causetrace 0.1.2

Causal traceability SDK for AI agent runtimes — observe, replay, understand agent behavior

causetrace

中文 • CI • PyPI

causetrace captures tool calls from coding agents (Claude Code, OpenCode, Aider, Continue.dev, Codex CLI, GitHub Copilot) and links them into causal trees and DAGs — not flat timelines. Every event records why it happened, enabling replay, root-cause analysis, and behavior explanation.

Data sources: Claude Code (hooks), OpenCode / Continue.dev / Codex CLI / GitHub Copilot (log tailing), Aider (process wrapper)
Storage: ~/.causetrace/data/<session_id>.jsonl — append-only JSONL, zero external dependencies

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Showcase

The same session viewed four ways — flat vs. causal.

Timeline (flat)

$ causetrace timeline ses_10d2f16e
[03:13:37] Read(file_path=src/main.py)
[03:13:37] Grep(pattern=FIXME)
[03:13:37] Read(file_path=src/utils.py)
[03:13:37] Read(file_path=src/utils.py)
[03:13:38] Edit(file_path=src/utils.py)
[03:13:38] Bash(command=python -m pytest tests/ -x)
[03:13:38] Grep(pattern=counter)
[03:13:38] Edit(file_path=docs/api.md)
[03:13:38] Bash(command=python -m pytest tests/)

Chronological order, but no insight into why each event happened.

Causal Tree

$ causetrace tree ses_10d2f16e
[03:13:37] Read(file_path=src/main.py)
    └─ [03:13:37] Grep(pattern=FIXME)
      └─ [03:13:37] Read(file_path=src/utils.py)
[03:13:37] Read(file_path=src/utils.py)  [caused by: need_context]
    └─ [03:13:38] Edit(file_path=src/utils.py)
      └─ [03:13:38] Bash(command=python -m pytest tests/ -x)
[03:13:38] Grep(pattern=counter)
    └─ [03:13:38] Edit(file_path=docs/api.md)
      └─ [03:13:38] Bash(command=python -m pytest tests/)

Parent→child chains reveal the causal structure: each tool call is a direct response to its parent.

Why (causal chain trace)

$ causetrace why ses_10d2f16e <event_id>
[03:13:38] Grep(pattern=counter) ──→
[03:13:38] Edit(file_path=docs/api.md) ──→
[03:13:38] Bash(command=python -m pytest tests/) ◀── TARGET

Trace why a specific event happened — follow the causal chain backward from any event to its root.

Multi-parent DAG

$ causetrace graph ses_3e23bcc8
[02:42:40] Bash(command=python -m pytest tests/)  ← Edit(file_path=docs/api.md)
[02:42:41] Read(file_path=src/main.py)
[02:42:41] Grep(pattern=FIXME)  ← Read(file_path=src/main.py)
[02:42:41] Read(file_path=src/utils.py)  ← Grep(pattern=FIXME)
[02:42:41] Read(file_path=src/utils.py)
[02:42:41] Edit(file_path=src/utils.py)  ← Read(file_path=src/utils.py)
[02:42:41] Bash(command=python -m pytest tests/ -x)  ← Edit(file_path=src/utils.py)
[02:42:42] Grep(pattern=counter)
[02:42:42] Edit(file_path=docs/api.md)  ← Grep(pattern=counter)

Fan-in DAGs visualize convergent causation — one tool consuming multiple prior results. Support for multi-parent causal links via comma-separated parent_event_id.

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Supported Agents

Agent	Method	How it works
Claude Code	Hook bridge	PreToolUse / PostToolUse hooks via ~/.claude/settings.json
OpenCode	Log tailing	Parses ~/.local/share/opencode/log/*.log for tool.registry entries
Aider	Process wrapper	Runs aider as subprocess, parses stdout for tool calls
Continue.dev	Log tailing	Parses ~/.continue/logs/core.log for JSON tool call entries
Codex CLI	Log tailing	Parses ~/.codex/sessions/.../rollout-*.jsonl for actions/observations
GitHub Copilot	Log tailing	Parses ~/.config/Code/logs/ extension host logs for Copilot tool calls

# Claude Code — automatic via hooks
causetrace tale <session_id>

# Log-based agents — scan and save
causetrace opencode --save
causetrace continue --save
causetrace codex --save
causetrace copilot --save

# Aider — run with tracing
causetrace aider -- --model gpt-4 --yes "fix the bug"

Usage notes:

• Claude Code — most precise, captures full causality via Pre/Post hooks
• Aider — causetrace aider --save -- [aider args] wraps the CLI; best-effort parsing from output
• Continue.dev, Codex CLI, Copilot — post-hoc log scanning; causality inferred from temporal proximity via infer_relations()
• All log-based agents infer causality heuristically — timestamps between events determine parent→child chains

---

Quick Start

pip install causetrace

# Run a demo with sample data
causetrace timeline ses_10d2f16e
causetrace tree    ses_10d2f16e
causetrace replay  ses_10d2f16e --summary
causetrace why     ses_10d2f16e <event_id>

Hook up Claude Code

Add to ~/.claude/settings.json to start recording every Claude Code session automatically.

{
  "hooks": {
    "PreToolUse": [{ "matcher": "*", "hooks": [{
      "type": "command",
      "command": "python3 /path/to/causetrace/hooks/claude_code.py",
      "timeout": 5
    }]}],
    "PostToolUse": [{ "matcher": "*", "hooks": [{
      "type": "command",
      "command": "python3 /path/to/causetrace/hooks/claude_code.py",
      "timeout": 5
    }]}]
  }
}

Scan OpenCode logs

causetrace opencode --save

Parses OpenCode log files, infers causal relations from temporal proximity, and saves as a causetrace session.

---

Data Model

Every event is a ToolEvent. The four causal fields (parent_event_id, session_id, event_type, caused_by) distinguish causetrace from flat logging systems.

Field	Description
event_id	UUID
parent_event_id	Causal parent (comma-separated for fan-in)
session_id	Owning session
tool_name	e.g. Bash, Read, Write
tool_input	Serialized input arguments
tool_output	Serialized output
timestamp	ISO 8601
duration_ms	Execution time
event_type	tool_call / reasoning / context_update / user_input
caused_by	user / reasoning / event_id / semantic tag

---

CLI Reference

Command	Description
causetrace timeline <id>	Flat chronological view
causetrace tree <id>	Causal parent→child tree
causetrace graph <id>	Multi-parent DAG (fan-in)
causetrace sessions	List recorded sessions
causetrace export <id>	Export as JSON
causetrace replay <id>	Replay with provenance
causetrace why <id> <eid>	Trace causal chain from event
causetrace opencode [--save]	Scan OpenCode logs
causetrace aider [--save] -- [args]	Run aider with tracing
causetrace continue [--save]	Scan Continue.dev logs
causetrace codex [--save]	Scan OpenAI Codex CLI logs
causetrace copilot [--save]	Scan GitHub Copilot agent logs

---

Architecture

┌──────────────┐  ┌──────────────┐  ┌──────────────┐  ┌──────────────┐  ┌──────────────┐  ┌──────────────┐
│ Claude Code  │  │   OpenCode   │  │    Aider     │  │ Continue.dev │  │  Codex CLI   │  │   Copilot    │
│  (hooks)     │  │ (log tail)   │  │ (subprocess) │  │ (log tail)   │  │ (log tail)   │  │ (log tail)   │
└──────┬───────┘  └──────┬───────┘  └──────┬───────┘  └──────┬───────┘  └──────┬───────┘  └──────┬───────┘
       │                 │                 │                 │                 │                 │
       ▼                 ▼                 ▼                 ▼                 ▼                 ▼
┌────────────────────────────────────────────────────────────────────────────────────────────────────┐
│                                    TraceRecorder                                                    │
│                             (causal linking, storage)                                               │
└────────────────────────────────────────────────────────────────────────────────────────────────────┘
                                                │
                                                ▼
┌────────────────────────────────────────────────────────────────────────────────────────────────────┐
│                                           JSONStore                                                │
│                                (append-only JSONL, no DB)                                          │
└────────────────────────────────────────────────────────────────────────────────────────────────────┘
                                                │
                                                ▼
┌────────────────────────────────────────────────────────────────────────────────────────────────────┐
│                              Tree / DAG Builders                                                    │
│                              Renderers / ReplayEngine                                               │
└────────────────────────────────────────────────────────────────────────────────────────────────────┘

Module	Responsibility
causetrace/core.py	Data model, TraceRecorder, JSONStore, tree/DAG builders, renderers, ReplayEngine
causetrace/causality.py	Temporal causal inference for unstructured logs
causetrace/cli.py	argparse CLI dispatching to 12 subcommands
causetrace/hooks/	Agent-specific bridges and tailers
causetrace/hooks/claude_code.py	Claude Code hook bridge
causetrace/hooks/opencode_tailer.py	OpenCode log tailer
causetrace/hooks/aider_bridge.py	Aider subprocess wrapper
causetrace/hooks/continue_tailer.py	Continue.dev log tailer
causetrace/hooks/codex_tailer.py	Codex CLI log tailer
causetrace/hooks/copilot_tailer.py	GitHub Copilot log tailer

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Development

git clone https://github.com/milkoor/causetrace.git
cd causetrace
pip install -e .
python -m pytest tests/ -v

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License

MIT