Debugging AWS Bedrock AgentCore with Postman (and Why I Built This Repo)

2 min readDec 15, 2025

Working with AWS Bedrock AgentCore is powerful — but debugging it can be frustrating.

Between SigV4 signing, runtime session headers, opaque invocation errors, and stateful conversations, even simple testing often turns into trial-and-error with CLI tools or half-baked scripts.

That’s why I built this repository:

👉 https://github.com/dmascia/aws-bedrock-agentcore-postman

This repo provides a production-ready Postman collection designed specifically for AWS Bedrock AgentCore runtime invocations, with a focus on repeatability, debuggability, and correctness.

The Problem

When working with AgentCore, I kept running into the same issues:

Session IDs were inconsistent or accidentally coupled to user identifiers
Runtime headers were easy to forget or misconfigure
SigV4 signing made quick iteration painful
Debugging streaming or prompt behavior required custom tooling every time

Most examples focused on making a single request work, not on supporting real workflows like:

Replaying prompts
Maintaining runtime sessions across requests
Debugging agent state transitions
Testing fallback behavior

What This Repo Solves

The aws-bedrock-agentcore-postman repo solves those problems by providing:

✅ Dynamic Runtime Session Management

Automatically generates a 33-character random session ID
No patient ID, PID, or user data baked into the session
Session ID persists across requests via Postman environment state
Correct headers are injected on every request: runtimeSessionId, X-Amzn-Bedrock-AgentCore-Runtime-Session-Id

✅ AWS SigV4 Auth (Correctly Configured)

Uses Postman’s built-in AWS Signature Version 4
Service: bedrock-agentcore
Region-aware and environment-driven
No custom signing scripts needed

✅ Single, Focused Request: “Send Message”

One clean request that does one thing well
Easy to reason about
Easy to duplicate or extend for other agent actions
Ideal for debugging prompt changes or agent behavior

✅ Production-Friendly Structure

No hard-coded identifiers
Environment variables for credentials and runtime ARN
Clean prerequest scripts with no side effects
Designed to match real backend usage patterns

Why Postman (Still) Matters Here

For agent systems, Postman is underrated.

It gives you:

Visibility into headers and payloads
Easy replay of requests
Rapid iteration without redeploying code
A shared artifact you can hand to backend, infra, or ML teams

When debugging an LLM agent, that feedback loop matters.

Who This Is For

This repo is especially useful if you’re:

Building on AWS Bedrock AgentCore
Debugging agent conversations or state
Testing runtime session behavior
Supporting healthcare, enterprise, or regulated workflows
Tired of reimplementing the same test harness over and over

Repo Link

🔗 GitHub: https://github.com/dmascia/aws-bedrock-agentcore-postman

If you’re working with AgentCore and want a cleaner, more deterministic way to test and debug your runtime calls, this should save you time.