--- collection: coding-agents collection_name: Coding Agents week_start: 2026-09-28 title: Strong models land across the coding agents release_count: 16 generated: 2026-10-05 canonical: https://releases.sh/collections/coding-agents/digest/2026-09-28 --- # Strong models land across the coding agents OpenAI's GPT-6.1 Sol became the default engine for Codex, Claude Sonnet 5.5 arrived with a 1M context window, and Devin pushed deeper into Jira and cross-device workflows — while a heavy week of fixes hardened every agent's terminal and sandbox. ### New default models The week's biggest shift was under the hood of OpenAI's Codex. [GPT-6.1 Sol launched in Codex and ChatGPT Work](https://developers.openai.com/codex/changelog/#codex-2026-09-29-gpt-61-sol) as a near-Astra model aimed at complex, long-running work across code, apps, and documents at lower cost, and [it became the default in the bundled catalog](https://developers.openai.com/codex/changelog/#github-release-399499631) — plus the Amazon Bedrock Mantle and Runtime catalogs. Anthropic's Claude Code countered with [Claude Sonnet 5.5 as its default Sonnet model](https://code.claude.com/docs/en/changelog#2-1-284), bringing a 1M context window and $2/$10 per Mtok pricing, with the same release repairing damaged response streams and letting MCP tool calls in resumed sessions wait for a still-connecting server. ### Devin moves into the tools around it Devin's week was about meeting developers where they already work. It is now [a native agent inside Jira](https://docs.devin.ai/release-notes/overview#september-30-2026), starting sessions when a work item is assigned or mentioned, with automations able to run a preflight script after each trigger before the agent starts. That release also made messages sent right before a connection drop survive on the server, sent Devin Review findings on PRs back to the originating session for auto-fix, and introduced Devin Mono, a new monospace typeface for code blocks and terminals, alongside a read-only live shell preview. Separately, Devin made [view preferences follow you across browsers and devices](https://docs.devin.ai/release-notes/overview#september-25-2026) — search mode, changed-files tree layout, and sidebar filters now sync — and added Option+J/Option+K session navigation, child sessions that carry a parent summary, and pipeline log support for Bitbucket Data Center and Azure DevOps. ### Tightening the sandboxes and the terminal Claude Code shipped six updates this week, and the throughline was safety. [Sandbox deny-rule bypasses got closed off](https://code.claude.com/docs/en/changelog#2-1-289) so a mod's approval can no longer override deny or ask rules on nested parts of compound commands, Bash deny rules hold under auto-allow even when a variable assignment precedes the command, and a terminal freeze on pathological code blocks is gone. An earlier update [caught a dangerous rm slipping through unpropmaned in a bash -c script](https://code.claude.com/docs/en/changelog#2-1-288) and prompted re-authentication when an MCP server requests more OAuth scope. Credential leaks were a theme too: [secret-redaction gaps closed across MCP errors, percent-encoded tokens, and URL passwords](https://code.claude.com/docs/en/changelog#2-1-286), while `--resume` and `--continue` no longer lose turns after a batch of parallel tool calls. Claude Code also [opened the desktop app straight from the CLI](https://code.claude.com/docs/en/changelog#2-1-285) with `--desktop`, added an `allowedProviders` managed setting, and [introduced Claude Mods with a "You should know" side agent](https://code.claude.com/docs/en/changelog#2-1-287) that watches for things you or Claude might miss. Codex's CLI churn was quieter but practical: [instant interrupt lets new input steer a response in progress](https://developers.openai.com/codex/changelog/#github-release-398926954), with prompt suggestions removed and Windows console flashing suppressed for background processes. Terminal settings now persist correctly across sessions, and [queued messages resume after reconnection](https://developers.openai.com/codex/changelog/#github-release-401312540) without duplicate sends. ### Smaller fixes, same direction Grok Build [let custom agents be chosen directly with spawn_subagent](https://x.ai/build/changelog#1-0-45) and added MCP token files that are re-read on every request so rotating credentials stay fresh. A follow-up made [permission rules with relative paths apply through symlinked working directories](https://x.ai/build/changelog#1-0-46) and fixed video cards getting stuck extracting posters without ffmpeg. ## Releases covered ### Anthropic - [Claude Code v2.1.284 adds Claude Sonnet 5.5 as default with 1M context](https://code.claude.com/docs/en/changelog#2-1-284) - [Claude Code v2.1.289 fixes sandbox deny-rule bypasses and terminal freezes](https://code.claude.com/docs/en/changelog#2-1-289) - [Claude Code v2.1.288 fixes dangerous rm bypass and MCP scope re-auth](https://code.claude.com/docs/en/changelog#2-1-288) - [Claude Code v2.1.286 fixes session-resume data loss and credential secret leaks](https://code.claude.com/docs/en/changelog#2-1-286) - [Claude Code 2.1.285 adds --desktop flag and provider restrictions](https://code.claude.com/docs/en/changelog#2-1-285) - [Claude Code v2.1.287 adds Claude Mods and "You should know" side-agent plugin](https://code.claude.com/docs/en/changelog#2-1-287) ### Cognition - [Devin adds native Jira agent and preflight automation checks](https://docs.devin.ai/release-notes/overview#september-30-2026) - [Devin adds cross-device view sync, keyboard navigation, and interactive HTML reports](https://docs.devin.ai/release-notes/overview#september-25-2026) ### OpenAI - [OpenAI launches GPT-6.1 Sol in Codex and ChatGPT Work](https://developers.openai.com/codex/changelog/#codex-2026-09-29-gpt-61-sol) - [Codex 0.159.1 makes GPT-6.1 Sol the default model](https://developers.openai.com/codex/changelog/#github-release-399499631) - [Codex CLI 0.159.0 removes prompt suggestions and adds instant interrupt](https://developers.openai.com/codex/changelog/#github-release-398926954) - [Codex CLI 0.160.0 fixes terminal settings persistence and Windows sandbox](https://developers.openai.com/codex/changelog/#github-release-401312540) ### xAI - [Grok Build 1.0.45 adds custom agent selection and MCP token file support](https://x.ai/build/changelog#1-0-45) - [Grok Build 1.0.46 fixes symlinked permission paths and video card playback](https://x.ai/build/changelog#1-0-46)