Downloads

Track downloads and verify completion inside the verification loop (e.g., download_completed("report.csv") / downloadCompleted("report.csv")).

This page covers:

• What download tracking captures (best-effort)
• How to verify completion deterministically
• Where download evidence shows up (trace/artifacts)

Table of Contents

1. What gets tracked
2. Verification predicate
3. Examples
4. Debugging

What gets tracked

Download capture is best-effort and depends on backend support, but the runtime tries to record:

• completed download filename (when available)
• completion timestamps and basic metadata (when available)

The goal is not “perfect file system introspection,” but a reliable signal you can use in assertions.

Verification predicate

Use the download predicate in a required assertion (or as a done gate).

from predicate import download_completed

# Gate step success on a specific file appearing as completed
runtime.assert(download_completed("report.csv"), "download_ok", required=True)

Examples

Verify a download after a click

from predicate import click, download_completed

runtime.begin_step("Download report")
snap = await runtime.snapshot(limit=80)

# (Find the download button your preferred way, then click it)
click(browser, element_id)

# Re-snapshot and verify the download finished
await runtime.snapshot()
runtime.assert(download_completed("report.csv"), "report_downloaded", required=True)

Debugging

If a download assertion fails:

• Inspect your trace step-by-step:
  • Tracing
  • Debugging Agent Failures
• Confirm the click actually triggered a download (some sites open a new tab, trigger a blob URL, or require an extra confirmation UI).

Related topics

• Agent Runtime — assertions and done gates
• Tracing — where download evidence shows up