here-i-strand 0.2.10

here-i-strand (HIS) agent module. Provides a custom Strands agent with DynamoDB status tracking, S3 session persistence and a concurrent tool executor with per-tool timeouts

Here I Strand

Library that provides a Strands agent for AWS Bedrock Agent Core with DynamoDB status tracking, S3 session persistence, and a concurrent tool executor with per-tool timeouts (HIS: here-i-strand).

Repository: github.com/tisaarus/here-i-strand

Installation

pip install here-i-strand
# or with uv
uv add here-i-strand

Quick start

You define how to load configuration (environment variables, your own settings module, etc.) and pass the values to HISAgent:

import os
from his import HISAgent

agent = HISAgent(
    bucket_name=os.environ["BUCKET_NAME"],
    status_dynamo_table_name=os.environ["STATUS_DYNAMO_TABLE_NAME"],
    session_id="my-session-id",
    name=os.environ.get("AGENT_NAME", "my-agent"),
    agent_id=os.environ.get("AGENT_ID"),  # Optional: unique identifier for the agent instance
    tools=[...],
)

Configuration

The library does not provide a settings layer. Pass bucket_name, status_dynamo_table_name, session_id, and optionally name, agent_id (and any other HISAgent arguments) from your own config:

• Environment variables
• A .env file loaded by your app (e.g. python-dotenv, pydantic-settings)
• Any other configuration source you use

Project structure (development)

here-i-strand/
├── README.md
├── pyproject.toml
├── .env.example             # Example env vars (for your app)
│
├── his/                      # Main package
│   ├── __init__.py           # HISAgent, TimeoutConcurrentToolExecutor, event_loop_tracker, write_dynamo
│   ├── his.py                # HISAgent, TimeoutConcurrentToolExecutor, event_loop_tracker, write_dynamo
│   └── logging/
│       └── logging.py
│
└── tests/
    ├── conftest.py
    └── test_his.py

Main components

• HISAgent: Strands agent with DynamoDB status tracking and optional S3-backed sessions. You pass status_dynamo_table_name, session_id, and optionally bucket_name, name, and agent_id so the tracker and session persistence use your table and bucket. Includes a default system prompt that enforces DynamoDB status reporting at key milestones. The write_dynamo tool is automatically added to the agent's tools.
• TimeoutConcurrentToolExecutor: Tool executor with a per-invocation timeout (default: 300s); if a tool exceeds the limit, an error is returned and execution continues with the rest.
• event_loop_tracker: Callback that writes event-loop milestones (init_event_loop, result, force_stop) to DynamoDB along with session and agent identifiers.
• write_dynamo: Strands tool for writing custom event records to DynamoDB for agent tracking and observability. Automatically included in HISAgent. Each call creates a new append-only event item identified by a composite key (session_id, event_id).
• DEFAULT_DYNAMODB_REPORTING_PROMPT_TEMPLATE: Template for the default system prompt that instructs the agent to report status updates to DynamoDB at key milestones such as START, TOOLING, MODEL_INVOCATION, PROGRESS, COMPLETION, and ERROR. The template is populated with the actual table_name, session_id, and agent_id values when the agent is created and explicitly instructs the agent to keep this reporting completely invisible to the end user.
• HISBedrockThrottlingLogger: Hook provider that listens for ModelThrottledException events and writes BEDROCK_THROTTLING records to DynamoDB for observability, independent of the system prompt.

Default behavior

When you create an HISAgent, the following happens automatically:

1. System prompt: The DEFAULT_DYNAMODB_REPORTING_PROMPT_TEMPLATE is formatted with your status_dynamo_table_name, session_id, and agent_id and prepended to any custom system prompt you provide. It instructs the agent to report status at key milestones (START, TOOLING, MODEL_INVOCATION, PROGRESS, COMPLETION, ERROR) while keeping this reporting hidden from the user.
2. Tools: The write_dynamo tool is automatically added to your tools list, enabling the agent to write status updates to DynamoDB.
3. Session persistence: If you provide bucket_name, the agent uses S3SessionManager to persist session history. If bucket_name is omitted, no session manager is created.
4. Event tracking: The event_loop_tracker callback records event-loop milestones to DynamoDB.
5. Invocation telemetry: The __call__ method logs AGENT_STATS and RESULT events to DynamoDB and returns the standard AgentResult.

DynamoDB status events and schema

The library expects a DynamoDB table where status and telemetry events are written in an append-only fashion:

• Partition key: session_id (String)
• Sort key: event_id (String, UUID generated per event)

Each item also includes:

• agent_id: Agent instance identifier
• evt_type: Event type (e.g. START, TOOLING, MODEL_INVOCATION, PROGRESS, BEDROCK_THROTTLING, COMPLETION, ERROR, EVENT_LOOP, AGENT_STATS, RESULT)
• evt_message: Human-readable message describing the event or a JSON-encoded payload
• evt_datetime: ISO datetime of when the event was recorded

Typical high-level event types written by the agent are:

• START: Beginning of request processing.
• TOOLING: Before executing any external tool (includes tool name and purpose).
• MODEL_INVOCATION: Before invoking another model or sub-agent.
• PROGRESS: Significant progress or intermediate result checkpoints.
• BEDROCK_THROTTLING: Bedrock throttling errors (rate/concurrency limits), including retry context.
• AGENT_STATS: Aggregated usage metrics for the invocation (tokens, cache usage, user).
• RESULT: Final structured result of the agent run, stored as JSON when possible (falls back to a {"raw": "<text>"} wrapper when parsing fails).
• COMPLETION: Successful end of processing.
• ERROR: Unexpected errors with details for debugging.

Tests

uv sync --all-groups
uv run pytest tests/ -v

Authors

• Lorenzo Pizarro Martin
• Antonio Calavia Robert
• Manuel Sierra Lavado

License

MIT. See LICENSE.