claude-sessions-mcp

Instructions

Implementation Reference

• src/lib/shared/session-core.ts:402-437 (handler)

  Core handler function that deletes a specific message from a session file by UUID (or messageId for snapshots), repairs the parent-child UUID chain by reparenting direct children to the deleted message's parent, and rewrites the session JSONL file.

  export const deleteMessage = (projectName: string, sessionId: string, messageUuid: string) =>
    Effect.gen(function* () {
      const filePath = path.join(getSessionsDir(), projectName, `${sessionId}.jsonl`)
      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 Record<string, unknown>)
  
      // Find by uuid or messageId (for file-history-snapshot type)
      const targetIndex = messages.findIndex(
        (m) => m.uuid === messageUuid || m.messageId === messageUuid
      )
      if (targetIndex === -1) {
        return { success: false, error: 'Message not found' }
      }
  
      // Get the deleted message's uuid and parentUuid
      const deletedMsg = messages[targetIndex]
      const deletedUuid = deletedMsg?.uuid ?? deletedMsg?.messageId
      const parentUuid = deletedMsg?.parentUuid
  
      // Find all messages that reference the deleted message as their parent
      // and update them to point to the deleted message's parent
      for (const msg of messages) {
        if (msg.parentUuid === deletedUuid) {
          msg.parentUuid = parentUuid
        }
      }
  
      // Remove the message
      messages.splice(targetIndex, 1)
  
      const newContent = messages.map((m) => JSON.stringify(m)).join('\n') + '\n'
      yield* Effect.tryPromise(() => fs.writeFile(filePath, newContent, 'utf-8'))
  
      return { success: true }
    })

• src/mcp/index.ts:73-89 (registration)

  MCP tool registration for 'delete_message', including Zod input schema and thin async handler that delegates to session.deleteMessage and formats the response.

  server.tool(
    'delete_message',
    'Delete a message from a session and repair the parentUuid chain',
    {
      project_name: z.string().describe('Project folder name'),
      session_id: z.string().describe('Session ID'),
      message_uuid: z.string().describe('UUID of the message to delete'),
    },
    async ({ project_name, session_id, message_uuid }) => {
      const result = await Effect.runPromise(
        session.deleteMessage(project_name, session_id, message_uuid)
      )
      return {
        content: [{ type: 'text', text: JSON.stringify(result, null, 2) }],
      }
    }
  )

• src/mcp/index.ts:76-80 (schema)

  Zod schema defining inputs for the delete_message tool: project_name, session_id, and message_uuid as strings.

  {
    project_name: z.string().describe('Project folder name'),
    session_id: z.string().describe('Session ID'),
    message_uuid: z.string().describe('UUID of the message to delete'),
  },