The platform, Cowork and Code

Copilot Managed Runtime is Microsoft's hosting layer for line-of-business web apps inside the Microsoft 365 tenant boundary. It entered public preview on 25 September 2026 and already powers the apps built in Copilot Cowork, Copilot Code and Copilot Studio; an SDK and CLI let professional developers and third-party tools deploy to it as well, and Lovable was the launch example. D Whatever you build with, the result is the same kind of artifact: a single-page web app that runs in a Microsoft-hosted sandboxed frame, signs people in with Entra ID, follows the tenant's policies and appears in the Microsoft 365 admin center. App code and assets are served only after sign-in and a permission check, and the host keeps its tokens out of the app code's reach. D

Figure 1 is shown at the top of this part.

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Two more doors matter for developers. Microsoft publishes a coding-agent plugin that adds managed-app skills and slash commands (/create-app, /dev, /deploy, /share, /add-sharepoint, /add-dataverse, /add-workiq and others) to GitHub Copilot, and it also works in other agents that read the open plugin format. DC And on 5 November 2026 the original microsoft/Managed-Apps repository was archived in favor of microsoft/Copilot-Managed-Runtime, with packages moving to @microsoft/cmr-apps and @microsoft/cmr-cli while Learn still shows the old names. C

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Under the chat, a managed app is an ordinary modern web project. A production partner-sales app examined for this guide, created from the chat template, is React and TypeScript on Vite, styled with Tailwind v4 and Radix-based components, built with Bun, and wired to Microsoft services through the @microsoft/managed-apps SDK. O

Each app carries four identifiers, and mixing them up is a common source of confusion: the workspace app id (the folder name in a Code session), the managed app id (the one in the play link), the environment id (your personal developer environment) and the repository id. A Code session can list your apps, read their metadata and load any of them by id. O

The template is also where the hidden capability lives. Every app created from it ships with ready-made controls for pen input (signatures and sign-offs), camera capture (inspections, receipts, asset photos), barcode and QR scanning, 3D model viewing (glTF, GLB, OBJ, STL), PDF export and viewing (up to 25 MB), keyboard shortcuts and a command palette, and a spatial map that needs a spatial services binding to work. Real three.js scenes and simple games are explicitly supported. The template blocks direct use of the underlying libraries so that every app uses the same tested controls. O

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The build pipeline is Git-driven and deliberately split. A git push does not build anything. The platform builds on demand: when someone opens the preview, deploys, or runs a build. The preview URL is stable for each app, always shows the latest successful build of main, and is visible only to people with write access to the repository. The live app changes only on a deploy, which promotes one build; if the latest build failed, a deploy falls back to the last good build with a warning, and you can pin an older commit to roll back without rewriting history. D

The chat surfaces wrap this differently. In Cowork you select Publish, and you must publish again after every change for shared users to get it. D In Code, building saves automatically but never publishes. The app goes live only when you ask Code to publish it, with "Publish it" or "Make it live," and every share is a separate request. D Publishing is not sharing: a published app stays private until you share it.

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Because the URL is the app's, not the tool's. An app is a record in your personal developer environment plus a Git repository, and the play link is keyed to that record. Code and Cowork are two conversational front ends to the same app service: the tools a Code session uses to build, preview, publish, share, connect and bind data are described in terms of Cowork's sign-in cards and Copilot Studio's environments as well, which is a strong sign that one service sits behind all three. O Microsoft's own scenario describes exactly this hand-off: a team builds an app in Cowork, and a developer pulls the code down and keeps building on it without forking it or standing up a separate runtime. D

So when you edit the same app from Code and from Cowork at the same time, you are not editing two copies. You are running two Git clones of one repository, and both can publish to the one live slot.

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Microsoft documents the collaboration model as Git (anyone with edit access clones, pulls before each session and pushes) but does not document what happens when an agent and a developer push to the same app at once. D The table below is what that means in practice, based on Git mechanics and the release history of a production partner-sales app. OI

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• Open Microsoft Copilot (web or desktop) and select Cowork at the top of the page. On Frontier tenants, select the Home tab, where a Chat and Cowork toggle sits in the conversation box. D
• The new navigation pane carries Agents & Plugins, Automations, Workspaces and Projects; it reached Frontier in October and rolls out worldwide in November. Agents & Plugins replaces the older Customize entry point. D
• Home shows your recent tasks, Search, Automations, the model picker and the effort level, plus suggested prompts including Build an app. D

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• Prompts can run to 250,000 characters, enough for a full spec pasted in. D
• Add attachments (+) offers Add work context, Upload images and files, and Attach cloud files and folders; you can also drag files in. Attachments must be under 200 MB. D
• Voice: the microphone button in the input, where your browser supports it. D
• Typing / opens a context picker: the Copilot tab lists earlier chats and Cowork tasks you can attach, so a spec drafted in Chat can feed the App skill. Choose from the picker rather than typing a title. D
• Sources and skills: a picker in the conversation chooses which plugins and skills a request may use; on mobile it is under the attach menu, Skills. D
• Model: the model dropdown defaults to Auto and remembers your choice per device. The current list is in the model table in section 8.1. D
• Effort: a dropdown next to the model picker with Light, Medium (the default), High, Extra High and Max. Higher effort is more thorough, slower and uses more credits; it persists until you change it. D

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• You see each tool step, a streamed reply and interactive cards, with a connection status (Connecting, Connected, Reconnecting, Failed, with Retry). Messages you send while Cowork works are queued, so you can steer without stopping it. D
• Questions arrive as a set of choices: pick one, type your own answer or select Skip; use the arrow keys and Space, then Submit. The task shows Needs user input until you answer. D
• Approvals show the action (Send, Post or Create), Show parameters, Cancel and a risk level for medium- and high-risk actions. More options can skip similar prompts for the session, and for mail and Teams messages you can scope that to one recipient, a domain or always. D
• Revoke any "Approve & don't ask again" choice later under Permissions in the side panel. D
• Pause comes in two strengths: soft (after the current step) and hard (immediately), with Resume and Cancel. D

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• The side panel shows Progress, the Input and Output folders (Download and Preview per file; Download All makes a ZIP of up to 50 files and 500 MB), and Skills, Schedule and Permissions. D
• Tasks can be filtered by Needs your input, In progress, Complete, Automations and Unread. D
• Projects are private workspaces: create one with + next to Projects, give it a name and color, and use Edit instructions. Project instructions take precedence over your global instructions, so one Project per app is the cleanest way to give every session the same spec, schema and rules. Files can't yet be removed from a project's outputs. DI

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• The Automations page has Runs and Manage schedules and a Create button; finish with Activate, or Activate and run now to watch the first run. You can keep up to 25 scheduled prompts, and Microsoft limits how often they run. D
• Event triggers use a "Set up trigger?" card (When, Run in, What it does) and can fire on matching mail or Teams posts, including when you're @mentioned. Triggered actions draft for your approval by default. D
• For app owners this is the cheapest monitoring there is: a weekday check that opens the app, compares totals with the source and messages you the differences (Part 23). I

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• Preferences hold your instructions (up to 20 KB); type / inside them to reference a skill, file, person or meeting. D
• Plugins has Installed, Discover and Upload plugin; plugins installed here are also available to Code. D
• Skills has Your skills and Built-in (the App skill is listed as "App (Frontier)"). Create one with Add, Create new, or upload a SKILL.md; share it with Only you or Specific users in your organization, and Re-share after editing. Limits: 50 skills, 1 MB per SKILL.md, 20 companion files and 10 MB per skill; Cowork scores each skill from 0 to 100 for trigger clarity, specificity, scope and robustness. D
• No memory screen is documented for Cowork; use instructions and Projects for anything every session must know. DI

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Cowork on the web can drive a hidden Microsoft Edge tab that uses your own sign-in, which is how it can open your live app as a real user. An admin turns on the Cowork Browsing tenant setting; you need Edge 152.0.4191.53 or later and a one-time "I understand" consent; it works on the web only, not in the desktop or mobile apps, and your computer must stay awake. D

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• Check prerequisites: a Microsoft 365 Copilot license, Cowork access, usage-based billing and Frontier membership. D
• Start: describe the app ("Build an app to run my daily scrum with my team"), or type /app, a space, and paste your prompt. Attach the spec, spreadsheets and screenshots with the + menu. Cowork invokes the App skill, and it can generate the data schema in a supported connector instead of starting on placeholder data. D
• Approve: review and approve requests to reach your lists. The first build also creates your personal developer environment, which takes a few minutes. D
• Test: open the app from the conversation or the editing screen and preview each change. D
• Publish: your app saves as you work, but users see a change only after you select Publish, every time. D
• Share: open the app for editing and select Share to generate a sharing link, or add people or groups in the input box. If the app will move to another environment, move it before you share it (Part 15). D
• Update later: the app lives in a conversation usually named Edit Application or Edit Application Settings. Use More options, Rename or Pin to find it again, chat your changes, review the preview and Publish. You can also open the app in Copilot Studio. D
• Version history and rollback: no version screen is documented in Cowork, although every change is a Git commit underneath. Roll back from Code or the CLI by redeploying an earlier commit (Part 20). DI
• Delete: "Delete my app named Project Tracker." Deletion is permanent; admins can block an app instead. D

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• Open the Microsoft Copilot app, or go to copilot.cloud.microsoft, and select Code in the tab switcher at the top (Part 3 explains when it is missing). D
• The home screen has a task input, suggested prompts such as Build a dashboard and Automate a workflow, Create new to start a project, Search to find an earlier one, Recents, and the model picker. Projects save automatically. D

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Admin defaults also matter: components aren't pre-installed, auto-approve is on, execution location is cloud only, and the GitHub connection is off until an admin allows GitHub.com, GitHub Enterprise or both. D One community tester reported that local mode ran without a sandbox in his setup, against Learn's statement that secure local execution is on by default, so check the setting before working on sensitive folders. C

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• + uploads files or attaches work context; drag in CSV files, spreadsheets, images, documents, PDFs and presentations (up to 200 MB per file), or paste text. In a local session you can also open an existing folder. D
• Work context: with your permission, Code draws on your documents, email, meetings and calendar through Work IQ, and asks clarifying questions before it builds. D
• Models: a model picker, with Auto as the default in cloud sessions. The current list is in the model table in section 8.1. D

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• Interactive (the default) is step-by-step collaboration; Plan develops a plan you can question and refine before any change; Automatic runs end to end and is available only when Always allow is on. Automatic doesn't grant unrestricted access or remove every approval. D
• By default Code asks before it makes network calls, uses extensions and MCP servers, runs shell or terminal commands, or reads and writes files outside the project. D
• Always allow stays on, for existing and new sessions, until you turn it off. Turn it on for a focused run, then off again. DI

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• While Code works you see its progress steps; it may stop to ask questions, often as multiple choice. DO
• Preview shows the running app; select an element in the preview to point Code at it instead of describing it. D
• Code view shows the generated files; editing them by hand is local only. D
• Undo by asking Code to revert to an earlier version; for an app, that means redeploying an earlier commit (Part 20). DO
• Export a project as a .zip. D

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• Building saves automatically but never publishes. The app goes live only when you ask Code to publish it. Ask: "Publish it" or "Make it live," and check the reply for the live link before you tell anyone. DI
• Share by asking: "Share it with the Partner Sales group so they can use it." Code resolves the people or groups and grants use or edit access (Part 15). A static page, as opposed to an app, can be shared as an organization-scoped link in cloud sessions. DO
• Delete by asking Code to delete something it created. D
• GitHub: connect your account from the side navigation to work with repositories, warm-start from one, open draft pull requests and see their status in My Work; creating repositories is local only. D

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Plan mode is documented under Get started, Choose a working mode. Across the industry, plan modes promise different things; only one vendor documents a strict guarantee that nothing changes until you approve, so treat plan approval as a checkpoint rather than a sandbox. DC

The most effective use is to make the plan produce a file. Ask the plan to write or update DESIGN.md with numbered items, review it, then build one item per change. A plan that lives only in the chat can be lost when the session ends; section 8.1 covers what Code remembers. I

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There are three answers, and they are often confused.

You can see it. The canvas beside the chat shows the live preview, and you can select an element to point the agent at it. D

The agent can see it, with a script. In the cloud session tested on 7 November 2026, the interactive browser tool reported that local browsing was not enabled for the workspace. But the sandbox ships a full headless Chromium with Playwright (they are there to render documents), and a short script can open a page, click a button, read the result, resize to phone width and save screenshots that the agent then inspects. The figure shows the probe. The limits are real: the headless browser cannot sign in as you and connector calls do not work outside the host, so it suits layout and flow checks against fixture data, not end-to-end checks against live data. O

Figure 2 is shown at the top of this part.

Cowork can see the live app. Cowork on the web, running in Microsoft Edge 152 or later, can drive a hidden Edge tab with your own sign-in, so it can open the play link and walk a checklist with real data and your real permissions. Your admin must enable Cowork Browsing, and the desktop app does not support it. D

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• Open an interactive browser: switched off for the workspace. O
• Sign in to the live app as you, or call connectors outside the preview host. OI
• Push directly to the app repository in some sessions, where the push was refused as "disabled"; the publish step pushed and deployed instead. O
• Create a tenant-wide share link, which only the CLI offers. OD
• Accept hand edits in the code view for a cloud session; that is local only. D
• Not documented by Microsoft for Code at this release: slash commands, keyboard shortcuts, a diff view, a terminal pane, an in-session cost display and specialist sub-agents. D In the session tested, Code nevertheless ran shell commands and dispatched an independent reviewer and parallel researchers on request. O A /cost command is not documented for Code I; builders report that it works there C.

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The map below lists what exists, how sure we are, and the words that trigger it.

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Models in each tool, as of 7 November 2026

This is the only model list in the handbook; other parts link here.

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• Gives you a choice of working mode, including Plan, and a model picker that includes Microsoft's MAI-Code-1-Flash.
• Runs real engineering tools: a shell, Git, package installs, type checks and test suites, and a headless browser it can script.
• Works on folders on your own machine (local sessions), with hand edits in the code view.
• Connects to GitHub for branches, commits and draft pull requests, and shows your issues and reviews in My Work.
• Dispatches specialist sub-agents on request: an independent reviewer, a security reviewer, a deep researcher, or several builders in parallel. O
• Shares static pages as organization-scoped links, separate from managed apps.

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• Opens real websites, including your live app, in a hidden Edge tab with your own sign-in, and asks before sensitive actions.
• Runs scheduled prompts and reacts to email and Teams events, which makes it the natural home for recurring checks on an app.
• Handles the Microsoft 365 work around the app: finding the people and files, drafting the announcement, booking the review, writing the training deck.
• Lets you add up to 50 custom skills (stored as SKILL.md files in OneDrive) and share them with colleagues.
• Offers effort levels, from Light to Max, and documents /cost for spend so far; a /cost command is not documented for Code.
• Reaches you on mobile, in Outlook and in Teams.

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• The runtime, the artifact, the play link and the admin inventory entry. D
• The app service and the app records: either can load an app the other built. OD
• The plugins from the Microsoft 365 App Store and Microsoft 365 work context. D
• The connectors and policies that apply to the app at run time. D
• Frontier enrollment and Copilot credit billing for build work. D

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