Extract Agent Trajectories with atifact

Convert agent session recordings (HAR files, Claude Code JSONL logs, Copilot CLI JSONL logs) into structured ATIF v1.6 trajectory JSON using the atifact CLI.

Prerequisites

Verify the CLI is available:

command -v atifact

If not installed, install globally:

npm install -g atifact

Supported input formats

Format is auto-detected from file contents (not extension). Use --format / -f to force a specific format when auto-detection fails.

Usage

Basic conversion

The --output / -o option takes a prefix, not a filename. Output files are derived from the prefix:

• Main trajectory: .trajectory.json
• Subagent trajectories: .trajectory..json

Default prefix is the input file path:

atifact session.har
# Writes: session.har.trajectory.json

Specify output prefix

atifact session.har -o out
# Writes: out.trajectory.json
# If subagents exist: out.trajectory.<name>.json

Force input format

Use when auto-detection picks the wrong format for .jsonl files:

atifact session.jsonl -f claude-code-jsonl
atifact session.jsonl -f copilot-cli-jsonl

Pipe JSON to stdout

Use --json with --quiet to suppress diagnostics and get clean JSON on stdout. Output is a JSON array of all trajectories (main first, then subagents). No files are written.

atifact session.har --json --quiet

Combine with other tools:

atifact session.har --json --quiet | jq '.[0].steps | length'

CLI options

Exit codes

Workflow

1. Identify the input file and its format (HAR or JSONL).
2. For .jsonl files, determine the source (Claude Code or Copilot CLI) to use the correct --format if auto-detection fails.
3. Run atifact with the input file. Use -o to set the output prefix (e.g., atifact /path/to/session.har -o /path/to/session). The main trajectory is written to .trajectory.json.
4. Report the output file path(s) and key metrics (total steps, total cost) from the generated trajectory.

Notes

• HAR files may contain multiple API formats (OpenAI + Anthropic); all are parsed.
• Multi-turn HAR conversations are deduplicated (each request carries full history).
• Utility calls (e.g., gpt-4o-mini title generation) are excluded from the trajectory.
• Tool results from request N are attached as observations to the agent step from request N-1.
• Copilot CLI logs with subagent task tool calls produce separate trajectory files per subagent. The main trajectory references them via subagent_trajectory_ref with trajectory_path pointing to the sibling file.
• All timestamps are preserved from source data as-is (ISO 8601).