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BERD TASK · 0014 · DO THE WORK

Work with artifacts and MCP apps

An artifact is a file from the conversation opened in a viewer beside it. An MCP app is a small interface an extension renders inside the chat. Both look like part of the transcript; neither is. The artifact is a file on disk that the viewer follows, and the app is a tool that can ask to speak as you. The outcome of this task is that you edit files where edits belong and approve nothing you have not read.

Steps at a glance

  1. Open a file from the conversation in the viewer
  2. Trust the viewer to follow the disk
  3. Edit in your editor, not the viewer
  4. Read an MCP app's message before it goes out as you
  5. Know where a general chat's files land

1. Open a file from the conversation in the viewer

When the agent creates or opens a viewable file, a chip appears in the transcript; opening it puts the file in the side viewer, with a preview and a code view where the file type allows both. If you would rather the viewer opened on its own whenever a viewable file appears, that is a switch in the behavior section of Settings. Which file types render is not stated in the sources; expect markdown and images, and check anything else in the app.

[SCREENSHOT: T14-01 — the artifact viewer]

2. Trust the viewer to follow the disk

Since v0.6.3 the viewer stays in sync with the file on disk: an edit in another program, a write from the shell, a deletion, a temporary read failure that recovers. If the file is deleted the viewer says so, and its actions are disabled until the file reappears. If the file changed but cannot be read, reload it. What you see in the viewer is the file as it is now, not as it was when the agent wrote it — which is the point, and also the reason a viewer that looks wrong usually means the file is different.

3. Edit in your editor, not the viewer

The viewer shows; it does not edit. Open in editor hands the file to your system editor, and the file actions on the row do the small things. Both were broken for a release and were restored in v0.6.4, including in popped-out session windows. How a popped-out window behaves beyond that is not described in the sources.

The reason to keep this discipline: a change made in the real file is seen by the agent on its next read and by the viewer on its next refresh. A change you only imagined making in the viewer is seen by nobody.

4. Read an MCP app's message before it goes out as you

An MCP app renders inline in the transcript; if it cannot, Berd says it is unable to render the app inline and you get the raw result instead. Since v0.6.4 an app that wants to submit a message into the chat as you must ask first. The confirmation names the extension and the tool, tells you they want to send this message as you, and asks you to review the exact text before sending.

[SCREENSHOT: T14-02 — the MCP app confirmation]

Read the text. The message will appear in your transcript as if you had typed it, and the agent will act on it as your instruction. Cancel is free. There is no second gate after this one.

5. Know where a general chat's files land

A chat inside a project has that project's artifact rendering and its folders. A chat with no project — a general chat — saves generated files to the artifact location set in the system section of Settings, and the right rail's artifacts view labels them as belonging to the general chat rather than a project. If a file the agent made is not where you expected, this is the first place to look, before Where did my files go?.

Watch out

The MCP app confirmation is the only thing between an extension and a message sent under your name into the agent's context. Approve it as you would approve sending an email someone else drafted: by reading it, not by recognising the app.

Last checked: Berd v0.6.4, 2026-09-11 — read from source and release notes, not yet tested in the app.

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Reference

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Berd v0.6.4 · 2026-09-11 · source-read
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Guide built with Berd, Claude and Codex · verified against Berd v0.6.4, 2026-09-11 · read from source, not yet tested in the app · Buzz Guide · About · not affiliated with Block