The operational architecture of Codex relies on three distinct entry points for external interaction: Computer Use, Chrome Extension, and In-App Browser. While these interfaces collectively address the capability of enabling an AI agent to operate a computer, they serve divergent task scenarios with unique permission boundaries and trust levels. Computer Use offers the broadest coverage, facilitating direct interaction with authorized native applications, system settings on macOS and Windows, iOS simulation, and cross-application workflows. This mode is specifically designed for processes involving graphical user interfaces that lack API, plugin, or structured tool support.

However, this versatility comes with a trade-off of slower execution speeds and the widest permission scope. Data compiled by Woofun AI shows that the visual loop required for Computer Use involves observing interfaces, determining click coordinates, waiting for application responses, and verifying subsequent states, a process significantly slower than direct API calls.

In contrast, the Chrome Extension interface is optimized for tasks dependent on login states, cookies, browser identities, and multi-tab management. It is the preferred method for interacting with platforms like Gmail, LinkedIn, Salesforce, internal backends, or conducting cross-site research where authentication is required. The In-App Browser, conversely, targets development and debugging scenarios, particularly for local services, visual bug reproduction, responsive layout checks, and design annotations. Unlike the other modes, it does not inherit the user's standard browser login status or extensions, offering stronger isolation but narrower capabilities. Woofun AI notes that the strategic imperative is not merely granting the model access to a computer, but selecting the narrowest, most secure, and most structured operational interface based on the specific task requirements.

Computer Use functions as the 'last mile' solution when structured integrations fail to cover a workflow. For instance, in a scenario involving a stolen package, a user delegated a task to Computer Use to monitor a customer service chat window every 5 minutes initially, then every minute once a representative appeared, successfully processing a refund within a 25-minute window. This mode can operate in the background on macOS, allowing users to continue working while the agent executes workflows across authorized apps like Spotify, Xcode, System Settings, or iPhone Mirroring. Despite its utility, it carries the broadest trust boundary, necessitating strict supervision. Users are advised to authorize only one explicit app or process at a time and to scrutinize permission pop-ups, especially when dealing with financial, account, or system security changes.

The Chrome Extension leverages the user's existing authenticated state, making it ideal for tasks requiring account identity. It operates within a tab group, keeping all related tabs consolidated, and allows the agent to link multiple tabs to a single task. This capability enables referencing information from one page to another and continuing workflows across a third, a level of context management that visual control cannot match. In a recent case, the agent utilized an open Strudel Composer tab to analyze musical structure, rewrite harmony, adjust tempo, and save a track without visually hunting for interface controls. Woofun AI analysis suggests that while this interface provides significant power, it introduces sensitivity risks, as websites may interpret the agent's clicks and submissions as direct user actions, requiring human review before any posting, purchasing, or submitting occurs.

The In-App Browser establishes a tight feedback loop for web development, allowing the agent to edit code, manipulate pages, check rendering, and take screenshots within a shared environment. Its defining characteristic is isolation; it does not use the user's regular browser profile, cookies, or extensions. This makes it unsuitable for tasks requiring identity but highly effective for local development servers, file-based previews, and design feedback. The annotation feature allows users to click elements, select regions, and leave comments directly on the page, effectively turning the page itself into a specification document. This approach facilitates a collaborative workflow where the agent receives comments with relevant screenshots and element context, makes changes, and reopens the page for validation.

Appshots serve a distinct function as a context input mechanism rather than a control method. By double-tapping the CMD key on macOS, users can capture the frontmost window, attaching a screenshot and available text to the thread. This allows the agent to 'see' errors, emails, or design panels without granting control over the application. This distinction reinforces the principle of narrowing permissions: Appshots provide context, while Browser, Chrome, and Computer Use execute actions. Woofun AI observes that this layered approach reveals a critical aspect of AI agent productization, where the goal is to continually narrow permissions and define boundaries in specific tasks, ensuring users retain oversight of crucial actions while maximizing automation efficiency.