Overview
- X published an expanded For You repository on GitHub under the Apache v2 license that exposes the platform’s multi-stage ranking pipeline and much of its model configuration, a release the company pushed public on Thursday.
- The company began rolling out an “Under the Hood” pilot that allows eligible accounts to download JSON reports summarizing labels and aggregate signals applied to their posts and accounts over the past month.
- Developers can run parts of the released ranker outside X and submit pull requests to the public repo for X engineers to consider, though X will decide which external changes it accepts.
- X withheld some components from the public release — notably the Grok-based violation predictor — and left certain operational weights and config values redacted, which experts say limits full reproducibility and makes gaming-resistance the stated rationale for the omissions.
- The code details reveal how Phoenix weights engagement and penalties — for example a predicted share carries roughly 40 times the weight of a like while predicted reports and mutes carry very large negative weights — and the move responds to long-running concerns about hidden recommendation systems and growing regulator interest in algorithmic transparency.