New in v19.0.0 - ✨ MCP, Diff, Editor Context ... too many

[olimorris]

Dear All,

#2692 sees CodeCompanion bump to v19.0.0. This is a milestone release and the biggest one yet. It's also the second major release in two months with breaking changes - something I do not take lightly.

Important

Keep your plugins pinned to v18.0.0 to avoid these breaking changes.

Breaking Changes

CodeCompanion includes an upgrade guide in the documentation to better enable you to upgrade. The key notes are:

• The Tools API has been refactored meaning any custom tooling you have will need to be refactored. However, there's an "upgrade tools" prompt in the action palette that you can use to help you on this
• The Super Diff has been removed
• Support for other diff providers has been removed
• The next_edit_suggestion and list_code_usages tools have been removed - feel free to add them to your own config to use them
• The full_stack_dev is now called agent
• The Claude Code ACP adapter requires claude-agent-acp to be installed after Zed renamed it
• The diff config and keymaps have moved

What's New

MCP (#2549)

Huge shout out to @cairijun for which sees CodeCompanion add support for MCP via stdio. This has been a joy to use over the past month and a huge addition to the plugin. Be sure to checkout the documentation.

New Diff (#2600)

I'd been inspired by Zed's Diff and sought to improve CodeCompanion's default. Word level highlighting, navigating by hunks, keymap display in virtual text. It's much improved and I hope you like it.

Agent mode (#2786)

The #{full_stack_dev} has been renamed to #{agent}. It includes a curated system prompt and adds the ability for groups of tools to overwrite a chat buffer's system prompt.

Editor Context Improvements (#2719 | #2780)

Previously, CodeCompanion had "variables" in the plugin to denote context that related to Neovim. This was a direct name mapping to Copilot Chat. Alas, it wasn't explicit enough and caused confusion. So I've renamed them editor context and added additional items such as #{buffers} to share all buffers, #{quickfix} (which replaces the slash command), #{diagnostics} (shares the buffer and LSP diagnostics, replacing #{lsp}.

Per-Project Configuration (#2778)

Depending on the project I'm working on, I may want a different chat default. Or, I may want to have specific default_tools or default_servers (in the case of MCP). CodeCompanion can now look to load additional config depending on what you've specified in the config.

Prompt Library (#2725)

A prompt library item can now specify default tools and MCP servers.

Customizable Prefixes (#2710)

A fantastic suggestion by @meijieru to enable prefixes to be customized. That is, allow users to remap #, / and @ symbols in the chat buffer to better suit their workflow

Closing Thoughts

There's a ton of things that I have forgotten / didn't have time to include in this announcement. This PR was in the works for two months and I don't enjoy saving up this many features to then deploy in a single release. Alas, this warranted some significant testing time.

I also don't foresee any breaking changes in the near future either so expect v19.0.0 to remain throughout most of the year where I have a ton of feature ideas to implement.

Finally, I've added an "AI Usage" section to PR templates. As I'm sure most of you are aware, the amount of PRs that open-source projects are facing is increasing, seemingly driven by AI tools. I'm all in favour of this. CodeCompanion is a small enough project that I can stay on top of everything but I ask users to respect this and be honest. I've had huge enjoyment working with Opus 4.6 throughout a lot of v19.0.0 and the CodeCompanion codebase is well structured and documented enough that it can be hugely productive.

Thanks and hope you enjoy this release!

[harrisoncramer]

This is awesome, thank you for your hard work on this tool -- super excited to try all these new features.

[Or1g3n]

I think I will be buying you at least 20 coffees because I use CodeCompanion every day and couldn't imagine a workflow without. Thanks a lot for all the work you put into this project!