Claude Code appends session URLs to all commits and PRs by default

The GitHub issue reports that attribution.commit defaults to enabled in .claude/settings.json without discovery paths. Users encounter the appended URL only after git history is written. A one-time onboarding prompt or first-commit toggle is proposed to make the behavior explicit rather than hidden.

No public benchmark or telemetry release from Anthropic quantifies the fraction of sessions that retain the default. Related patterns appear in earlier Anthropic tool releases where attribution trailers such as Co-Authored-By were added without user controls. Remote and cloud environments further reduce reliability of post-hoc git hooks that attempt to strip the line.

Operationally the change increases commit noise for teams and open-source maintainers while creating discoverability debt for the attribution setting. If the proposed opt-in path is shipped, adoption can be measured by the rate at which the setting remains false after first commit. Absent that change, downstream tooling will continue to develop workarounds.

Anthropic has not published a changelog entry or issue response as of the reported date.