> ## Documentation Index > Fetch the complete documentation index at: https://docs.vern.so/llms.txt > Use this file to discover all available pages before exploring further. # Get the session log > The settled record of a migration: what was planned, which files went in, who approved what, how many rows were written, and whether existing rows were replaced. Intended to be fetched once and stored, so you can explain a migration to your own customer later. It does **not** include the conversation transcript — that is `/thread` — and it does not include individual row values. Available once nothing is in flight, including for migrations that failed: a run can write rows and then fail, which is exactly when this matters. While a run is active the endpoint returns `409`. Pass `?format=md` for the same record as a readable Markdown report. A migration can be imported again later, so the log always covers every run to date — a re-fetch is a superset of an earlier one. Use `generated_at` to tell snapshots apart. ## OpenAPI ````yaml /api-reference/openapi.json get /migrations/{migration_id}/log openapi: 3.1.0 info: title: Vern Migration API version: 1.0.0 description: >- Run Vern as a headless migration engine. Create a migration, upload a customer's files, run the managed agent to generate a preview, then execute and export clean data. See the Migration API guides for concepts and walkthroughs. servers: - url: https://app.vern.so/api/v1 security: - apiKey: [] tags: - name: Catalog description: Discover the sources and templates you set up in the Vern UI. - name: Migrations description: Create a migration workspace and upload a customer's files. - name: Runs description: 'Drive the managed agent: generate, refine, execute, answer, and observe.' - name: Export description: Download a migration's validated data as CSV. - name: Log description: The settled record of what a migration did. - name: Knowledge description: Durable context the agent reads before every run. - name: Exports description: Download imported data. - name: Extractions description: >- Turn an unstructured file into structured data, without running a migration. paths: /migrations/{migration_id}/log: parameters: - $ref: '#/components/parameters/MigrationId' get: tags: - Log summary: Get the session log description: | The settled record of a migration: what was planned, which files went in, who approved what, how many rows were written, and whether existing rows were replaced. Intended to be fetched once and stored, so you can explain a migration to your own customer later. It does **not** include the conversation transcript — that is `/thread` — and it does not include individual row values. Available once nothing is in flight, including for migrations that failed: a run can write rows and then fail, which is exactly when this matters. While a run is active the endpoint returns `409`. Pass `?format=md` for the same record as a readable Markdown report. A migration can be imported again later, so the log always covers every run to date — a re-fetch is a superset of an earlier one. Use `generated_at` to tell snapshots apart. operationId: getSessionLog parameters: - name: format in: query schema: type: string enum: - json - md - markdown default: json responses: '200': description: The session log. content: application/json: schema: $ref: '#/components/schemas/SessionLog' text/markdown: schema: type: string '401': $ref: '#/components/responses/Unauthorized' '404': $ref: '#/components/responses/MigrationNotFound' '409': description: >- The migration is still in progress. Body carries the current `status` and `retry_after_seconds`. content: application/json: schema: allOf: - $ref: '#/components/schemas/Error' - type: object properties: status: $ref: '#/components/schemas/MigrationStatus' retry_after_seconds: type: integer example: 30 '429': $ref: '#/components/responses/RateLimited' '500': $ref: '#/components/responses/ServerError' '503': description: The log could not be assembled. Retryable. content: application/json: schema: $ref: '#/components/schemas/Error' components: parameters: MigrationId: name: migration_id in: path required: true description: The migration ID returned by Create a migration. schema: type: string format: uuid example: c0a8012e-4f1b-4d3a-9b2c-7e6f5a4b3c2d schemas: SessionLog: type: object properties: migration_id: type: string generated_at: type: string status: $ref: '#/components/schemas/MigrationStatus' covers: type: object properties: runs: type: integer from: type: string nullable: true to: type: string nullable: true runs: type: array items: $ref: '#/components/schemas/SessionLogRun' Error: type: object properties: error: type: string description: A human-readable error message. required: - error MigrationStatus: type: string enum: - awaiting_files - ready - awaiting_approval - completed description: | - `awaiting_files` — no files uploaded and no source connection - `ready` — inputs present, no plan yet - `awaiting_approval` — a preview is waiting to be executed - `completed` — an import has run successfully SessionLogRun: type: object properties: run_id: type: string kind: type: string description: '`generate`, `update`, `reuse`, `clarify` or `execute`.' status: type: string started_at: type: string nullable: true completed_at: type: string nullable: true started_by: type: string nullable: true description: Null when the run was started through this API. files: type: array items: type: string plan: type: string nullable: true questions: type: array items: type: object answers: type: object outcome: type: object nullable: true properties: ok: type: boolean nullable: true rows_written: type: integer nullable: true per_sheet: type: array items: type: object properties: sheet: type: string nullable: true rows: type: integer nullable: true invalid_rows: type: integer nullable: true error: type: string nullable: true replaced_existing_data: type: boolean description: >- True when this run emptied its destination sheets before writing — it replaced the previous import rather than adding to it. audit: type: array description: Who did what, in order. items: type: object properties: at: type: string event: type: string enum: - started - resumed - templates_adjusted - plan_approved - unknown actor: type: string nullable: true mode: type: string answers_excerpt: type: string changes: type: array items: type: object plan: type: string responses: Unauthorized: description: API key missing, malformed, or revoked. content: application/json: schema: $ref: '#/components/schemas/Error' MigrationNotFound: description: >- No migration with this id in your organisation. Returned rather than `403` so the existence of another organisation's migration is not disclosed. content: application/json: schema: $ref: '#/components/schemas/Error' RateLimited: description: Rate limit hit — back off and retry. content: application/json: schema: $ref: '#/components/schemas/Error' example: error: Too many requests ServerError: description: Unexpected server error. content: application/json: schema: $ref: '#/components/schemas/Error' securitySchemes: apiKey: type: apiKey in: header name: x-api-key description: Your Vern API key. Create one at Settings → API keys. ````