melodic-software Purpose
Claude Code ships computer use as a built-in MCP server whose tool descriptions already cover the mechanics: actions, the allowlist gate, permission tiers, the ladder that prefers a dedicated MCP over Chrome over screen control. This skill does not restate any of that.
It carries only what the surface does not tell you and the model cannot derive: the shape of the screenshot budget, the failure modes that look like tool bugs but are environment state, and the per-OS input quirks that are invisible until they bite.
Arguments
Parse $ARGUMENTS. Each value names one reference spoke; there are exactly three.
| Argument | Loads |
|---|---|
| (none) | Nothing. Answer from the symptom guide below, and load a spoke only if the symptom needs it. |
screenshots |
reference/screenshots-and-zoom.md. Pixel budget, zoom, resolution guidance |
failures |
reference/failure-diagnostics.md. The idle timer, capture and input ladders, probes |
quirks |
The per-OS file for the machine you are on (see below) |
Symptom guide (no file load needed)
| Situation | Answer |
|---|---|
| Screenshot looks low-resolution | Expected. Fixed pixel budget, no setting. Use zoom. → screenshots-and-zoom.md |
| Small text unreadable after downscale | zoom the region. It re-captures at full resolution. Do not lower display resolution. |
empty capture (0x0) |
Environment, not a tool bug. Walk the ladder → failure-diagnostics.md |
| Input returns a UIPI error | An elevated or secure-desktop process holds the foreground. Not recoverable by retrying. |
| "not in the allowed applications and is currently in front" | A background app stole focus. Retry with screenshot as the batch's first action. |
| Session died partway through a long task | Idle timeout. Claude's own input does not reset it → failure-diagnostics.md |
| A synthesized key does nothing in a menu | Shell-owned surfaces differ from in-app menus → your OS's quirks file |
Per-OS quirks
Load only the file for the machine you are on:
| Platform | File |
|---|---|
| Windows | reference/windows-quirks.md |
| macOS | no quirks file ships. See the verification gap below |
Verification gap. Every empirical claim in this plugin was measured on Windows 11 with the Claude Desktop surface. macOS is supported by the platform and by this plugin's platform-neutral content, but no macOS quirks file ships because none has been verified. A macOS user gets the platform-neutral material and no fabricated specifics.
Surfaces differ. Know which one you are on
Computer use is not one thing, and guidance written for one surface is wrong on the other. The rows below restate the "Differences from the Desktop app" table on computer use from the CLI, verified 2026-09-06 against Claude Code 2.1.263 and that page as fetched that day. Recheck when that page drops the differences table, when a row in it changes, or when a release note names computer use on either surface.
| Claude Code CLI | Claude Desktop | |
|---|---|---|
| Platforms | macOS only | macOS and Windows |
| Enabling | /mcp → enable computer-use |
Settings → General |
| Denied-apps list | not available | configurable |
So a Windows session using computer use is on the Desktop surface by construction. Check before applying any surface-specific advice.
Gotchas
- The screenshot budget is not a scale factor. Two machines with different displays land at the same megapixel count, not the same ratio, which is why "just use a smaller monitor" does not produce a sharper screenshot. See the reference file before advising anyone on resolution.
zoomre-captures; it does not crop. It therefore fails when capture is failing, and it recovers genuine detail when capture is healthy. Both follow from the same fact.- A tool error naming an unexpected app is the safety gate working, not a defect. Nothing was typed into the wrong window. Re-screenshot and retry rather than escalating.
- On a multi-monitor machine, a launched app can be missing for two opposite reasons. It
opened on a display you are not capturing, or you are pinned to the display it did not open
on. Chasing the first creates the second; reset to
autobefore sweeping. - Elevated processes cannot be driven at all. UIPI blocks synthesized input from a lower-integrity process regardless of any grant. Ask the operator to handle those windows.