entityName", "observations"], }, }, }, required: ["deletions"], }, }, { name: "delete_relations", description: "Delete multiple relations from the knowledge graph", inputSchema: { type: "object", properties: { relations: { type: "array", items: { type: "object", properties: { from: { type: "string", description: "The name of the entity where the relation starts" }, to: { type: "string", description: "The name of the entity where the relation ends" }, relationType: { type: "string", description: "The type of the relation" }, }, required: ["from", "to", "relationType"], }, description: "An array of relations to delete" }, }, required: ["relations"], }, }, { name: "read_graph", description: "Read the entire knowledge graph", inputSchema: { type: "object", properties: {}, }, }, { name: "search_nodes", description: "Search for nodes in the knowledge graph based on a query", inputSchema: { type: "object", properties: { query: { type: "string", description: "The search query to match against entity names, types, and observation content" }, }, required: ["query"], }, }, { name: "open_nodes", description: "Open specific nodes in the knowledge graph by their names", inputSchema: { type: "object", properties: { names: { type: "array", items: { type: "string" }, description: "An array of entity names to retrieve", }, }, required: ["names"], }, }, ], }; });