You are adding multiple chrome.runtime.onMessage.addListener calls throughout this file. In a Chrome extension's background script, only one onMessage listener can be active at a time. Each new call to addListener overwrites the previous one, which will cause message handlers for actions like fetchClusters to be ignored. All message handling logic should be consolidated into a single onMessage listener, using a switch statement or an if/else if chain on request.action to delegate to the correct handler.

acceptNode is called here, but it's defined in the background script's scope. This function getPageContent is executed in the tab's context where acceptNode will be undefined, causing a ReferenceError. The acceptNode function definition should be moved inside getPageContent to ensure it's in the correct scope when the script is executed.

The clusterId is cast to any to satisfy the function's return type signature Promise<[number, number[], string][]>. However, clusterId is a string (likely a UUID), not a number. This bypasses type safety and can lead to bugs. The type signature should be updated to reflect the actual data type.

The return type of fetchClustersFromMantis (line 31), the type of clusterGroups (line 146), and the parameter for createTabGroupsFromClusters (line 6) should all be changed from [number, number[], string][] to [string, number[], string][]. Then, this as any cast can be safely removed.

You are using innerHTML to inject an error message into the DOM. The error.message can originate from the backend and could potentially contain malicious HTML, leading to a Cross-Site Scripting (XSS) vulnerability. You should use textContent to safely display the error message as plain text.

            modal.innerHTML = `
                <div style="text-align: center;">
                    <div style="font-size: 48px; margin-bottom: 16px;">⚠️</div>
                    <h2 style="margin: 0 0 12px 0; font-size: 24px; color: #1a1a1a;">Failed to Organize</h2>
                    <p id="mantis-organize-error-message" style="margin: 0 0 24px 0; color: #666; font-size: 15px;"></p>
                    <button id="close-error" style="
                        background: #f0f0f0;
                        color: #666;
                        border: none;
                        padding: 12px 28px;
                        border-radius: 8px;
                        font-size: 15px;
                        font-weight: 600;
                        cursor: pointer;
                    ">Close</button>
                </div>
            `;
            const p = modal.querySelector('#mantis-organize-error-message');
            if (p) {
                p.textContent = error.message || 'An error occurred while organizing tabs.';
            }
            modal.querySelector('#close-error').addEventListener('click', () => {
                overlay.style.opacity = '0';
                setTimeout(() => overlay.remove(), 300);
            });

The injectUI function is defined with an optional tabsMap parameter, which is not part of the injectUIType interface. When this function is called from createSpace, the tabsMap argument is not provided, so it is undefined. The check if (!tabsMap) return null; on line 432 then causes the function to exit immediately, rendering this UI injection logic unused. Additionally, the showOrganizationPrompt function already seems to handle the UI for organizing tabs, making the purpose of this injectUI function unclear. The implementation needs to be revisited to either correctly wire it up or remove it if it's redundant.

The WebSocket message data is parsed into an any type (JSON.parse(event.data)). This undermines the benefits of TypeScript. To improve type safety, code clarity, and maintainability, you should define interfaces for the expected WebSocket message structures and cast the parsed data to that type. For example:

interface Cluster {
  id: string;
  label?: string;
}

interface Point {
  id: string;
  cluster?: string;
  metadata?: {
    tab_id?: string;
  };
}

interface WsMessage {
  type: 'cluster' | 'points' | 'finished';
  clusters?: Cluster[];
  points?: Point[];
}

const data: WsMessage = JSON.parse(event.data);