Fix a bug from your phone: chat, diff, preview and tests

TL;DR: You can use Thumbdesk to ask a coding agent for a fix, inspect the resulting files and git diff, try the app and run tests from your phone. The work runs in a project on your own computer. This walkthrough uses a checkout-tax example to show the full sequence, including what to check before committing. We build Thumbdesk; have the host paired and your chosen agent CLI installed and authenticated before starting.

Fix a bug from your phone with a clear task#

Use a project you know and a bug you can describe precisely. In this example, the checkout stores money in cents, but a tax calculation can return a fraction of a cent. The intended change is to round tax once on the subtotal and add a regression test.

Before starting, check the branch and existing working-tree changes. That gives you a baseline for distinguishing the agent's edits from work already in progress. The host must be awake, online and running its agent.

Ask the agent for a focused change#

Open the host's Chats view, start a conversation and select the project folder. Choose Claude Code, Codex or Grok from the CLIs configured on that machine, then choose the model and approval mode appropriate for the task.

A useful request is:

Checkout tax can contain fractional cents. In src/checkout/tax.ts,
round the tax once on the subtotal. Add a regression test for
2997 cents at the US-CA rate. Run the relevant test and explain
which files changed. Leave unrelated files alone.

This specifies the symptom, expected behaviour and a checkable example. The interactive demo above applies a canned version of this task to a sample repository; it does not send the prompt to a model.

Read the response and inspect the diff#

Open the project's Git view. Inspect both the implementation and the new test, including any untracked files. Check that the agent used cents consistently and did not move rounding into every line item.

For this example, the implementation change is small:

return Math.round(subCents * (RATES[region] ?? DEFAULT_RATE));

A test should exercise the rounding behaviour, rather than merely confirm that the function returns a number. For the example input, the expected tax is 217 cents. Your own project's rounding and currency rules may differ; apply its requirements.

The browser demo uses the landing page's editable project and Git model. Tap a changed file to inspect its diff. The sample agent response is a demonstration, not evidence that your real task is correct.

Try the result and run the checks#

Open the dev-server preview for the host and check the affected checkout. Look at the displayed total and try the scenario that previously failed. Our localhost preview guide explains the connection and port setup.

Use the terminal to run the project's relevant test command. If the repository uses Vitest, a targeted command might look like:

npx vitest run src/checkout/tax.test.ts

Use the project's installed test runner and actual test path. Read the terminal output and exit result; an agent's statement that tests passed is worth verifying when the change matters. Run additional checks when the affected code requires them.

Commit the reviewed files#

Stage the implementation and test after reviewing them. Check what is already staged before committing, write a message describing the fix and push only when you are ready. The Git walkthrough covers that flow.

A task can also remain as an uncommitted change for later review at your desk. Its files stay in the host project. For notifications while the agent works, use the completion-notification guide.

Free accounts can access their latest ten agent sessions. Model usage follows the account configured on the host; see pricing for Thumbdesk's separate limits.