Fx v0.0.9

fx can now use a frontier model for steering, then delegate to cheaper models to implement. Subagents keep running while you steer, can have different models and reasoning levels, and take feedback mid-task. We're accomplishing this without any new commands or concepts, just chat with fx.

Breaking Changes

• For simplicity, ! in the composer is just prompt text now. It no longer starts a terminal session. Commands go through the agent and the usual approval flow.

New Features

• Subagents can use their own model and reasoning effort. Use GPT-6, Astra, or Fable 5.1 to steer, then delegate implementation to Kimi K3.
• You can send feedback to a running named subagent without interrupting its current tool. The final result still comes back to the parent conversation.
• New conversations get a short title from the first prompt. Turn generated session titles off in /settings.
• Press ctrl+p while writing to open the model picker. Your draft and attached images stay where they are.
• ACP clients can set reasoning effort on supported models. They can also replay earlier tool calls as structured events.
• New runnable libfx examples for Node.js, browsers, Next.js, and Nuxt.

Improvements

• fx -c and fx --continue now resume the workspace’s remembered conversation without a full session scan.
• Compaction now shows in the activity row. If you send a message while it's running, it waits, then runs with the compacted context.
• Assistant Markdown now renders nested emphasis, links, code spans, lists, fenced code blocks, and entities the way GitHub does.
• @~, @., and @.. open the home directory, workspace, and parent directory. No trailing slash needed. File suggestions also stay put while you browse and refine them.
• Escape needs a second press within one second to interrupt active work. ctrl+c clears a non-empty composer first; with an empty composer, it interrupts active work, then exits fx on the next press.

Bug Fixes

• Running subagents keep going if a file lookup fails. Follow-up messages also don't leave named subagents stuck.
• AI Gateway now applies the reasoning effort you selected on chat requests. Prompts with images no longer fail on the v4 endpoint.
• Long replies no longer shuffle transcript rows or overwrite the last character on a full-width terminal line.
• MCP OAuth now works with servers that support PKCE but leave none out of their metadata, including Slack MCP.

Security

• Auto mode now checks which terminal session it's sending input to, including after a resume.
• Auto mode no longer reuses an earlier safety-review decision when judging a later action.
• Auto mode no longer raises false cautions when you use a credential with the service it's for, or with a local test process.