blocklog 0.2.2

Infrastructure for AI Decision-Making — record, replay, verify, and govern AI agent decisions

Blocklog Python SDK

Record, audit, and investigate every decision your AI agents make.

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Why Blocklog?

When AI agents execute actions in production, the context behind their decisions is often lost. Debugging failures, reproducing state, and maintaining compliance becomes nearly impossible without a structured audit trail. Blocklog solves this by capturing exactly what the model knew, what tools it used, and what it ultimately decided—all securely anchored and optionally requiring human approval.

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What Blocklog Does

• Trace AI agents and their execution duration automatically.
• Trace tool calls, capturing inputs and outputs seamlessly.
• Record decisions with detailed metadata, inputs, and outputs.
• Request approvals via non-blocking human-in-the-loop workflows.
• Verify records cryptographically against a blockchain anchor.
• Generate compliance evidence (e.g., SOC2, GDPR).
• Investigate failures with replay using forensic timelines and root-cause analysis.

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Architecture Overview

    AI Agent
       ↓
@blocklog.agent
       ↓
 Tools + Decisions
       ↓
  Event Buffer
       ↓
  Blocklog API
       ↓
Replay / Verification / Compliance

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Installation

Blocklog requires Python 3.10+. Install the SDK from PyPI:

pip install blocklog

For development installation or to install from source:

git clone https://github.com/blockloghq/blocklog-python.git
cd blocklog-python
pip install -e .

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Quickstart

import os
import blocklog

# 1. Initialize the SDK
blocklog.init(api_key=os.environ.get("BLOCKLOG_API_KEY", "blk_demo_key"))

# 2. Record tool calls
@blocklog.tool
def check_price(ticker: str) -> float:
    return 412.50

# 3. Trace your agent
@blocklog.agent(name="simple-trader")
def run_agent():
    price = check_price("TSLA")
    
    # 4. Record the decision
    with blocklog.decision(type="BUY", asset="TSLA") as d:
        d.record_input(price=price)
        d.record_output(order_id="ord_123")
        
    print(f"Decision recorded: {d.id}")

if __name__ == "__main__":
    run_agent()

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What Happens Under The Hood?

When you apply @blocklog.agent, Blocklog starts an internal session context that automatically propagates a trace_id to any subsequent operations. When @blocklog.tool is invoked, it captures the inputs and outputs, linking them to the active trace. Finally, blocklog.decision() bundles the agent's logic into a concrete, auditable event that is asynchronously buffered and flushed to the Blocklog backend without blocking your application.

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Core Concepts

• Decision: A structured record of an AI action, tracking the explicit inputs it considered and the outputs it generated.
• Trace: The end-to-end execution path of an agent, automatically correlating all tool calls and decisions via a shared trace_id.
• Event: A low-level building block representing a single state change (e.g., TOOL_CALL, DECISION_INPUT), securely buffered and dispatched.
• Approval: A human-in-the-loop (HITL) gate that flags high-stakes decisions for manual review.
• Replay: A forensic reconstruction of a trace allowing developers to understand the root cause of an agent's failure or action.

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Common Use Cases

• Trading Agents: Capturing the exact market data (inputs) that led an agent to execute a trade (output).
• AI Copilots: Tracing user interactions and the tools invoked to fetch internal company data.
• Compliance-Sensitive Workflows: Automatically generating SOC2 or GDPR reports for AI behavior.
• Customer Support Agents: Recording decisions to escalate to human agents vs. resolving automatically.
• Human-in-the-Loop Systems: Pausing execution of high-value actions (e.g., refunds > $500) until a human reviewer approves.

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Integrations

Blocklog seamlessly auto-instruments popular AI frameworks:

• LangChain: Trace chains, LLMs, and tools automatically via client.instrument_langchain().
• LangGraph: Hook into graph states via client.instrument_langgraph().
• OpenAI Agents: Track official SDK executions via client.instrument_openai_agents().

Read more in the Integrations Guide.

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Documentation

Topic	Guide
Getting Started	Installation • Quickstart • Core Concepts
Instrumentation	Tracing • Decisions • Decorators
Frameworks	Integrations
Operations	Async Usage • Production • Performance
Reference	API Reference • Error Handling • Troubleshooting
Misc	Examples • Changelog

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Examples

We provide several runnable scripts in the examples/ directory to help you understand Blocklog in practice:

• 01_quickstart.py: The bare minimum needed to trace an agent, run a tool, and record a decision.
• 02_stock_trading_agent.py: A simulated trading agent demonstrating tool tagging, human-in-the-loop approvals, and cryptographic verification.
• 03_multi_agent_workflow.py: A complex pipeline showing context passing across Analyst, Risk, and Executor agents, ending in a compliance report.

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Production Features

• Async Support: Native asyncio compatibility utilizing contextvars for seamless trace propagation across await boundaries.
• Event Buffering: High-volume telemetry is safely batched in-memory and flushed asynchronously.
• Retry Handling: Built-in exponential backoff for transient network issues.
• Signing: Optional Ed25519 payload signing for tamper-evident, cryptographically verifiable logs.
• Middleware Hooks: Add custom logic to redact PII or inject metadata before payloads leave your server.

Read our Production Best Practices for more details.

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Contributing

We welcome contributions to the Blocklog Python SDK! Please read through our open issues or submit a Pull Request. Ensure you have installed the SDK in editable mode (pip install -e .) before running tests.

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Configuration

Blocklog can be configured via environment variables:

Variable	Description	Default
BLOCKLOG_API_KEY	Your Blocklog API key	""
BLOCKLOG_BASE_URL	API base URL	http://127.0.0.1:8000/api/v1
BLOCKLOG_SDK_SIGNING_KEY	Optional seed key for hash signing	""
BLOCKLOG_TIMEOUT	Request timeout in seconds	10
BLOCKLOG_MAX_RETRIES	Number of retry attempts	3
BLOCKLOG_BATCH_SIZE	Event batch size	100
BLOCKLOG_FLUSH_INTERVAL	Batch flush interval in seconds	2

Troubleshooting

Installation Issues

If you encounter installation errors:

# Upgrade pip first
pip install --upgrade pip

# Install with verbose output
pip install blocklog -v

Import Errors

If you get import errors after installation:

# Verify installation
pip show blocklog

# Reinstall if needed
pip install --force-reinstall blocklog

Connection Issues

If the SDK cannot connect to the Blocklog API:

1. Verify your API key is correct
2. Check that BLOCKLOG_BASE_URL points to the correct endpoint
3. Ensure network connectivity to the API server
4. Check firewall settings

Links

• Homepage: https://blockloghq.com
• Documentation: https://docs.blockloghq.com
• Repository: https://github.com/blockloghq/blocklog-python
• Issues: https://github.com/blockloghq/blocklog-python/issues
• PyPI: https://pypi.org/project/blocklog/

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License

MIT License. See the LICENSE file for details.