downloading-batch-export-files

Downloading batch export files

Use this skill when a user wants a one-off downloadable export of PostHog data. The export is started and monitored through MCP, but the final file download uses the existing REST endpoint directly.

Available MCP tools

Do not rely on a generated MCP tool for the /download/ endpoint. That endpoint is a redirecting file download endpoint, so raw HTTP/download handling is the right interface until MCP has explicit redirect support.

Workflow

1. Choose the export shape

Ask a short clarifying question if the user did not specify the required inputs:

• model: one of events, persons, sessions, or hogql
• data_interval_start and data_interval_end: ISO 8601 datetimes. Any supplied bound may not be in the future. When both bounds are supplied, they must be ordered and at most one week apart Required for events, persons, and sessions. For hogql, required only for the placeholders the query references. If only one placeholder is referenced, the other bound may be omitted and the one-week limit does not apply.
• file.format: Parquet or JSONLines; prefer Parquet for compact analytics exports and JSONLines for line-oriented text processing
• file.compression: optional, one of zstd, gzip, brotli, lz4, or snappy. If JSONLines was chosen as format, only gzip and brotli are supported.
• file.max_size_mb: part size in MiB, 1024 by default. A part can go a little over this size. Lower it when the user wants smaller parts, raise it for fewer and bigger ones, or set it to null to write a single file of any size.

For events, include and exclude are optional event-name filters. Use them only when the user asks for specific events or wants to omit specific events.

For hogql, pass the query as hogql_query and leave out include and exclude. You may prompt the user to export a slice of data by including a WHERE clause in the HogQL query, for example limiting results from the events table by bounding timestamp. Always prefer limiting the data exported to the minimum necessary to solve the user's request. Every column in the SELECT clause must be a field or have an alias. This model is in closed beta and is enabled per team.

A hogql query can reference the {data_interval_start} and {data_interval_end} placeholders. The export replaces them with the data_interval_start and data_interval_end values, so one query can export any interval. Supply a bound for every placeholder the query references; a missing bound fails the request. The bounds only replace placeholders and do not filter anything themselves, so a query without placeholders runs unchanged even when bounds are supplied. Prefer placeholders over literal dates when the user wants a time range, or several consecutive ranges from the same query. Compare with >= {data_interval_start} and < {data_interval_end}, so consecutive ranges do not export the same row twice.

2. Start the export

Call posthog:file-download-batch-exports-create with the selected shape. The response contains an id for the export run.

Example request:

{
  "model": "events",
  "file": {
    "format": "JSONLines",
    "compression": "gzip"
  },
  "include": ["$pageview"],
  "data_interval_start": "2026-05-25T00:00:00Z",
  "data_interval_end": "2026-05-26T00:00:00Z"
}

Example request for the hogql model:

{
  "model": "hogql",
  "file": {
    "format": "Parquet"
  },
  "hogql_query": "SELECT event, timestamp, properties.$current_url AS url FROM events WHERE timestamp >= {data_interval_start} AND timestamp < {data_interval_end}",
  "data_interval_start": "2026-05-25T00:00:00Z",
  "data_interval_end": "2026-05-26T00:00:00Z"
}

3. Poll until completion

Call posthog:file-download-batch-exports-retrieve with the returned id.

Status handling:

When Completed, the files array contains file UUIDs. For single-file exports it usually contains one UUID. For split exports, download every UUID unless the user asked for a specific part.

A Completed response also carries records_completed, the number of rows the run exported. Report it to the user, because the count is otherwise only visible by opening every file.

4. Optionally, cancel a running export

If required by the user, a running export can be cancelled by calling posthog:file-download-batch-exports-cancel-create with the returned id.

An export that has already finished or has already failed may not be cancelled.

After cancelling an export, the id may not be used anymore and the export must start again from the beginning. However, you may still use the id to retrieve the export status (which will always be Cancelled).

5. Download files through REST

Use a direct authenticated HTTP request to the existing endpoint:

GET /api/projects/{project_id}/file_download_batch_exports/{run_id}/download/{part}/

part can be either:

• a file UUID from the files array returned by file-download-batch-exports-retrieve
• a zero-based file index, ordered by key

If there is only one file, this also works without part:

GET /api/projects/{project_id}/file_download_batch_exports/{run_id}/download/

Let the HTTP client follow the redirect, or inspect the Location header if you need the temporary signed URL. Use the same PostHog authentication context as other API calls.

6. Save, do not print, file contents

Treat the result as a file download, not a chat response. Parquet is binary and must be written as bytes. JSONLines may still be large; save it to a file rather than pasting the contents unless the user explicitly asks for a tiny sample.

Use a filename that includes the model, run ID, and part identifier when possible, for example:

posthog-events-<run_id>-<part>.jsonl.gz
posthog-persons-<run_id>-<part>.parquet

Important notes

• The maximum export interval is one week. Split longer user requests into separate export runs or ask which week to export.
• The hogql model is in closed beta and is enabled per team. A permission error that says HogQL batch exports are not enabled means the team does not have the beta. Report that instead of retrying with a different query, and tell the user they can contact PostHog support to request access.
• The hogql model runs under stricter resource limits than the other models, because user queries are less predictable. If an export fails on memory, execution time, or bytes read, suggest narrowing the query with a WHERE clause instead of retrying it unchanged.
• The hogql model accepts an optional hogql_modifiers object. Each modifier in it overrides the project HogQL modifier with the same name for this export only, and the project modifiers apply to all others. By default, timestamp columns come out in the project timezone, so pass {"convertToProjectTimezone": false} when the user wants UTC timestamps. Pass the same hogql_modifiers to posthog:file-download-batch-exports-count-rows-create, so that the count matches the export.
• A run can briefly report Running after completion while file records are being created. Poll again instead of failing immediately.
• Download URLs are temporary. If a URL expires, call the REST download endpoint again for a fresh redirect.
• Do not send the signed URL to unrelated services unless the user explicitly asks; it grants temporary access to the exported file.
• If the user wants all parts of a split export, iterate over every UUID in files; do not assume part 0 is enough.
• Large batch exports may take a few minutes or even longer to complete. Suggest to the user that they can speed-up their download by including only certain events or narrowing the date range.