DesignFix checks a Java project against design rules written as XPath queries over the code's srcML representation, and uses an LLM to suggest a fix for each violation. You review every suggested fix in a VS Code diff and accept or reject it.
Getting started
Open a Java project folder that has ruleTable.json and tagTable.json at its root. DesignFix starts automatically in such folders and adds DesignFix to the status bar.
Run DesignFix: Set OpenAI API Key from the Command Palette. The key is kept in VS Code's secret storage on your machine.
Click DesignFix in the status bar, or run DesignFix: Open Dashboard. The dashboard opens in your browser and loads the project.
Under Violated Rules, pick a violation and click Fix.
Review the proposed change in the VS Code diff, then choose DesignFix: Accept Fix or DesignFix: Reject Fix in the editor title bar.
How it works
The extension converts each .java file in the workspace to srcML with the bundled srcML 0.9.5.
The dashboard, served by the extension on your machine, checks each rule in ruleTable.json and lists the violations, each paired with an example of the rule being followed elsewhere in the same project.
When you click Fix, the dashboard sends the violation and its context to the OpenAI API through the extension, which adds your key.
The extension shows the proposed edit as a diff. Nothing changes on disk until you accept it.
Requirements
Windows x64 for the bundled srcML. On macOS or Linux, install srcML 0.9.5 yourself (not 1.x, which changes the XML the rules depend on) and point the designfix.srcmlPath setting at it.
A trusted workspace. DesignFix does not run in Restricted Mode.
Commands
Command
What it does
DesignFix: Open Dashboard
Opens the dashboard in your browser (also the DesignFix status bar item).
DesignFix: Set OpenAI API Key
Stores your key in VS Code secret storage.
DesignFix: Clear OpenAI API Key
Removes the stored key.
DesignFix: Accept Fix / Reject Fix
Applies or discards the fix under review (editor title bar).
DesignFix: Mine Rules
Experimental. Suggests rules from your code (editor context menu in Java files). Needs Java and spmf.jar in the project root.
Settings
Setting
Default
Description
designfix.srcmlPath
empty
Path to a srcML 0.9.5 executable. Empty uses the bundled Windows srcML, or /usr/local/bin/srcml (macOS) and /usr/bin/srcml (Linux).
designfix.dashboard.port
0
Port for the local dashboard server. 0 picks a free port.
designfix.fixLogs.enabled
false
Save a record of each accepted fix (prompts, model responses, and the original and modified files) for research use.
designfix.fixLogs.directory
empty
Where to save fix records. Empty uses the extension's storage folder.
designfix.devSocket.enabled
false
Also accept a dashboard run from source (npm start) on port 8887.
Privacy and security
Nothing is sent to OpenAI until you click Fix. Each fix then makes two requests (model gpt-4o-2024-11-20). They contain the rule's description and XPath query, the full content of the file with the violation, a rule-following example from your project, and up to four related files from your project.
Your API key stays in VS Code's secret storage. The extension adds it to requests to api.openai.com; it is never sent to the browser.
The dashboard server listens on 127.0.0.1 only and answers only the dashboard's own page, so other computers and other websites cannot use it.
The dashboard loads nothing from third-party servers, and DesignFix collects no telemetry.
Accepted fixes are not recorded unless you turn on designfix.fixLogs.enabled.
MIT. The third-party components in this extension (srcML and its libraries, and the dashboard's packages) and their licenses are listed in THIRD_PARTY_NOTICES.md, included in the extension.
Developed by the DevX lab at George Mason University. DesignFix builds on ActiveDocumentation and RulePad.
