Chromeflow vs Firefox Devtools MCP

list_tabs

List all open tabs in the current window with their index, title, and URL. Use this before switch_to_tab if you're not sure which tab to switch to.

close_tab

Close a tab by number, URL substring, or title substring. Mirrors switch_to_tab's matcher. Defaults to closing the ACTIVE tab when no query is given. Use this to clean up the tab pile after a multi-step workflow.

close_other_tabs

Close every tab in the current window EXCEPT the active one (or any tab matching keep_query). Use at the end of a session to tidy up; do NOT use mid-flow if you may need to return to one of the closed tabs.

interactive_snapshot

Compact, accessibility-style list of the page's ACTIONABLE elements — each as [role] name — selector. Use this INSTEAD of get_page_text or take_screenshot when your goal is to ACT (click / type / select), not to read prose: it is far cheaper in tokens than dumping page text, and every line gives a ready-to-use selector for click_element / type_text. Pierces open AND closed shadow roots (Reddit faceplate-*, Radix/Stencil/Lit), which a raw accessibility tree misses. Returns the top elements by document order; pass max to widen. For reading article/body text, still use get_page_text.

take_screenshot

Capture a screenshot of the active tab. By default the image is returned to the agent inline UNLESS it exceeds ~500KB base64, in which case it's saved to a temp file and the path is returned instead (preserves the agent's context window). Set inline="always" to force inline regardless of size, or inline="never" to always write to a file. Set save_to or copy_to_clipboard to also share the image with the user. Reserved for cases where DOM lookup has already failed — use get_page_text and find_text for reading content. Refuses fast on pages that are in fullscreen mode (captureVisibleTab hangs there). Exit fullscreen first with execute_script("document.exitFullscreen()") or pass allow_fullscreen: true if you really must try anyway.

capture_terminal

Capture a screenshot of the terminal window (Terminal, iTerm2, Warp, VS Code, Ghostty, etc.) and save it as a PNG. Use this when you need a screenshot of terminal output — e.g. test results, build logs, or command output — to upload to a form via set_file_input. Auto-detects the terminal app. Returns the image to Claude AND saves the PNG file. The saved file path can be passed directly to set_file_input(hint, file_path) to upload it.

clear_overlays

Remove all highlights and callout annotations from the current page.

get_form_fields

Inventory form fields on the active page (inputs, textareas, selects, CodeMirror editors). Sorted top-to-bottom by y-position; includes fields below the fold. Pass `query` to filter+rank by label/placeholder/aria-label/name/id (the old find_input behavior — match strength reported as aria-eq / placeholder-eq / label-text-eq / name-eq / id-eq / *-includes / fuzzy-text-walk). Pass `exact: true` to refuse fuzzy text-walk matches. Pass `only_empty: true` to filter the inventory to required-but-empty fields. This is the "why is Submit disabled" diagnostic: it returns just the required fields that haven't been filled yet (or radios/checkboxes still unchecked) and skips everything that's already populated. Required-ness is detected via the `required` attribute, `aria-required`, or a trailing `*` in the associated label text.

type_text

Type text into the currently focused element via CDP keystrokes (produces isTrusted=true events). Use when fill_input fails because the page validates isTrusted (CodeMirror/Monaco/Ace editors, shadow DOM inputs, isTrusted-gated forms). Pass `into_selector` to focus the target before typing (shadow-piercing CSS) — combined with `clear_first: true`, this collapses the old "wait_for_click → execute_script selectAll → type_text" pattern into a single call. Pass `frame: "iframe.selector"` to type into a same-origin iframe's first editable element. **Post-type landing verification, always on.** Whether you pass `into_selector` or type into whatever's already focused, type_text reads back the target element after typing and returns `landed:false` (success:false) if the text did NOT actually stick — never trust a bare "Typed N characters" without checking this. Two known causes: (1) a rich-text editor's own state machine reverts the keystrokes (TipTap/ProseMirror — auto-recovers via `document.execCommand('insertText', ...)`, message records "recovered via execCommand insertText"); (2) tenant-level anti-automation discards synthetic keystrokes outright with zero visible error (seen on some Workday tenants) — for a plain `<input>`/`<textarea>` this attempts a native-value-setter recovery, and if that ALSO fails, reports `landed:false` so you stop and report the wall instead of proceeding on a false premise.