chrome-devtools_fill fails to clear existing input values and loses targeting focus in sequential calls

[luanweslley77]

Description of the bug

The chrome-devtools_fill tool exhibits inconsistent behavior when interacting with multiple form inputs in sequence. Specifically:

1. Failure to Clear: It does not clear existing text in an before typing the new value. In environments like PHP where form fields persist after a failed submission (sticky forms), the new value is appended to the old one.
2. Targeting/Focus Issue: In sequential calls (e.g., filling Email then Password), the tool occasionally directs the second input's value into the first input field, leading to data corruption (e.g., emailpassword inside the email field).

Reproduction

Steps to reproduce the behavior:

1. Access a page with a form containing at least two inputs (Email and Password).
2. Ensure the first input already has a value (e.g., "user@test.com").
3. Call chrome-devtools_fill for the first input with a new value.
4. Call chrome-devtools_fill for the second input with a different value.
5. Observe that the first input now contains both its original value and the second input's value concatenated.

Expectation

1. chrome-devtools_fill should strictly clear the target element's value before performing any input.
2. The tool must ensure the target element (identified by UID) has focus and is the sole recipient of the value payload, regardless of previous tool calls in the same session.

MCP configuration

{
"$schema": "https://opencode.ai/config.json",
"mcp": {
"chrome-devtools": {
"type": "local",
"command": ["npx", "-y", "chrome-devtools-mcp@latest"]
}
}
}

Chrome DevTools MCP version

0.15.1

Chrome version

144.0.7559.109

Coding agent version

OpenCode 1.1.49

Model version

gemini-3-flash-preview

Chat log

No response

Node version

v22.22.0

Operating system

Linux

Extra checklist

• I want to provide a PR to fix this bug

[luanweslley77]

After deeper testing I discovered that chrome-devtools_fill
is dispatching input events on multiple fields when targeting
a password input.

I injected listeners via chrome-devtools_evaluate_script:

() => {
const email = document.querySelector('#email');
const pwd = document.querySelector('#password');

email.addEventListener('input', () => console.log('EMAIL changed'));
pwd.addEventListener('input', () => console.log('PASSWORD changed'));
}

Then executed:

chrome-devtools_fill on the password UID.

Result:

EMAIL changed
PASSWORD changed

This suggests the tool may be triggering credential autofill
behavior internally instead of strictly targeting the UID element.

The DOM structure is correct and evaluate_script targeting
#password does NOT reproduce the issue.

Possibly related to login heuristics or accessibility grouping.

[luanweslley77]

After deeper testing I discovered that chrome-devtools_fill is dispatching input events on multiple fields when targeting a password input.

I injected listeners via chrome-devtools_evaluate_script:

() => { const email = document.querySelector('#email'); const pwd = document.querySelector('#password');

email.addEventListener('input', () => console.log('EMAIL changed')); pwd.addEventListener('input', () => console.log('PASSWORD changed')); }

Then executed:

chrome-devtools_fill on the password UID.

Result:

EMAIL changed PASSWORD changed

This suggests the tool may be triggering credential autofill behavior internally instead of strictly targeting the UID element.

The DOM structure is correct and evaluate_script targeting #password does NOT reproduce the issue.

Possibly related to login heuristics or accessibility grouping.

When chrome-devtools_fill targets a password field while another
input has autofocus, keyboard/input events are dispatched to the
focused element before focus is transferred.

Removing autofocus or clicking the target before fill avoids the issue.
evaluate_script does not reproduce the behavior.

[OrKoN]

Thanks for reporting! the fix will be out shortly!