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AI-Generated Commit Messages

SmartGit versions 25 and later offer optional AI-generated assistance when adding commit messages.

This feature can enhance productivity and accuracy when creating new commits by enabling capabilities such as:

  • Evaluating the diff for your next commit and creating an AI-generated commit message
  • Rewording or correcting typographical errors in a user-entered commit message
  • Ensuring that a commit message accurately reflects the changes in the commit
  • Enforcing commit message standards defined by your team or organization

All AI-based features are disabled by default, ensuring no data is shared without user consent. Users must opt-in and configure these services.

A key objective of this initiative is to empower users with full control over how large language models (LLMs) interact with their version control workflows. You have the freedom to make informed decisions about which parts of your codebase can be used with specific LLM or AI services that you trust and have access to.

For first time users, please consult these quick-start tutorials on how to use SmartGit’s AI features:

SmartGit’s AI features do not operate through an assistant like ChatGPT. Instead, SmartGit interacts directly with AI models via their APIs. When using a custom or commercial Large Language Model (LLM), an account with an API integration key will be required.

If you wish to configure SmartGit to use different or custom LLMs, or need to customize LLM prompting and other options, please consult the AI Integration reference documentation.

Warning

SmartGit will submit the contents of the staged diff as part of a prompt to the configured Large Language Model (LLM) to obtain AI-generated output.

It is recommended that you evaluate the level of trust and confidentiality appropriate for your repository before enabling SmartGit’s AI features.

This consideration may depend on whether the LLM is self-hosted or cloud-hosted, the security and privacy guarantees provided by the LLM service, and whether your repository is private or open-source.

As a result, SmartGit’s AI commenting feature is disabled by default.

Enabling AI Commenting Features

SmartGit’s AI features are disabled by default and can be enabled the first time the AI button is clicked. The following options are shown:

  • Use GitHub models globally - Adds configuration to use the default LLM in your global git.config file, applying to all repositories on your computer.

  • Use GitHub models for this repository - Adds configuration to use the default LLM in the current repository’s git/config file only.

  • Configure manually - Opens the AI Configuration page with instructions on how to add ai-llm and ai-commit-message sections to your Git configuration files.

  • Disable AI configuration (selected by default) - Disables SmartGit AI integration.

Selecting between AI Models

By default SmartGit uses the public GitHub Large Language Model (LLM) once AI commenting is enabled.

However, if additional AI models are configured, you can use the down arrow between the AI button and the Hamburger Menu (☰) in the Commit View to select the LLM that SmartGit will use for AI features.

Commit Message Generation

SmartGit utilizes AI-powered Large Language Models (LLMs) to generate or analyze commit messages based on your working tree modifications or staged changes.

This involves transmitting the complete git diff (or git diff --cached) to an AI service.

Once enabled, an AI button with a drop-down menu appears in the Commit View.

This menu lists all configured AI services and indicates the currently active ones.

Clicking the button or selecting a different AI service sends the Git diff to the chosen provider, which generates a commit message and streams it back to SmartGit.

Staged and Untracked Files

As with any commit staging, generally, only staged files are included in the Git diff submitted to the AI. However, the diff also depends on which Main Window is being used and the staging preferences:

Options

By default, the AI-generated commit message is inserted at the current cursor location in the commit message of the Commit View. Interaction between the existing commit message, any manual modifications, and the AI-generated message depends on several options:

On Manual Intervention

  • Stop - Stops commit message generation upon any manual change (e.g., typing text or moving the cursor).
  • Continue in Background - Allows generation to continue and stores the message in a buffer, instead of displaying it immediately. The AI button will blink green to indicate that buffered content is available.

Commit Message Line Wrapping

By default, the commit message description is wrapped at 72 characters. Wrapping can be disabled using the Low-level property ai.commitMessageGeneration.wrapDescription.

Commit Message Rewording

SmartGit can optionally reword messages for commits that have not yet been pushed (see hamburger menu); the mechanism is the same as for the Commit Message Generation, and the same configuration is utilized.

There are two different operational modes here:

  • Rewording @ai messages: For commits containing @ai in their message, the @ai marker will be replaced by an AI-generated message.
  • Rewording WIP messages: For commits with the exact message as WIP (or wip, case-sensitive), the message will be replaced by an AI-generated message and prefixed with WIP:, i.e. WIP: <ai generated message>.

Low-level properties ai.commitMessageRewording.* can be used to customize this process.

Notes

  • You can reset SmartGit’s AI configuration by removing all ai-llm and ai-commit-message sections from your Git configuration files (global, personal and/or repository).
  • @ai and WIP placeholders are only substituted when you add a commit - not interactively and not by clicking the AI button.
  • The WIP token must be the only text in the commit message - no additional text or whitespace.
  • When @ai is immediately followed by < (e.g. @ai<some input), the marker is trimmed before the commit message is passed to the prompt (i.e. only some input will remain). The generated message will completely replace the original @ai-prefixed message, not just the @ai token.
  • If SmartGit does not substitute the @ai or WIP tokens, re-enable token substitution by clicking the drop down arrow next to the AI icon and the Hamburger menu above the Commit View, and selecting the Reword ‘@ai’ and ‘WIP’ commits options.
  • Use the low-level property ai.commitMessageRewording.aiRegex to change the @ai token.
  • Use the low-level property ai.commitMessageRewording.wipRegex to to modify the WIP token and ai.commitMessageRewording.wipPrefix setting to change the prefix used.

Errors and Troubleshooting

If errors occur during the interaction with the AI, SmartGit will show that an error has occurred, with details about the error.

Common errors include:

  • 404 / Resource Not Found - Indicates that the url setting in the [ai-llm] git config section may be incorrect, or possibly the LLM API is unavailable.

    Check the LLM provider’s API instructions and verify the integration config setting.

    Some APIs require a prefix, e.g., openai/gpt-4.1 would be an example model configuration for github.ai.

  • The Git diff is too large - the diff exceeds the maxDiffSize setting in [ai-commit-message].

    Increase the maxDiffSize setting if needed. However, large diffs can be challenging to describe in a concise commit message, whether AI or Human generated.

  • **AI generation of the commit message failed - Request body too large for ** - The LLM's token limit was exceeded. Free/public LLMs may allow ~8,000 tokens; commercial LLMs may allow 100,000+.

Tips + Notes

  • Align the maxDiffSize setting with typical commit sizes for your team and within the token limits of your chosen LLM provider.

  • Code has a higher token density than natural language, depending on the programming language.

  • Tools like tiktoken can help estimate token counts per line or file.
  • Although commercial providers generally bill for usage as a function of input and output token counts, unless your team makes very high frequency and/or commits with very large diffs, using SmartGit to assist with commit messages is unlikely to incur more than a few US$ per month.