Add createFile param to the switch submode command #3867

jurgenwerk · 2026-01-20T10:01:22Z

This PR addresses a user experience issue where:

User is in interact mode and opens the AI assistant and tells it to generate something (e.g. "make me a tic tac toe game")
The assistant will switch to code mode and open the index card, then proceed with ai generation and once user accepts the patch to create file(s) nothing happens, they still see the index card.

This PR adds an optional boolean param createFile to switch mode command where it will create the file the assistant is about to generate. The user will be transitioned to code mode, seeing a blank file until the AI assistant is done generating the code.

The changes in this PR alone don't fix the mentioned issue yet - there will be another PR in the skills repo to teach the LLM when to use createFile parameter (I have it almost ready and confirm it works with all of the above).

Note

Introduces optional file creation when switching to code mode and centralized non-conflicting filename handling.

Adds createFile to SwitchSubmodeInput and new SwitchSubmodeResult (returns codePath when filename changes)
Updates switch-submode to optionally create a blank file via write-text-file when entering "code" from "interact"; updates code path accordingly
Enhances write-text-file with useNonConflictingFilename, realm validation, safer existence checks, and returns FileUrlCard
Extracts findNonConflictingFilename to utils/file-name and refactors patch-code to use it
UI: suppresses result card display for switch-submode* commands in matrix message renderer
Adds comprehensive tests for new behaviors and edge cases

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github-actions · 2026-01-20T10:08:39Z

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github-actions · 2026-01-20T10:24:35Z

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1 files ±0 1 suites ±0 1h 41m 56s ⏱️ -50s
1 912 tests +9 1 895 ✅ +9 17 💤 ±0 0 ❌ ±0
1 927 runs +9 1 910 ✅ +9 17 💤 ±0 0 ❌ ±0

Results for commit 2920284. ± Comparison against base commit 2167921.

♻️ This comment has been updated with latest results.

…h-ai-it-will-sometimes

Copilot

Pull request overview

This PR enhances the AI assistant's user experience by adding a createFile parameter to the switch-submode command. When switching from interact mode to code mode, the assistant can now create a blank file immediately, allowing users to see an empty file instead of an index card while the AI generates code.

Changes:

Added createFile boolean parameter to SwitchSubmodeInput and introduced SwitchSubmodeResult card definition for handling filename conflicts
Implemented file creation logic in switch-submode command with automatic conflict resolution when target files already exist
Extracted filename conflict resolution logic to a reusable utility function and refactored patch-code command to use it

Reviewed changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
packages/base/command.gts	Added `createFile` field to `SwitchSubmodeInput` and defined `SwitchSubmodeResult` card for communicating filename changes
packages/host/app/commands/switch-submode.ts	Implemented file creation logic with conflict resolution when switching from interact to code mode
packages/host/app/utils/file-name.ts	New utility function for finding non-conflicting filenames
packages/host/app/commands/patch-code.ts	Refactored to use shared filename conflict resolution utility
packages/runtime-common/ai/prompt.ts	Added instruction generation for AI when filename conflicts occur
packages/host/app/components/matrix/room-message-command.gts	Hide result cards for switch-submode commands in the UI
packages/host/tests/integration/commands/switch-submode-test.gts	Added tests for file creation and conflict resolution scenarios
packages/ai-bot/tests/prompt-construction-test.ts	Added test for AI instruction when filename conflicts occur

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packages/host/app/commands/switch-submode.ts

packages/host/app/utils/file-name.ts

packages/host/app/commands/switch-submode.ts

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

…h-ai-it-will-sometimes

jurgenwerk · 2026-01-21T11:26:14Z

Accompanying PR: cardstack/boxel-skills#44

lukemelia · 2026-01-22T16:10:55Z

packages/host/app/commands/switch-submode.ts

+          let { status, content } = await this.cardService.getSource(codeUrl);
+          if (status === 404) {
+            await this.cardService.saveSource(codeUrl, '', 'create-file');
+          } else if (status === 200) {
+            if (content.trim() !== '') {
+              let nonConflictingUrl = await findNonConflictingFilename(
+                codeUrl.href,
+                (candidateUrl) => this.fileExists(candidateUrl),
+              );
+              let newCodeUrl = new URL(nonConflictingUrl);
+              await this.cardService.saveSource(newCodeUrl, '', 'create-file');
+              finalCodeUrl = newCodeUrl;
+


It might be elegant to delegate to a separate command to accomplish this.

I'll check if I can use WriteTextFileCommand for this

I adjusted WriteTextFileCommand to fit this case and used it in this command

lukemelia · 2026-01-22T16:12:50Z

packages/runtime-common/ai/prompt.ts

+          content = [content, switchSubmodeInstruction]
+            .filter(Boolean)
+            .join('\n\n');
+        }


I'm not enthusiastic about having command-specific code in the ai prompt generation. Is this necessary?

My intent was to not add more text to the skills prompt since this should be a rare case. I checked and we can achieve this by adding a line to the development skill and drop this new logic in the ai bot

Ai bot logic removed, and I added some extra instructions in the development skill: cardstack/boxel-skills@2719575#r2721123671

packages/host/app/commands/write-text-file.ts

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packages/host/tests/integration/commands/switch-submode-test.gts

…h-ai-it-will-sometimes

lukemelia · 2026-01-26T15:02:51Z

packages/base/command.gts

  @field overwrite = contains(BooleanField);
+  @field useNonConflictingFilename = contains(BooleanField);


Perhaps it should be an error in the command if the caller passes both overwrite and useNonConflictingFilename as true?

👍 good idea

Add createFile param to switch submode command

9f1f875

jurgenwerk added 2 commits January 20, 2026 12:26

Merge branch 'main' into cs-9640-when-trying-to-create-a-new-card-wit…

74f3808

…h-ai-it-will-sometimes

Test + cleanup

2cbf92e

jurgenwerk force-pushed the cs-9640-when-trying-to-create-a-new-card-with-ai-it-will-sometimes branch from 76b1b4d to 2cbf92e Compare January 20, 2026 12:13

jurgenwerk requested a review from Copilot January 20, 2026 12:42

Copilot started reviewing on behalf of jurgenwerk January 20, 2026 12:42 View session

Copilot AI reviewed Jan 20, 2026

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packages/host/app/utils/file-name.ts Outdated Show resolved Hide resolved

packages/host/app/commands/switch-submode.ts Outdated Show resolved Hide resolved

jurgenwerk and others added 3 commits January 20, 2026 13:56

Simplify condition

500da65

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Throw an error when non-conflicting file name cannot be found

621a1dc

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Add test case

ad904dd

jurgenwerk marked this pull request as ready for review January 20, 2026 13:45

jurgenwerk requested a review from a team January 20, 2026 13:57

jurgenwerk changed the title ~~Add createFile param to switch submode command~~ Add createFile param to the switch submode command Jan 20, 2026

Merge branch 'main' into cs-9640-when-trying-to-create-a-new-card-wit…

21d54b8

…h-ai-it-will-sometimes

lukemelia reviewed Jan 22, 2026

View reviewed changes

jurgenwerk added 3 commits January 23, 2026 11:00

Not needed - moved this to the development skill

adcf1ba

Use WriteTextFileCommand in SwitchSubmodeCommand

1c4dd8b

Not needed anymore

16c7b3b

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Fix import order

6a64735

cursor bot reviewed Jan 23, 2026

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packages/host/app/commands/write-text-file.ts Show resolved Hide resolved

Fix case when empty file reuse doesn't write non-empty content

8bee425

jurgenwerk force-pushed the cs-9640-when-trying-to-create-a-new-card-with-ai-it-will-sometimes branch from 5084d41 to 8bee425 Compare January 23, 2026 14:39

Simplify

74bbc64

cursor bot reviewed Jan 26, 2026

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packages/host/tests/integration/commands/switch-submode-test.gts Outdated Show resolved Hide resolved

jurgenwerk added 2 commits January 26, 2026 09:44

Fix expected assertion count

cbf61e2

Merge branch 'main' into cs-9640-when-trying-to-create-a-new-card-wit…

bf454b5

…h-ai-it-will-sometimes

jurgenwerk requested a review from lukemelia January 26, 2026 09:47

lukemelia approved these changes Jan 26, 2026

View reviewed changes

Don't allow using both overwrite and useNonConflictingFilename

2920284

jurgenwerk merged commit c646a7c into main Jan 26, 2026
94 of 98 checks passed

		@field overwrite = contains(BooleanField);
		@field useNonConflictingFilename = contains(BooleanField);

Add createFile param to the switch submode command #3867

Add createFile param to the switch submode command #3867

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