Grok Build v1.0.39

Grok Build v1.0.39 was released on September 20, 2026.

Summary

Grok Build 1.0.39 makes subagents easier to use by removing the need to pick a type when spawning them, and fixes a frustrating issue where your image attachments would disappear during compaction. We've also improved how the system handles temporary files and made error messa...

Release Context

This was the 148th Grok Build release of 2026 tracked by Havoptic.
It shipped 1 day after Grok Build v1.0.38 (September 19, 2026).

Shipped around the same time

Within 3 days of this release, other AI coding tools also shipped:

GitHub Copilot CLI v1.0.88 (September 22, 2026)
OpenAI Codex CLI rust-v0.156.0 (September 22, 2026)
Claude Code v2.1.280 (September 22, 2026)
Antigravity CLI v1.2.8 (September 22, 2026)
GitHub Copilot CLI v1.0.87 (September 21, 2026)

Compare Grok Build: vs Claude Code · vs OpenAI Codex CLI · vs Cursor · vs Gemini CLI · vs Kiro CLI · vs GitHub Copilot CLI · vs Devin Desktop · vs Antigravity CLI

Release Notes

Grok Build 1.0.39

Subagents can always use the parent model, with that choice locked in when the session starts
Earlier image attachments survive multiple compactions
Subagent spawning no longer requires choosing a type
The agent keeps helper scripts, logs, and PR drafts in the system temp directory instead of the repository
Model effort menus pick up live effort levels, and config aliases inherit them
MCP tools that receive the wrong JSON shape are automatically fixed when the mismatch is unambiguous
Local worktree capture no longer refuses repositories that contain uninitialized submodules
Memory captures no longer include opaque model reasoning blobs
Idle timeouts show a clear message instead of raw internal text
Images attached to the last user prompt survive compaction
Custom agent profiles persist correctly across session resume and reload
Subagent labels appear as "Subagent" instead of "General" in transcripts and the tasks pane

View original release

Other Recent Grok Build Releases

v1.0.37 (September 18, 2026)
v1.0.36 (September 17, 2026)
v1.0.34 (September 16, 2026)
v1.0.35 (September 16, 2026)
v1.0.33 (September 15, 2026)

All Grok Build releases · All AI coding tool releases on Havoptic