claude-sessions-mcp

Instructions

Implementation Reference

• src/mcp/index.ts:29-34 (handler)

  MCP tool handler for 'list_sessions': invokes session.listSessions(project_name) and returns the result as formatted JSON text content.

  async ({ project_name }) => {
    const result = await Effect.runPromise(session.listSessions(project_name))
    return {
      content: [{ type: 'text', text: JSON.stringify(result, null, 2) }],
    }
  }

• src/mcp/index.ts:26-28 (schema)

  Zod input schema defining the 'project_name' parameter for the list_sessions tool.

  {
    project_name: z.string().describe("Project folder name (e.g., '-Users-young-works-myproject')"),
  },

• src/mcp/index.ts:23-35 (registration)

  Registration of the 'list_sessions' tool on the McpServer instance.

  server.tool(
    'list_sessions',
    'List all sessions in a project',
    {
      project_name: z.string().describe("Project folder name (e.g., '-Users-young-works-myproject')"),
    },
    async ({ project_name }) => {
      const result = await Effect.runPromise(session.listSessions(project_name))
      return {
        content: [{ type: 'text', text: JSON.stringify(result, null, 2) }],
      }
    }
  )

• src/lib/session.ts:57-101 (helper)

  Core implementation of listSessions: reads session files in a project directory, parses messages, extracts metadata (title from first human message, counts, timestamps), returns array of SessionMeta objects.

  export const listSessions = (projectName: string) =>
    Effect.gen(function* () {
      const projectPath = path.join(getSessionsDir(), projectName)
      const files = yield* Effect.tryPromise(() => fs.readdir(projectPath))
      const sessionFiles = files.filter((f) => f.endsWith('.jsonl'))
  
      const sessions = yield* Effect.all(
        sessionFiles.map((file) =>
          Effect.gen(function* () {
            const filePath = path.join(projectPath, file)
            const content = yield* Effect.tryPromise(() => fs.readFile(filePath, 'utf-8'))
            const lines = content.trim().split('\n').filter(Boolean)
            const messages = lines.map((line) => JSON.parse(line) as Message)
  
            const sessionId = file.replace('.jsonl', '')
            const firstMessage = messages[0]
            const lastMessage = messages[messages.length - 1]
  
            // Extract title from first user message
            const title = pipe(
              messages,
              A.findFirst((m) => m.type === 'human'),
              O.map((m) => {
                const msg = m.message as { content?: string } | undefined
                const content = msg?.content ?? ''
                return content.slice(0, 50) + (content.length > 50 ? '...' : '')
              }),
              O.getOrElse(() => 'Untitled')
            )
  
            return {
              id: sessionId,
              projectName,
              title,
              messageCount: messages.length,
              createdAt: firstMessage?.timestamp,
              updatedAt: lastMessage?.timestamp,
            } satisfies SessionMeta
          })
        ),
        { concurrency: 10 }
      )
  
      return sessions
    })