Agent skill

Upgrade Browser

Upgrade browser versions (Chrome or Firefox) in the Flutter Web Engine and/or Framework tests.

BSD-3-ClauseAuto-check passedMobile

Install Upgrade Browser

skills CLI

$ npx skills add flutter/flutter --skill upgrade-browser -a claude-code

Project install by default; add -g for ~/.claude/skills/.

GitHub CLI

$ gh skill install flutter/flutter upgrade-browser --agent claude-code

Project scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).

Manual copy

$ git clone --depth 1 https://github.com/flutter/flutter.git skills-src && mkdir -p .claude/skills && cp -r skills-src/.agents/skills/upgrade-browser .claude/skills/upgrade-browser && rm -rf skills-src

Use ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.

Claude Code skills documentation · loads skills from .claude/skills/

Paste into Claude Code

Install the "upgrade-browser" agent skill from https://github.com/flutter/flutter/tree/master/.agents/skills/upgrade-browser into .claude/skills/upgrade-browser/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "upgrade-browser", then confirm the skill loads.

Claude Code copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

$skill-installer

$skill-installer install https://github.com/flutter/flutter/tree/master/.agents/skills/upgrade-browser

Type this inside Codex. $skill-installer <name> installs a curated skill from openai/skills. The installer writes to $CODEX_HOME/skills (default ~/.codex/skills). Restart Codex if the skill does not show up.

skills CLI

$ npx skills add flutter/flutter --skill upgrade-browser -a codex

Project install goes to .agents/skills/; add -g for ~/.codex/skills/.

GitHub CLI

$ gh skill install flutter/flutter upgrade-browser --agent codex

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/flutter/flutter.git skills-src && mkdir -p .agents/skills && cp -r skills-src/.agents/skills/upgrade-browser .agents/skills/upgrade-browser && rm -rf skills-src

Use ~/.agents/skills/ instead of .agents/skills for a personal install.

Codex skills documentation · loads skills from .agents/skills/

Paste into Codex

Install the "upgrade-browser" agent skill from https://github.com/flutter/flutter/tree/master/.agents/skills/upgrade-browser into .agents/skills/upgrade-browser/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "upgrade-browser", then confirm the skill loads.

Codex copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

skills CLI

$ npx skills add flutter/flutter --skill upgrade-browser -a cursor

Project install goes to .agents/skills/; add -g for ~/.cursor/skills/.

GitHub CLI

$ gh skill install flutter/flutter upgrade-browser --agent cursor

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/flutter/flutter.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/.agents/skills/upgrade-browser .cursor/skills/upgrade-browser && rm -rf skills-src

Use ~/.cursor/skills/ instead of .cursor/skills for a personal install.

Cursor skills documentation · loads skills from .cursor/skills/, .agents/skills/, .claude/skills/, .codex/skills/

Paste into Cursor

Install the "upgrade-browser" agent skill from https://github.com/flutter/flutter/tree/master/.agents/skills/upgrade-browser into .cursor/skills/upgrade-browser/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "upgrade-browser", then confirm the skill loads.

Cursor copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

gemini skills install

$ gemini skills install https://github.com/flutter/flutter.git --path .agents/skills/upgrade-browser

--scope user (default) or --scope workspace; --path is the subfolder of the repo that holds the skill; --consent skips the security confirmation prompt.

skills CLI

$ npx skills add flutter/flutter --skill upgrade-browser -a gemini-cli

Project install goes to .agents/skills/; add -g for ~/.gemini/skills/.

GitHub CLI

$ gh skill install flutter/flutter upgrade-browser --agent gemini-cli

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/flutter/flutter.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/.agents/skills/upgrade-browser .gemini/skills/upgrade-browser && rm -rf skills-src

Use ~/.gemini/skills/ instead of .gemini/skills for a personal install, then run /skills reload.

Gemini CLI skills documentation · loads skills from .gemini/skills/, .agents/skills/

Paste into Gemini CLI

Install the "upgrade-browser" agent skill from https://github.com/flutter/flutter/tree/master/.agents/skills/upgrade-browser into .gemini/skills/upgrade-browser/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "upgrade-browser", then confirm the skill loads.

Gemini CLI copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

GitHub CLI

$ gh skill install flutter/flutter upgrade-browser

Installs for Copilot at project scope by default; add --scope user for a personal install. Preview a skill first with gh skill preview. Needs GitHub CLI 2.90.0 or later (public preview).

skills CLI

$ npx skills add flutter/flutter --skill upgrade-browser -a github-copilot

Project install goes to .agents/skills/; add -g for ~/.copilot/skills/.

Manual copy

$ git clone --depth 1 https://github.com/flutter/flutter.git skills-src && mkdir -p .github/skills && cp -r skills-src/.agents/skills/upgrade-browser .github/skills/upgrade-browser && rm -rf skills-src

Use ~/.copilot/skills/ instead of .github/skills for a personal install. Commit .github/skills so cloud agent and code review can use it.

GitHub Copilot skills documentation · loads skills from .github/skills/, .claude/skills/, .agents/skills/

Paste into GitHub Copilot

Install the "upgrade-browser" agent skill from https://github.com/flutter/flutter/tree/master/.agents/skills/upgrade-browser into .github/skills/upgrade-browser/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "upgrade-browser", then confirm the skill loads.

GitHub Copilot copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

skills CLI

$ npx skills add flutter/flutter --skill upgrade-browser -a opencode

OpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.

GitHub CLI

$ gh skill install flutter/flutter upgrade-browser --agent opencode

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/flutter/flutter.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/.agents/skills/upgrade-browser .opencode/skills/upgrade-browser && rm -rf skills-src

Use ~/.config/opencode/skills/ instead of .opencode/skills for a personal install.

OpenCode skills documentation · loads skills from .opencode/skills/, .claude/skills/, .agents/skills/

Paste into OpenCode

Install the "upgrade-browser" agent skill from https://github.com/flutter/flutter/tree/master/.agents/skills/upgrade-browser into .opencode/skills/upgrade-browser/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "upgrade-browser", then confirm the skill loads.

OpenCode copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

Facts

Skill name: upgrade-browser
GitHub stars: 179k
Token cost: ~1.1k tokens
SKILL.md length: 473 words
Files: 2 (incl. scripts)
Skills in repo: 14
Repo updated: Oct 8, 2026
First seen: Oct 8, 2026
Licence: BSD-3-Clause

At a glance

Upgrade browser versions (Chrome or Firefox) in the Flutter Web Engine and/or Framework tests.

Works in 5 steps: Identify and Verify the New Version → Update Local Files → CI Config Sync → …
Firefox to a newer version
SKILL.md covers Workflow and Examples
Runs Dart scripts from its folder; calls dart

What it does

Upgrade Browser is an agent skill from flutter/flutter. Upgrade browser versions (Chrome or Firefox) in the Flutter Web Engine and/or Framework tests. Use when asked to roll or upgrade Chrome or Firefox to a newer version.

Its SKILL.md is about 1.1k tokens, which your agent loads only when the skill is triggered. The skill folder holds 2 other files, including scripts.

It sits in Mobile, covering Cross-platform mobile apps. It works with Flutter, Linux and Dart. The repository describes itself as: Flutter makes it easy and fast to build beautiful apps for mobile and beyond. The licence is BSD-3-Clause.

When your agent uses it

Firefox to a newer version
Tasks that involve Cross-platform mobile apps

Example prompts

“/upgrade-browser”

Workflow steps

5 steps, taken from the step headings in SKILL.md.

Identify and Verify the New Version
Update Local Files
CI Config Sync
Local Verification
CIPD Upload (Package Roller)

What it can do on your machine

Read from SKILL.md and the folder at commit 8679894. It shows what the files ask for, not the result of running them.

Tool permissions
Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.
From allowed-tools in the SKILL.md frontmatter.
Runs code
Ships 1 file in scripts/ (Dart), which the agent can run.
Shell commands in SKILL.md call:
- dart
From the folder's file list and the shell code blocks in SKILL.md.
Network
No URLs in SKILL.md.
From URLs in SKILL.md, links to its own repository left out.
Credentials
Names no API keys, tokens, secrets or passwords.
From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Upgrade Browser loads about 1.1k tokens when it runs. Until then it costs about 46 tokens; SKILL.md has 473 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it: ~46
When it runs · the whole SKILL.md, loaded when a task matches: ~1.1k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Auto-check passed

The automated check found no risky patterns in SKILL.md.

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); the scripts in this folder are not scanned.

SKILL.md

The full file from flutter/flutter at commit 8679894, republished under its BSD-3-Clause licence (© flutter). 473 words, ~1,077 tokens.

Download SKILL.mdSave it as .claude/skills/upgrade-browser/SKILL.md (or your agent's skills folder). This skill also uses 1 other file; get the full folder from GitHub.

name: upgrade-browser
description: Upgrade browser versions (Chrome or Firefox) in the Flutter Web Engine and/or Framework tests. Use when asked to roll or upgrade Chrome or Firefox to a newer version.

Upgrade Browser

This skill automates the process of upgrading Chrome and Firefox versions in the Flutter Web Engine and the Framework tests.

Workflow

1. Identify and Verify the New Version

Before updating any files, find and verify the existence of the version you want to use.

To find the latest stable version:

bash

dart scripts/fetch_versions.dart latest <chrome|firefox>

To verify a specific version exists:
bash
```
dart scripts/fetch_versions.dart verify <chrome|firefox> <version>
```
This command will return true or false.

Verification Rules:

Enforced by default: If the command returns false, do not proceed.
Optional if requested: If the user explicitly asks to skip verification (e.g., "Upgrade to version X without verification"), you may skip this step.
Failed verification: If verification fails but the user confirms they want to proceed anyway, you may continue.

2. Update Local Files

The user may request to upgrade one or both locations. They may also use different versions for each location.

Flutter Web Engine (`engine/src/flutter/lib/web_ui/dev/package_lock.yaml`)

Update the version field for chrome or firefox.

yaml

chrome:
  version: 'NEW_VERSION'

firefox:
  version: 'NEW_VERSION'

Framework Tests (`.ci.yaml`)

Update all occurrences of chrome_and_driver with the new version.

yaml

- {"dependency": "chrome_and_driver", "version": "version:NEW_VERSION"}

Use replace with allow_multiple: true to ensure all instances are updated. Note: Currently, only Chrome is managed this way in .ci.yaml.

3. CI Config Sync

After updating the browser versions, synchronize the CI configurations. This step updates engine/src/flutter/ci/builders/linux_web_engine_test.json.

Only run this once. To verify if it needs to run, check the modification time of the file:

bash

ls -l engine/src/flutter/ci/builders/linux_web_engine_test.json

From engine/src/flutter/lib/web_ui, run:

bash

dev/felt generate-builder-json

Validation: Confirm the file engine/src/flutter/ci/builders/linux_web_engine_test.json has a new timestamp after the command finishes.

4. Local Verification

Before uploading to CIPD, run tests locally to ensure no regressions. From engine/src/flutter/lib/web_ui, run:

bash

dev/felt test

Note: You can use --browser <chrome|firefox> to limit the scope.

Show full SKILL.md (212 more words)Show less

5. CIPD Upload (Package Roller)

This is the final step as it uploads binaries to CIPD and requires special, temporary permissions.

Ask the user if they have the necessary CIPD permissions (contact #hackers-infra on Discord if unsure).
If confirmed, from engine/src/flutter/lib/web_ui, run:
bash
```
dart dev/package_roller.dart
```
Note: Use --dry-run if the user wants to test first.

Examples

User: "Upgrade Chrome and Firefox to the latest stable versions everywhere."
Agent:
1. Runs dart scripts/fetch_versions.dart latest to get the latest versions.
2. Updates engine/src/flutter/lib/web_ui/dev/package_lock.yaml and .ci.yaml.
3. Runs dev/felt generate-builder-json to sync CI configs.
4. Suggests running local tests.
5. Finally, asks about CIPD permissions.
User: "Roll Chrome to version 135.0.0.0 everywhere. Skip verification."
Agent:
1. Skips dart scripts/fetch_versions.dart verify because the user requested it.
2. Updates package_lock.yaml and .ci.yaml directly with 135.0.0.0.
3. Follows the rest of the workflow (Sync, Test, CIPD).
User: "Update Firefox in the web engine to 130.0."
Agent:
1. Verifies version 130.0 for Firefox using dart scripts/fetch_versions.dart verify firefox 130.0.
2. If verification fails, informs the user: "I was unable to verify Firefox version 130.0 through Mozilla's official release history. Are you sure this is the correct version number?"
3. If user confirms or verification succeeds, updates package_lock.yaml.
4. Follows the rest of the workflow (Sync, Test, CIPD).

Files

SKILL.md and 1 other file (scripts) in .agents/skills/upgrade-browser of flutter/flutter.

SKILL.md
scripts/fetch_versions.dart

Open the folder on GitHubat commit 8679894

Compare with similar skills

Upgrade Browser next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.

Upgrade Browser compared with similar skills
Skill	Stars	Used in	Tokens	Auto-check	Licence	Repo updated
Upgrade Browser this skillflutter/flutter	179k	—	~1.1k	Automated safety check: Pass	BSD-3-Clause	today
flutter_soloud Setupalnitak/flutter_soloud	424	—	~3.6k	Automated safety check: Notes	MIT	yesterday
Gui Testlibnativeapi/nativeapi	161	—	~3.5k	Automated safety check: Pass	MIT	today
Fkit SetupJoker-x-dev/FlutterKit	127	—	~720	Automated safety check: Pass	MIT	2 mo ago
Native Desktop UI TestingFNOSP/FlyNarwhal	495	—	~2.4k	Automated safety check: Pass	AGPL-3.0	yesterday
Flutter Pub ReleaseMixinNetwork/flutter-plugins	512	—	~1.3k	Automated safety check: Pass	MIT	1 mo ago

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Questions about Upgrade Browser

What does Upgrade Browser do?

Upgrade browser versions (Chrome or Firefox) in the Flutter Web Engine and/or Framework tests. Upgrade Browser is an agent skill from flutter/flutter. Upgrade browser versions (Chrome or Firefox) in the Flutter Web Engine and/or Framework tests.

When should I use Upgrade Browser?

Upgrade Browser fits situations like: firefox to a newer version; tasks that involve Cross-platform mobile apps.

How do I install Upgrade Browser in Claude Code?

Run `npx skills add flutter/flutter --skill upgrade-browser -a claude-code`. Or copy the skill folder (.agents/skills/upgrade-browser in flutter/flutter) into .claude/skills/upgrade-browser in your project. Claude Code loads it when a task matches its description.

How do I install Upgrade Browser in Codex?

Run `npx skills add flutter/flutter --skill upgrade-browser -a codex`. Or copy the skill folder (.agents/skills/upgrade-browser in flutter/flutter) into .agents/skills/upgrade-browser in your project. Codex loads it when a task matches its description.

Can I use Upgrade Browser in Cursor, Gemini CLI or GitHub Copilot?

Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add flutter/flutter --skill upgrade-browser -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/upgrade-browser, .gemini/skills/upgrade-browser, .github/skills/upgrade-browser and .opencode/skills/upgrade-browser in your project.

What does Upgrade Browser need to run?

Going by SKILL.md and its folder, Upgrade Browser needs Dart for the scripts in its folder and the command-line tools its instructions call (dart).

Does Upgrade Browser access the network?

SKILL.md contains no URLs. Any network use would come from the scripts or tools the agent runs. This is read from the text; nothing was executed.

Is Upgrade Browser safe to install?

Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. The check reads SKILL.md only: the scripts in the folder are not scanned, so read them before running anything.

What licence does Upgrade Browser use?

Upgrade Browser is published under the BSD-3-Clause licence (the repository's licence). It allows redistribution, so the full SKILL.md is shown on this page.

How many tokens does Upgrade Browser use?

About 1.1k tokens (SKILL.md is roughly 4.3k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full.

What are the alternatives to Upgrade Browser?

Skills that share tags, products or a category with Upgrade Browser: flutter_soloud Setup (alnitak/flutter_soloud, 424 stars), Gui Test (libnativeapi/nativeapi, 161 stars), Fkit Setup (Joker-x-dev/FlutterKit, 127 stars) and Native Desktop UI Testing (FNOSP/FlyNarwhal, 495 stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.

Who maintains Upgrade Browser?

flutter (a GitHub organization) maintains it in flutter/flutter, which has 179,369 GitHub stars. The repository holds 14 skills in this directory. The repository was last updated on October 8, 2026.

Source: flutter/flutter on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.

Install Upgrade Browser

Facts

At a glance

What it does

When your agent uses it

Example prompts

Workflow steps

What it can do on your machine

Tool permissions

Runs code

Network

Credentials

Context cost

Safety

SKILL.md

Upgrade Browser

Workflow

1. Identify and Verify the New Version

2. Update Local Files

Flutter Web Engine (engine/src/flutter/lib/web_ui/dev/package_lock.yaml)

Framework Tests (.ci.yaml)

3. CI Config Sync

4. Local Verification

5. CIPD Upload (Package Roller)

Examples

Files

Compare with similar skills

Similar skills

More from flutter/flutter

Related

Questions about Upgrade Browser

Flutter Web Engine (`engine/src/flutter/lib/web_ui/dev/package_lock.yaml`)

Framework Tests (`.ci.yaml`)