Captures a visual representation of the current page viewport or entire page as a base64 encoded image. Side effects: none (read-only). Prerequisites: requires an active Chrome tab. Returns: base64 encoded image in specified format. Use this to visually verify UI state, layout, or rendering. Alternatives: 'inspect_dom' for raw HTML structure, 'get_performance_metrics' for rendering metrics.

Triggers a native mouse click event on a DOM element identified by CSS selector, executing click handlers and form submissions. Side effects: may trigger page navigation, form submission, or modify DOM state. Prerequisites: element must exist and be visible (getBoundingClientRect must return valid coordinates). Returns: success confirmation with click coordinates. Use this to interact with buttons, links, checkboxes. Alternatives: 'fill_input' for text input, 'evaluate_js' for complex interactions.

Focuses an input field via CSS selector and inserts text using native input simulation, triggering input/change events. Side effects: modifies DOM input value; triggers input/change event handlers. Prerequisites: element must exist, be visible, and be an input/textarea or contenteditable element. Returns: success confirmation. Use this to populate form fields, search boxes, text areas. Alternatives: 'evaluate_js' for direct value assignment without events, 'click_element' to focus manually.

Executes arbitrary JavaScript code in the page context, returning evaluated results as JSON-serializable values. Side effects: may modify DOM, state, or trigger network requests. Prerequisites: requires an active Chrome tab; script context must allow execution. Returns: JSON-serialized return value (or error if promise rejected). Use this for dynamic inspection, DOM manipulation, complex interactions. Alternatives: 'inspect_dom' for read-only DOM queries, 'click_element' for UI interactions.

Navigates the current Chrome tab to a specified URL, loading new page content. Side effects: destructive of current page state; discards unsaved work. Prerequisites: requires an active Chrome tab; URL must be valid and accessible (subject to local-only restrictions if enabled). Returns: navigation confirmation. Auth requirements: subject to same-origin policy; may require credentials for restricted URLs. Rate limits: none. Use this to change the current page. Alternatives: 'reload' to refresh current page.

Retrieves the complete HTML document or a contextual snippet around a search query. Side effects: none (read-only). Prerequisites: requires an active Chrome tab with loaded DOM. Returns: full HTML or snippet with context markers. Use this to inspect page structure, find elements by text, or verify rendering. Alternatives: 'evaluate_js' for complex DOM queries, 'capture_screenshot' for visual verification.

Enables the debugger and injects a breakpoint at the first statement of any script loaded after reloading the page. Side effects: reloads the current page (destructive of unsaved state). Prerequisites: requires an active Chrome tab. Returns: confirmation of debugger enablement and page reload. Use this to debug script execution from the page load. Alternatives: 'set_breakpoint' for targeting specific scripts/lines, 'pause_on_exceptions' for exception-based pausing.

Executes the current line of code without entering function calls, pausing at the next line. Side effects: advances debugger execution state. Prerequisites: requires an active, paused debugger session. Returns: confirmation of step execution. Use this to skip function internals during debugging. Alternatives: use 'resume' to continue full execution, 'step_over' enters functions, or 'evaluate_on_call_frame' to inspect state without stepping.

Continues full execution of the debugger from current breakpoint. Side effects: advances code execution until next breakpoint or completion. Prerequisites: requires an active, paused debugger session. Returns: confirmation of resume command. Use this to continue program flow after inspection. Alternatives: 'step_over' or 'step_out' for single-step execution.

Searches all cached script sources for a text pattern and returns matching locations (line and column numbers). Side effects: none (read-only query). Prerequisites: scripts must have been parsed and cached by the debugger. Returns: JSON array of matches with script ID, line/column numbers, and line preview. Use this to locate code before setting breakpoints. Alternatives: 'set_breakpoint' for direct breakpoint placement, 'evaluate_js' for runtime code discovery.

Sets a debugger breakpoint at a specific location, pausing execution when reached. Side effects: modifies debugger state (breakpoint added until removed). Prerequisites: requires an active Chrome tab; target script must be loaded. Returns: breakpoint identifier and location confirmation. Use this to debug specific code paths. Alternatives: 'pause_on_load' for early script execution, 'search_scripts' to find scripts by pattern.

Evaluates JavaScript expressions within the scope of a paused call frame, accessing local variables and call stack. Side effects: read-only by default; can modify state if expression includes mutations. Prerequisites: requires debugger to be paused at a breakpoint with active call frame. Returns: expression result with type and value. Use this to inspect variables and call stack during debugging. Alternatives: 'evaluate_js' for global scope evaluation, 'step_over' to advance without evaluation.

Reloads the current page, discarding all unsaved changes and re-fetching resources from the server. Side effects: destructive of unsaved state; clears dynamic DOM state. Prerequisites: requires an active Chrome tab. Returns: reload confirmation. Use this to refresh page content or reset to initial load state. Alternatives: 'navigate' to load a different URL, 'pause_on_load' to debug reload execution.

Scrolls the page by pixel offset, viewport pages, or to a specific element using CSS selector. Side effects: modifies DOM scroll position (observable but reversible). Prerequisites: requires an active Chrome tab with content. Returns: scroll completion confirmation. Use this to navigate within long pages or bring elements into view. Alternatives: 'click_element' to trigger scroll by clicking, 'evaluate_js' for custom scroll logic.

Removes a previously set debugger breakpoint by its ID, allowing execution to pass that location uninterrupted. Side effects: modifies debugger state (breakpoint deleted). Prerequisites: requires an active, paused debugger session with the breakpoint ID returned from 'set_breakpoint'. Returns: confirmation of breakpoint removal. Use this to clean up breakpoints or disable debugging at specific locations. Alternatives: 'set_breakpoint' to add new breakpoints, 'resume' to continue execution.

Stops and restarts the managed Chrome instance with remote debugging enabled, optionally configuring proxy. Side effects: destructive - terminates running Chrome process and all open tabs; closes debugging connection. Prerequisites: requires CHROME_PATH environment variable or chrome in PATH. Returns: restart success confirmation. Use this to reset browser state, apply proxy settings, recover from crashes. Alternatives: 'reload' to refresh page without restart, 'navigate' to load new content.

Gracefully terminates the managed Chrome instance and closes all debugging connections. Side effects: destructive - kills Chrome process; all open tabs closed; unsaved data lost. Prerequisites: Chrome instance must be running. Returns: termination success confirmation. Use this to clean up resources, prevent zombie processes, or end debugging session. Alternatives: 'restart_chrome' to restart instead of stop.

Retrieves intercepted HTTP/REST requests and WebSocket frames from network activity cache with filtering. Side effects: optionally clears cached logs when 'clear' is true. Prerequisites: requires active Chrome tab with network monitoring enabled. Returns: JSON array of requests/WebSocket frames with optional full details. Rate limits: none. Use this to audit API calls, debug network issues, inspect WebSocket traffic. Alternatives: browser DevTools Network tab, HAR file export.

Retrieves cached console messages including log, warning, error, info levels and uncaught exceptions. Side effects: optionally clears cache when 'clear' is true. Prerequisites: requires an active Chrome tab. Returns: JSON array of console messages with timestamp, level, and text. Use this to debug script errors, monitor page health, inspect exception traces. Alternatives: browser DevTools Console, error logging services.

Captures runtime performance metrics including JS heap size, DOM node count, and layout timing. Side effects: none (read-only snapshot). Prerequisites: requires an active Chrome tab. Returns: JSON object mapping metric names to numeric values (e.g., JSHeapUsedSize, LayoutCount). Use this to monitor memory usage, detect memory leaks, or profile performance. Alternatives: 'profile_page_performance' for detailed tracing, browser DevTools Performance tab.

Records a performance trace of page execution, calculating Core Web Vitals (FCP, LCP, DCL, Load) and identifying Long Tasks (>50ms blocking). Side effects: may temporarily disable cache; impacts page memory/CPU. Prerequisites: requires an active Chrome tab; trace recording uses background bandwidth. Returns: JSON with vitals, blocking time, and top 5 long tasks. Use this to optimize performance, identify bottlenecks, measure cold starts. Alternatives: browser DevTools Performance tab, real user monitoring (RUM).

Activates proxy authentication interception via Fetch domain, supplying credentials for authenticated proxies. Side effects: starts background event listener that auto-terminates after 30s inactivity; initiates pre-warming navigation. Auth requirements: username and password credentials required. Prerequisites: Chrome must be started with proxy-server flag. Rate limits: 30-second timeout per inactivity period. Returns: confirmation of proxy auth activation. Use this after 'restart_chrome' with proxy settings. Alternatives: manual proxy configuration in system settings.

EXPERIMENTAL: Sends raw Chrome DevTools Protocol (CDP) commands to the browser for advanced use cases not covered by specialized tools. Side effects: depends on command; may modify page state, DOM, or trigger navigation. Auth requirements: subject to local-only restrictions if enabled (Page.navigate checked). Prerequisites: requires knowledge of CDP protocol; active Chrome connection. Returns: raw CDP command response as JSON. Use this only when specialized tools inadequate. Alternatives: use domain-specific tools (navigate, click_element, evaluate_js).

EXPERIMENTAL: Retrieves unhandled CDP events from domains not covered by specialized listeners (network, console, etc.). Side effects: none (read-only cache access). Prerequisites: requires active Chrome connection with send_cdp_command or custom domain listeners active. Returns: JSON array of custom events with method, parameters, and timestamp. Use this to see Target, Debugger, or other domain events. Alternatives: domain-specific listeners (get_network_logs, get_console_logs).