No glamorous start — just a late-night thought. A week of building DeepSeek Phone Harness, from zero to release.
In bed that night, I realized I could have the agent on my computer run a task early. Get up and walk to the study? Too much trouble. Give up? Unsatisfying.
In that moment it hit me: the agent's value is doing work for me, yet I'm chained to the computer.
Next morning I opened the editor and decided to solve it myself.
The core idea was simple: the phone sends HTTP, an agent process translates it into DSH RPC, and translates responses back.
That evening the first version worked: send a sentence from the phone, the agent on the computer executes, the result returns to the phone. Ugly, but it moved.
On day three, tasks started "randomly hanging." I dug until late night and found: the agent asks the user questions, questions don't go through the approval channel, and I wasn't listening to the question channel. Tasks waited forever on a question nobody answered.
When it was fixed, my commit message said three words: "no more hangs."
Results weren't enough — I wanted the phone to see what the agent does, step by step.
So tool cards were born: one card per tool call, with icon, status, the file path it touched, and expandable full arguments and results. The agent's reasoning also folds into a collapsible block.
That night I sat watching the agent work on my phone for a long time. "Watching it think and move" versus "waiting for a result" are two completely different experiences.
Added the terminal (remote commands), file browsing, task history (one-tap re-run), and session management (rename/delete/search).
Wrote the README, wrote the promo posts, pushed to GitHub. There was no ceremony — just git push
and a long exhale.
~4000 lines, zero npm dependencies, one Node process + one HTML file.
It runs stably: dispatch tasks on the commute, tweak config before bed, tap approvals mid-meeting. The phone became the agent's remote — "wherever you are, your agent is too" is no longer just a slogan.
Open source (MIT), three-minute setup:
git clone https://github.com/2903077918-lgtm/DeepSeek-phone-harness
cd DeepSeek-phone-harness && cp config.example.json config.json
node agent.mjs --mode=both
Install Tailscale on the phone, access over 4G/5G.
If you were to build an open-source project "for yourself," what pain point would you solve first? Comment below — the next viral project might start here.