get_session_files

Retrieve all files modified during a Claude Code session to track changes and review project history.

Instructions

Get list of all files changed in a session (from file-history-snapshot and tool_use)

Input Schema

TableJSON Schema

Name	Required	Description	Default
`project_name`	Yes	Project folder name
`session_id`	Yes	Session ID

Implementation Reference

src/mcp/index.ts:138-151 (registration)

Registers the 'get_session_files' MCP tool, including input schema (project_name, session_id) and thin handler that delegates to session.getSessionFiles

server.tool(
  'get_session_files',
  'Get list of all files changed in a session (from file-history-snapshot and tool_use)',
  {
    project_name: z.string().describe('Project folder name'),
    session_id: z.string().describe('Session ID'),
  },
  async ({ project_name, session_id }) => {
    const result = await Effect.runPromise(session.getSessionFiles(project_name, session_id))
    return {
      content: [{ type: 'text', text: JSON.stringify(result, null, 2) }],
    }
  }
)

src/lib/session.ts:260-325 (handler)

Core implementation of getSessionFiles: parses session messages, extracts unique file changes from 'file-history-snapshot' and 'tool_use' (Write/Edit) blocks

export const getSessionFiles = (projectName: string, sessionId: string) =>
  Effect.gen(function* () {
    const messages = yield* readSession(projectName, sessionId)
    const fileChanges: FileChange[] = []
    const seenFiles = new Set<string>()

    for (const msg of messages) {
      // Check for file-history-snapshot type
      if (msg.type === 'file-history-snapshot') {
        const snapshot = msg as unknown as {
          type: string
          messageId?: string
          snapshot?: {
            trackedFileBackups?: Record<string, unknown>
            timestamp?: string
          }
        }

        const backups = snapshot.snapshot?.trackedFileBackups
        if (backups && typeof backups === 'object') {
          for (const filePath of Object.keys(backups)) {
            if (!seenFiles.has(filePath)) {
              seenFiles.add(filePath)
              fileChanges.push({
                path: filePath,
                action: 'modified',
                timestamp: snapshot.snapshot?.timestamp,
                messageUuid: snapshot.messageId ?? msg.uuid,
              })
            }
          }
        }
      }

      // Also check tool_use for Write/Edit operations
      if (msg.type === 'assistant' && msg.message) {
        const assistantMsg = msg.message as {
          content?: Array<{ type: string; name?: string; input?: { file_path?: string } }>
        }
        const content = assistantMsg.content
        if (Array.isArray(content)) {
          for (const block of content) {
            if (block.type === 'tool_use' && (block.name === 'Write' || block.name === 'Edit')) {
              const filePath = block.input?.file_path
              if (filePath && !seenFiles.has(filePath)) {
                seenFiles.add(filePath)
                fileChanges.push({
                  path: filePath,
                  action: block.name === 'Write' ? 'created' : 'modified',
                  timestamp: msg.timestamp,
                  messageUuid: msg.uuid,
                })
              }
            }
          }
        }
      }
    }

    return {
      sessionId,
      projectName,
      files: fileChanges,
      totalChanges: fileChanges.length,
    } satisfies SessionFilesSummary
  })

src/lib/session.ts:252-257 (schema)

TypeScript interface defining the output structure of getSessionFiles

export interface SessionFilesSummary {
  sessionId: string
  projectName: string
  files: FileChange[]
  totalChanges: number
}

src/lib/session.ts:104-110 (helper)

Helper function readSession loads and parses session messages from .jsonl file, used by getSessionFiles

export const readSession = (projectName: string, sessionId: 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)
    return lines.map((line) => JSON.parse(line) as Message)
  })

src/mcp/index.ts:142-144 (schema)

Zod input schema for the MCP tool parameters

  project_name: z.string().describe('Project folder name'),
  session_id: z.string().describe('Session ID'),
},

claude-sessions-mcp