The agent's next stop is your pocket: why "mobile" may be one of the agent's best forms

We moved agents from the terminal to the browser. Now it's time to move them into your pocket. This isn't "mobile adaptation" — it's a shift in interaction paradigm.

DeepSeek Harness just went open source, and the community is excited — models, tools, agent loops, all pluggable. But amid the noise I noticed something:

Everyone's discussing what agents can do. Almost nobody discusses where you use them.

Let's talk about the second one — and I'll give you my own answer.

Agent usage is moving from "sit down" to "anytime"

First generation: open a terminal, sit down, watch.

Second generation (Web GUI): open a browser, sit down, watch.

Essentially it's still "you must be seated at the computer." But an agent's whole value is that it does the work for you — and yet you have to babysit it. Is that reasonable?

On the commute, I want it to start running first
Before bed, I want to assign tomorrow's tasks
Mid-meeting, it needs an approval — I want to tap once and let it continue

All these share one trait: you're not at the computer, but the agent is working. Who's the remote? The phone is the only answer.

Mobile isn't a "shrunk webpage" — it's a new paradigm

I used to think mobile = shrunk web. After actually building it, I found mobile's interaction logic is fundamentally different:

1. From "multiple windows" to "a single timeline"

The web has panels side by side: conversation, tool output, approval dialogs. Mobile naturally has one vertical timeline — user message, agent reasoning, tool cards, approval cards, question cards, all linear. The agent's work becomes a replayable pipeline, which is clearer, not less.

2. From "clicking around" to "making decisions"

On desktop you click everywhere. On mobile, thumb reach is limited, which forces interactions into "look once → decide": allow this tool call or not? How to answer this question? — judgment calls, not browsing sessions.

3. From "accompanying" to "async"

On desktop you sit with the agent. On mobile you dispatch → leave → come back for results. That pushes the agent side to do state management properly (task queues, result retention, failure notifications) — which is exactly where agent products are heading.

My answer: an open-source project that puts the agent in your pocket

Based on the above, I built DeepSeek Phone Harness:

Control DeepSeek Harness on your computer from a mobile browser (4G/5G, Tailscale direct)
Streaming output, tool cards (path/status/detail), approvals, question answers, model switching, terminal, files
Zero npm dependencies, ~4000 lines, single-file frontend
MIT open source, clone and run

It's no revolutionary invention — just a plain answer: "when the agent works for you, you shouldn't have to be there."