awesome-copilot/extensions/pr-review

PR Review canvas

A personal, read-only GitHub PR review canvas. Paste a direct PR link from github.com or an enterprise *.ghe.com host. The extension retrieves PR metadata, every changed-file record, and the full unified diff directly from GitHub. It saves complete text patches locally, then asks Copilot to group files using their paths and change metadata.

Use

Ask Copilot to open the PR Review canvas. Paste a PR URL and choose Load PR. The link is the only required input. The extension uses a matching GitHub account already available to Copilot or GitHub CLI. It does not ask for or store credentials.

Select a group to see its rationale and files. Expand a file to inspect its full patch, loaded on demand from the local snapshot. Use Ask about group, Ask about file, then enter your question. Answers appear below the question form.

Highlight text within a diff hunk, then choose Add selected lines. The selected lines appear in a separate preview above the question input with their old/new line numbers. The question input stays unchanged. The selection is saved as line positions within the pinned diff hunk; Copilot receives the verified selected lines and the surrounding hunk as context. Choose Ask Copilot to send your question; adding lines does not send a message.

The canvas uses the existing conversation and its model. It does not start another model client, require an API key, install dependencies, or transmit source code to another AI service. Copilot receives file metadata for grouping and only the selected diff context for a question. These turns may wait behind work already running in the conversation.

Review and source boundaries

• This extension does not submit reviews, post comments, approve PRs, or edit code.
• Group checkmarks are local review notes, not GitHub approvals.
• Snapshots include base/head commit IDs. The extension rechecks both against GitHub before publishing groups. Every changed file must belong to exactly one primary group.
• Groups use paths and file metadata, not diff contents. Group rationales must state uncertainty and must not claim code behavior.
• The full PR diff is downloaded directly and split into per-file patches. Patches are fetched from local storage when a file expands; they are not passed through Copilot action arguments. Files without a text patch include an explicit note.
• Reload the PR to retrieve new commits. Refreshing clears local group checkmarks; earlier answers retain their source head SHA.
• Stop waiting invalidates the local request. It does not cancel Copilot's backend work. Late results cannot overwrite a newer request.
• A provider restart marks an unfinished request as interrupted rather than claiming that it completed.
• Maximum diff size: 20 MB. Maximum snapshot size: 24 MB. Maximum changed files: 3,000. Incomplete file enumeration cannot be published as a complete review.

Storage and implementation

The extension is installed in the user's Copilot extensions folder. Review snapshots and answers are stored under pr-review in the current session's workspace. Records are keyed by the canonical PR URL, not by the canvas panel. They survive extension reloads in that session. A different session starts with its own review records.

extension.mjs registers the canvas and agent actions. github.mjs retrieves the PR and full diff from the URL's GitHub host using an existing authorized account. review.mjs owns snapshot validation and persistence. server.mjs serves the UI on loopback. view.html, styles.css, and client.js implement the responsive review UI.

The local server uses a random per-panel URL token, host validation, and same-origin POST checks. Untrusted source and model content is displayed as text, never injected as HTML. Tokens are used only for requests to the matching GitHub host and are not written to snapshots or logs.