---
id: "e163e999-8d63-4fa0-bca9-6bf1485a19b8"
name: "Existing Text Replacement"
micro_summary: "Verified one-line replacement: enter the existing box, visibly select the line, Backspace it, type replacement, Escape, then poll for Saved to Drive."
status: "resolved"
see_also: []
scope: "Verified runbook for replacing the complete contents of an existing one-line Google Slides text box through browser-harness without creating a second box or appending duplicate text."
warnings: "Verified only for replacing a complete one-line text box. Before deletion, require screenshots showing the caret in the intended box and exactly the intended line selected. `click_at_xy()` uses CSS pixels, and `type_text()` must follow an explicit `Backspace`."
---
## Reuse the authenticated tab

```bash
browser-harness <<'PY'
tabs = [t for t in list_tabs() if "docs.google.com/presentation/" in t.get("url", "")]
if not tabs:
    raise RuntimeError("No authenticated Google Slides tab is open")
switch_tab(tabs[0])
wait(1)
print(capture_screenshot())
PY
```

If the wrong slide is active, press `Escape` to leave text editing, then move one slide at a time with `press_key("PageDown")` or `press_key("PageUp")`. Capture a screenshot and verify the ordinal thumbnail highlight; the URL slide ID is not the ordinal.

## Convert screenshot coordinates to click coordinates

`capture_screenshot()` is device-pixel sized while `click_at_xy()` takes CSS pixels. Read the scale:

```bash
browser-harness <<'PY'
print(js("window.innerWidth + \",\" + window.innerHeight + \",\" + window.devicePixelRatio"))
print(capture_screenshot())
PY
```

For an original screenshot coordinate `(sx, sy)`, use `X = sx / devicePixelRatio`, `Y = sy / devicePixelRatio`. Do not use the image viewer's display scaling.

## Enter and verify the existing box

```bash
browser-harness <<'PY'
click_at_xy(X, Y, clicks=2)
wait(.5)
print(capture_screenshot())
PY
```

STOP unless the screenshot shows a caret inside the intended existing text box.

## Select and verify the one line

```bash
browser-harness <<'PY'
press_key("Home")
press_key("End", modifiers=8)
wait(.3)
print(capture_screenshot())
PY
```

`modifiers=8` is Shift. STOP unless the screenshot highlights exactly the full intended line.

## Delete, replace, and verify persistence

```bash
browser-harness <<'PY'
press_key("Backspace")
type_text("REPLACEMENT TEXT")
press_key("Escape")
status = ""
for _ in range(15):
    wait(1)
    status = js("""(function(){return [...document.querySelectorAll("[aria-label]")].map(e=>e.getAttribute("aria-label")).find(x=>x&&x.startsWith("Document status:"))||""})()""")
    if "Saved to Drive" in status:
        break
assert "Saved to Drive" in status, status
print(status)
print(capture_screenshot())
PY
```

The explicit `Backspace` is load-bearing: CDP `type_text()` uses text insertion and did not replace Google Slides' visually selected text in the verified session.