I’ve noticed a pattern in my coding life. It starts innocently enough. I sit down to write a simple Python script, maybe something to tidy up my Obsidian vault or a quick CLI tool to query an API. “Keep it simple,” I tell myself. “Just input, processing, output.”

But then, the inevitable thought creeps in: It would be cool if the model could decide which file to read based on the user’s question.

Two hours later, I’m not writing a script anymore. I’m writing a while loop. I’m defining a tools array. I’m parsing JSON outputs and handing them back to the model. I’m building memory context windows.

I’m building an agent. Again.

(For those keeping track: my working definition of an “agent” is simple: a model running in a loop with access to tools. I explored this in depth in my Agentic Shift series, but that’s the core of it.)

As I sit here writing this in January of 2026, I realize that almost every AI project I worked on last year ultimately became an agent. It feels like a law of nature: Every AI project, given enough time, converges on becoming an agent. In this post, I want to share some of what I’ve learned, and the cases where you might skip the intermediate steps and jump straight to building an agent.

The Gravitational Pull of Autonomy

This isn’t just feature creep. It’s a fundamental shift in how we interact with software. We are moving past the era of “smart typewriters” and into the era of “digital interns.”

Take Gemini Scribe, my plugin for Obsidian. When I started, it was a glorified chat window. You typed a prompt, it gave you text. Simple. But as I used it, the friction became obvious. If I wanted Scribe to use another note as context for a task, I had to take a specific action, usually creating a link to that note from the one I was working on, to make sure it was considered. I was managing the model’s context manually.

I was the “glue” code. I was the context manager.

The moment I gave Scribe access to the read_file tool, the dynamic changed. Suddenly, I wasn’t micromanaging context; I was giving instructions. “Read the last three meeting notes and draft a summary.” That’s not a chat interaction; that’s a delegation. And to support delegation, the software had to become an agent, capable of planning, executing, and iterating.

From Scripts to Sudoers

The Gemini CLI followed a similar arc. There were many of us on the team experimenting with Gemini on the command line. I was working on iterative refinement, where the model would ask clarifying questions to create deeper artifacts. Others were building the first agentic loops, giving the model the ability to run shell commands.

Once we saw how much the model could do with even basic tools, we were hooked. Suddenly, it wasn’t just talking about code; it was writing and executing it. It could run tests, see the failure, edit the file, and run the tests again. It was eye-opening how much we could get done as a small team.

But with great power comes great anxiety. As I explored in my Agentic Shift post on building guardrails and later in my post about the Policy Engine, I found myself staring at a blinking cursor, terrified that my helpful assistant might accidentally rm -rf my project.

This is the hallmark of the agentic shift: you stop worrying about syntax errors and start worrying about judgment errors. We had to build a “sudoers” file for our AI, a permission system that distinguishes between “read-only exploration” and “destructive action.” You don’t build policy engines for scripts; you build them for agents.

The Classifier That Wanted to Be an Agent

Last year, I learned to recognize a specific code smell: the AI classifier.

In my Podcast RAG project, I wanted users to search across both podcast descriptions and episode transcripts. Different databases, different queries. So I did what felt natural: I built a small classifier using Gemini Flash Lite. It would analyze the user’s question and decide: “Is this a description search or a transcript search?” Then it would call the appropriate function.

It worked. But something nagged at me. I had written a classifier to make a decision that a model is already good at making. Worse, the classifier was brittle. What if the user wanted both? What if their intent was ambiguous? I was encoding my assumptions about user behavior into branching logic, and those assumptions were going to be wrong eventually.

The fix was almost embarrassingly simple. I deleted the classifier and gave the agent two tools: search_descriptions and search_episodes. Now, when a user asks a question, the agent decides which tool (or tools) to use. It can search descriptions first, realize it needs more detail, and then dive into transcripts. It can do both in parallel. It makes the call in context, not based on my pre-programmed heuristics. (You can try it yourself at podcasts.hutchison.org.)

I saw the same pattern in Gemini Scribe. Early versions had elaborate logic for context harvesting, code that tried to predict which notes the user would need based on their current document and conversation history. I was building a decision tree for context, and it was getting unwieldy.

When I moved Scribe to a proper agentic architecture, most of that logic evaporated. The agent didn’t need me to pre-fetch context; it could use a read_file tool to grab what it needed, when it needed it. The complex anticipation logic was replaced by simple, reactive tool calls. The application got simpler and more capable at the same time.

Here’s the heuristic I’ve landed on: If you’re writing if/else logic to decide what the AI should do, you might be building a classifier that wants to be an agent. Deconstruct those branches into tools, give the agent really good descriptions of what those tools can do, and then let the model choose its own adventure.

You might be thinking: “What about routing queries to different models? Surely a classifier makes sense there.” I’m not so sure anymore. Even model routing starts to look like an orchestration problem, and a lightweight orchestrator with tools for accessing different models gives you the same flexibility without the brittleness. The question isn’t whether an agent can make the decision better than your code. It’s whether the agent, with access to the actual data in the moment, can make a decision at least as good as what you’re trying to predict when you’re writing the code. The agent has context you don’t have at development time.

The “Human-on-the-Loop”

We are transitioning from Human-in-the-Loop (where we manually approve every step) to Human-on-the-Loop (where we set the goals and guardrails, but let the system drive).

This shift is driven by a simple desire: we want partners, not just tools. As I wrote back in April about waiting for a true AI coding partner, a tool requires your constant attention. A hammer does nothing unless you swing it. But an agent? An agent can work while you sleep.

This freedom comes with a new responsibility: clarity. If your agent is going to work overnight, you need to make sure it’s working on something productive. You need to be precise about the goal, explicit about the boundaries, and thoughtful about what happens when things go wrong. Without the right guardrails, an agent can get stuck waiting for your input, and you’ll lose that time. Or worse, it can get sidetracked and spend hours on something that wasn’t what you intended.

The goal isn’t to remove the human entirely. It’s to move us from the execution layer to the supervision layer. We set the destination and the boundaries; the agent figures out the route. But we have to set those boundaries well.

Embracing the Complexity (Or Lack Thereof)

Here’s the counterintuitive thing: building an agent isn’t always harder than building a script. Yes, you have to think about loops, tool definitions, and context window management. But as my classifier example showed, an agentic architecture can actually delete complexity. All that brittle branching logic, all those edge cases I was trying to anticipate: gone. Replaced by a model that can reason about what it needs in the moment.

The real complexity isn’t in the code; it’s in the trust. You have to get comfortable with a system that makes decisions you didn’t explicitly program. That’s a different kind of engineering challenge, less about syntax, more about guardrails and judgment.

But the payoff is a system that grows with you. A script does exactly what you wrote it to do, forever. An agent does what you ask it to do, and sometimes finds better ways to do it than you’d considered.

So, if you find yourself staring at your “simple script” and wondering if you should give it a tools definition… just give in. You’re building an agent. It’s inevitable. You might as well enjoy the company.