[Feature]: Deep link (t3code://checkout-pr) to open the PR-checkout dialog from outside the app

[achtan]

Before submitting

• I searched existing issues and did not find a duplicate.
• I am describing a concrete problem or use case, not just a vague idea.

Area

apps/desktop

Problem or use case

My old terminal workflow was a one-liner: paste a PR link or branch name → land in a worktree for it. T3 Code already has the in-app equivalent (paste a PR URL into the BranchToolbar branch selector → PullRequestThreadDialog → local/worktree mode), which is great — but it can only be triggered by clicking through the UI on a fresh draft thread.

There is no outside-in entry point. Coming from a PR page in the browser, a Slack message, or a terminal, I can't hand T3 Code a PR reference and have it open the checkout flow. I have to switch to the app, find/create a draft thread, open the branch picker, and paste.

Proposed solution

A deep link that opens the PR-checkout flow with the reference pre-filled, e.g.:

t3code://checkout-pr?ref=https://github.com/org/repo/pull/123

Behavior: focus/launch the app, open (or create) a draft thread in the current project, and open PullRequestThreadDialog with initialReference set — the user just picks local vs. worktree.

Most of the plumbing already exists:

• The Electron app already registers a protocol client (setAsDefaultProtocolClient in apps/desktop/src/electron/ElectronApp.ts) — missing only the URL routing for this action.
• PullRequestThreadDialog already accepts an initialReference prop.
• Reference parsing (apps/web/src/pullRequestReference.ts) already normalizes GitHub/GitLab/Azure URLs, #123, and even pasted gh pr checkout 123 commands.
• The backend RPC git.preparePullRequestThread does the resolution + branch + worktree work.

Why this matters

Enables composition with everything outside the app: browser extensions, Raycast/Alfred, and trivial shell functions like w() { open "t3code://checkout-pr?ref=$1"; }. For PR-review-heavy workflows, "paste link → worktree thread" becomes one action instead of five clicks, and T3 Code stays the owner of worktree lifecycle (no external git worktree juggling, avoids #1714-style mismatches).

Smallest useful scope

Handle the single deep-link route: parse ref, focus the app, open the PR dialog pre-filled in the active project's draft thread. No CLI, no branch-name variant, no thread auto-start — the dialog's existing UX handles the rest.

Alternatives considered

• Pasting the link into the BranchToolbar manually — works, but requires app focus + navigation to a draft thread first.
• Creating the branch externally (gh pr checkout) and picking it in the branch selector — two tools, and externally-created worktrees have issues ([Bug]: Externally created Git worktrees are treated as “Local” #1714).
• A full CLI (t3code checkout-pr <ref>) talking to the server's WS RPC — more powerful, but much larger scope; the deep link covers most of the value.

Risks or tradeoffs

• Deep links are an untrusted input surface — the handler should treat ref as a plain string fed to the existing parser/dialog (user still confirms in the dialog before anything runs), never auto-execute checkout.
• Ambiguity when multiple projects/windows are open — first pass can just target the focused window's active project.

Examples or references

• Prior art: vscode:// / cursor:// deep links, Linear's linear:// routes.
• Related: [Bug]: Externally created Git worktrees are treated as “Local” #1714 (externally created worktrees treated as "Local") — this proposal sidesteps that class of problem by keeping worktree creation inside T3.

Contribution

• I would be open to helping implement this.

[juliusmarminge]

Note

Grok responding on behalf of Julius.

This shipped in #18454: T3 Code links (https://app.t3.codes/new?..., t3code://new?..., t3code://threads/<environmentId>/<threadId>?..., and pr=owner/name/N) now open the app with a prompt drafted and ready to send. See docs/user/prompt-links.md for the details. Closing as resolved.