v0.21.0-rc.1

New features

• Server-Sent Event prediction streams. HTTP prediction requests can now ask for Accept: text/event-stream to receive start, output, log, metric, and terminal completed events for predictors that explicitly opt in with @streaming / @cog.streaming. Reconnecting clients can replay retained in-flight prediction events with PUT /predictions/{id}. (#3019)

Improvements

• Experimental warning for cog weights. Every cog weights subcommand now prints a warning that the weights workflow is experimental and should not be relied on in production workflows yet. (#3025)
• Static schema parser target resolution. The static Python schema parser now uses run() as the primary prediction entry point while preserving legacy predict() fallback behavior, and resolves inherited and imported targets more consistently. (#3027)

Bug fixes

• cog doctor --fix now shows available remediation text. Findings without an auto-fix now display their remediation message instead of incorrectly saying no auto-fix is available. (#3031)
• Cog-managed weight uploads now send the correct layer media type. Weight layer uploads now propagate the Cog weight media type during registry finalization while preserving regular image-layer behavior. (#3033)
• Predictor validation now handles PEP 563 string annotations. Predictor files using from __future__ import annotations no longer reject valid setup() -> None methods or accept invalid run() -> None methods because None annotations were stored as strings. (#3034)