Alexander Richey

Software Engineer @AWSCloud.

[kosti @kosti_v]

And with that... 𝗔𝗴𝗲𝗻𝘁𝗖𝗼𝗿𝗲 𝗵𝗮𝗿𝗻𝗲𝘀𝘀 𝗶𝘀 𝗻𝗼𝘄 𝗚𝗔! 🎉

Every AI agent needs the same scaffolding underneath: tools to interact with, an environment to work in, a system to manage context, memory to personalize, identity to control access, and observability to understand and course correct. Wrapped in a loop that calls the model, picks a tool, and recovers from failures. This is the agent harness, and until we launched it in preview, every team using AgentCore built it from scratch.

Today, the managed agent harness in AgentCore is generally available. You declare your agent and run it in two API calls. You point to the model, tools, skills, and instructions as configuration, and AgentCore stitches together everything around it to make the agent production-ready. What you get out of the box:

1️⃣ 𝗔𝗻𝘆 𝗺𝗼𝗱𝗲𝗹, 𝘀𝘄𝗶𝘁𝗰𝗵 𝗺𝗶𝗱-𝘀𝗲𝘀𝘀𝗶𝗼𝗻. Bedrock, OpenAI, Gemini, or any LiteLLM-supported provider. Switch providers mid-session without losing context. Plan on one model, code on another, summarize on a third.

2️⃣ 𝗧𝗼𝗼𝗹𝘀, 𝗱𝗲𝗰𝗹𝗮𝗿𝗮𝘁𝗶𝘃𝗲𝗹𝘆. MCP servers, AgentCore Gateway, built-in Browser and Code Interpreter, or your own inline functions. One config line per tool, with no boilerplate to write.

3️⃣ 𝗕𝘂𝗶𝗹𝘁-𝗶𝗻 𝗺𝗲𝗺𝗼𝗿𝘆, 𝘀𝘁𝗮𝘁𝗲𝗳𝘂𝗹 𝗯𝘆 𝗱𝗲𝗳𝗮𝘂𝗹𝘁. Memory is on out of the box, persisting users and conversations across sessions. Each session also runs in its own secure, isolated microVM with a filesystem and shell.

4️⃣ 𝗦𝗸𝗶𝗹𝗹𝘀 𝗼𝗻 𝗱𝗲𝗺𝗮𝗻𝗱. Compose your agent with bundles of markdown and scripts that give it domain knowledge. Pull from git, S3, your own path, or flip on the full AWS-curated catalog with a single 𝚊𝚠𝚜𝚂𝚔𝚒𝚕𝚕𝚜 toggle. The harness loads and executes them only when the task calls for it.

5️⃣ 𝗥𝘂𝗻 𝗶𝗻 𝘁𝗵𝗲 𝗲𝗻𝘃𝗶𝗿𝗼𝗻𝗺𝗲𝗻𝘁 𝘆𝗼𝘂 𝗻𝗲𝗲𝗱. Use the default image, or bring your own container with your source, runtimes, and dependencies. Persist files with managed session storage, or mount EFS or S3 Files for state that outlives a session.

6️⃣ 𝗢𝗯𝘀𝗲𝗿𝘃𝗲, 𝗲𝘃𝗮𝗹𝘂𝗮𝘁𝗲, 𝗼𝗽𝘁𝗶𝗺𝗶𝘇𝗲. Unified observability gives you one view across every primitive the agent touched. Score real traffic with built-in evaluators, get prompt and tool recommendations, and A/B test them on live traffic before you roll out.

7️⃣ 𝗩𝗲𝗿𝘀𝗶𝗼𝗻, 𝗿𝗼𝗹𝗹 𝗯𝗮𝗰𝗸, 𝗮𝗻𝗱 𝗲𝘅𝗽𝗼𝗿𝘁. Every update is an immutable version, so rollback is pointing an endpoint at an earlier one. And when config stops being enough, export to Strands-based code and keep running on the same compute, same microVM, same observability. No re-architecture, no platform tax.

Trying a new model or tool is a config change, not a code rewrite. Managing context, remembering across users, adding a skill, tuning a prompt: again config, not infrastructure. The whole loop (build, connect, optimize, ship) collapses from weeks into minutes.

Read more in our launch blog: https://t.co/seJp4flUOh

[Alexander Richey @AlexanderRichey]

Thinking through the consequences of my belief that there isn't an afterlife... https://t.co/CaI7MQO41R

[Alexander Richey @AlexanderRichey]

@GoVeMcl I could probably find some time to do that one of these days 🙂

[Alexander Richey @AlexanderRichey]

Enjoyed this article about music and the current cultural mood. I wonder if this pattern holds true globally?
https://t.co/VEJRoXaio8

[Alexander Richey @AlexanderRichey]

This article reminds me of why I voted for Hillary back in 2016. A weak candidate in retrospect, she genuinely cares about America and its social fabric, unlike her opponents who prosper from its disintegration.
https://t.co/ucFFyy32bm

[Alexander Richey @AlexanderRichey]

Interesting article by @jon_rauch about the need for structure and the limits of self-organization in politics. "The world of unstructured interpersonal exchange looks a lot like Twitter," he writes, "an epistemic version of Hobbes's state of nature."
https://t.co/g0sPm3px2L

[Alexander Richey @AlexanderRichey]

@hernansartorio Wildly impressive! Congrats @hernansartorio!

[Alexander Richey @AlexanderRichey]

I wrote this article as I started my road trip across the United States, already one year ago.

https://t.co/xyrJg9JCdn

[Alexander Richey @AlexanderRichey]

Thanks @aquaVitae_AK and @vaskal08 for one of the best uses AI that I've seen so far—to remove sensationalism from the news. https://t.co/LPUbLGXvvi

[Alexander Richey @AlexanderRichey]

@kohidave You also make your app less portable, and now to actually develop on it, you have to deploy to a dev environment on AWS—you can't just run it locally anymore in a nice little HTTP server that does it all.

5/5

[Alexander Richey @AlexanderRichey]

@kohidave You can use AWS solutions to solve these problems, but then it becomes harder to tell what's going on, since you end up moving business logic into configuration, e.g., you move routing into an API Gateway config and now your actual app code doesn't do that anymore.

4/n

[Alexander Richey @AlexanderRichey]

@kohidave The other option is to write code for Lambda from the start, but then you have to solve a bunch of problems on your own—routing, auth, etc.

3/n

[Alexander Richey @AlexanderRichey]

@kohidave To deploy these kind of apps to Lambda, you need to, first, know to use API Gateway to make the Lambda function callable via HTTP, and, second, you need to write some code to adapt your existing code to the Lambda handler signature, which is kind of a pain.

2/n

[Alexander Richey @AlexanderRichey]

@kohidave I have a take @kohidave! Many of the major application frameworks that many companies use are based on HTTP—Rails, Django, Express, Spring, etc. And they all have a nice dev experience where you run a little server locally. And great docs and tutorials made by the community.

1/n

[Alexander Richey @AlexanderRichey]

Thinking a bit about intellectual humility:
https://t.co/v5vd3N5E39

[Alexander Richey @AlexanderRichey]

You can now deploy images from private ECR repositories to Lightsail Containers 🍰
https://t.co/1r2CVMLb0n

[Alexander Richey @AlexanderRichey]

@nickfrenchnyc Ah, being out here in Seattle, I don't have my finger on the pulse of NYC politics. But I liked the idea of a philosopher like you in public office. 😀

[Alexander Richey @AlexanderRichey]

@tdinh_me I used my own project to save a bunch of these: https://t.co/sL6PyUtBxB

[Alexander Richey @AlexanderRichey]

@DrTexx @jeremy_soller @andrewbadr was working on a similar project called @MixilyEvents, but it looks like its focus has changed to online events. I'd be interested to know if you find a solution 🙂