v2.1.259 Claude Code Release Notes

Sep 2, 2026

Claude's Analysisby Sonnet 5

Major stability pass fixes concurrent-session ~/.claude.json corruption, --resume failures; adds managedMcpServers plus a breaking allowedMcpServers scope change.

Changes

Total Changes (vs Average)

2.7×

Version Type

Patch

Release Focus

Bug Fixes

Day Since Prior Release

Release # This Month

#3 of 9

Bug Fix Ratio

70%

Post-Release Edits

—

Change Category

Ecosystem Impact

MCP appears in 6 of the last 10 releases, and this one adds org-wide managed MCP servers alongside a breaking change to how allowedMcpServers scopes them.

Key Themes

8Session & data integrity hardening|6MCP gets a new lever and a breaking change|3Headless and automation tooling expands|5Rendering and workflow UX polish

May Help If You've Noticed

Running several sessions at once reset your workspace trust or lost MCP settings

Added5 changes

•Added managedMcpServers managed setting: organizations can provide HTTP/SSE MCP servers to every user (same entry shape as .mcp.json); entries that name a command to run are skipped
•Added --permission-prompts none for unattended headless hosts: anything that would prompt is denied automatically while the active permission mode (including auto mode) keeps deciding
•Added recognition of glab mr create/merge/close/reopen/note/update so GitLab merge requests show as MR !N in the collapsed tool summary and refresh the footer MR badge
•Added --json to claude plugin validate for a machine-readable validation report
•[VSCode] Added an Active quick filter and a status filter menu (Needs input, Working, Completed) to the session list sidebar

Improved5 changes

•Improved terminal resize and first-render performance for long responses by reusing text measurements
•Improved /workflows agent detail: JSON outcomes are pretty-printed with syntax colors and real line breaks, and long outcomes fold behind an expand toggle
•Improved headless/SDK session start: the first turn begins up to 50 ms sooner when MCP servers finish connecting
•Improved /install-github-app to explain it is GitHub-only and point to the GitLab CI/CD docs when run inside a GitLab repository
•Improved nested background subagent results to be saved in the parent subagent's transcript, so resumed subagents keep them and shared transcripts show the delivery

Fixed26 changes

•Fixed concurrent sessions silently reverting each other's ~/.claude.json changes — workspace trust no longer resets and MCP/project state is no longer lost when running many sessions at once
•Fixed a conversation whose thinking was rejected once being rejected again on every later turn
•Fixed Bash Read() deny rules not covering files given as option values (--ignore-revs-file=.env, -f.env, @file), git diff/git grep file operands, or cd DIR && cat FILE compounds; grep -r/cp -r over a directory holding a denied file now asks
•Fixed the prompt cache being invalidated when the OAuth token refreshed in sessions with telemetry disabled
•Fixed fullscreen mode showing a blank conversation after a long turn with hundreds of tool calls
•Fixed auto mode running a turn on a model it doesn't support when a command or skill's frontmatter model: named one; the turn now keeps the session model
•Fixed CLAUDE_CODE_MAX_CONTEXT_TOKENS being ignored for Vertex-style model IDs (@YYYYMMDD suffix) of model versions Claude Code doesn't recognize
•Fixed the live output preview of a running shell command hiding its newest lines when an earlier line wrapped
•Fixed a background GitHub connection check that ran on every launch for claude.ai users; the result is now remembered across launches
•Fixed --resume failing (and --continue opening an empty conversation) when a saved session contains an attachment entry with no payload
•Fixed frontmatter model: on custom commands and skills being ignored in interactive sessions
•Fixed Artifact publishing failing once with an "unexpected parameter note" error in conversations continued from an older version
•Fixed managed forceRemoteSettingsRefresh being ignored at startup when a policy helper configured by MDM or the managed settings file had already run
•Fixed worktree isolation refusing hook-created worktrees on machines where git rev-parse fails with a message other than "not a git repository"
•Fixed OpenTelemetry metrics and events from cloud sessions missing the user.email, organization.id, and user.account_uuid attributes
•Fixed MCP servers that disconnect while their tools are being listed at startup showing as connected with no tools instead of reporting the error
•Fixed the file edit permission dialog sometimes showing a changed line cut short with no indication
•Fixed repository detection dropping a known repo identity after a transient git probe failure
•Fixed managed settings silently going unenforced when the managed-settings file, a drop-in, the MDM plist, or the HKLM value cannot be parsed: Claude Code now refuses to start and names the source
•Fixed Stop not actually stopping background agents and workflows in remote-control sessions: killed tasks now stay visible and re-stoppable until their processes exit
•Fixed resuming a workflow run while its previous stopped run was still exiting, which could run duplicate copies of its agents
•Fixed marketplace repo URLs on github.com with a trailing slash or dangling ?/# producing an unusable .git clone URL
•Fixed blocking Stop hooks causing the turn after a block to lose the model's reasoning from that turn and, on some models, miss the prompt cache
•Fixed remote (claude.ai) sessions taking 60 seconds to start a turn after a browser-hosted MCP server's page had gone away
•Fixed worktree-isolated sessions refusing common Bash loops, xargs pipelines and launcher-wrapped commands that cannot reach the main checkout
•Fixed remote and scheduled sessions doing nothing after a connector-tool permission prompt was approved while the session was paused

Changed1 change

•Changed allowedMcpServers to govern only servers users add: a literal managed-mcp.json server your allowlist used to filter out now loads on upgrade; use deniedMcpServers to keep it off

Added5 changes

•Added managedMcpServers managed setting: organizations can provide HTTP/SSE MCP servers to every user (same entry shape as .mcp.json); entries that name a command to run are skipped

•Added --permission-prompts none for unattended headless hosts: anything that would prompt is denied automatically while the active permission mode (including auto mode) keeps deciding

•Added recognition of glab mr create/merge/close/reopen/note/update so GitLab merge requests show as MR !N in the collapsed tool summary and refresh the footer MR badge

•Added --json to claude plugin validate for a machine-readable validation report

•[VSCode] Added an Active quick filter and a status filter menu (Needs input, Working, Completed) to the session list sidebar

Improved5 changes

•Improved terminal resize and first-render performance for long responses by reusing text measurements

•Improved /workflows agent detail: JSON outcomes are pretty-printed with syntax colors and real line breaks, and long outcomes fold behind an expand toggle

•Improved headless/SDK session start: the first turn begins up to 50 ms sooner when MCP servers finish connecting

•Improved /install-github-app to explain it is GitHub-only and point to the GitLab CI/CD docs when run inside a GitLab repository

•Improved nested background subagent results to be saved in the parent subagent's transcript, so resumed subagents keep them and shared transcripts show the delivery

Fixed26 changes

•Fixed concurrent sessions silently reverting each other's ~/.claude.json changes — workspace trust no longer resets and MCP/project state is no longer lost when running many sessions at once

•Fixed a conversation whose thinking was rejected once being rejected again on every later turn

•Fixed Bash Read() deny rules not covering files given as option values (--ignore-revs-file=.env, -f.env, @file), git diff/git grep file operands, or cd DIR && cat FILE compounds; grep -r/cp -r over a directory holding a denied file now asks

•Fixed the prompt cache being invalidated when the OAuth token refreshed in sessions with telemetry disabled

•Fixed fullscreen mode showing a blank conversation after a long turn with hundreds of tool calls

•Fixed auto mode running a turn on a model it doesn't support when a command or skill's frontmatter model: named one; the turn now keeps the session model

•Fixed CLAUDE_CODE_MAX_CONTEXT_TOKENS being ignored for Vertex-style model IDs (@YYYYMMDD suffix) of model versions Claude Code doesn't recognize

•Fixed the live output preview of a running shell command hiding its newest lines when an earlier line wrapped

•Fixed a background GitHub connection check that ran on every launch for claude.ai users; the result is now remembered across launches

•Fixed --resume failing (and --continue opening an empty conversation) when a saved session contains an attachment entry with no payload

•Fixed frontmatter model: on custom commands and skills being ignored in interactive sessions

•Fixed Artifact publishing failing once with an "unexpected parameter note" error in conversations continued from an older version

•Fixed managed forceRemoteSettingsRefresh being ignored at startup when a policy helper configured by MDM or the managed settings file had already run

•Fixed worktree isolation refusing hook-created worktrees on machines where git rev-parse fails with a message other than "not a git repository"

•Fixed OpenTelemetry metrics and events from cloud sessions missing the user.email, organization.id, and user.account_uuid attributes

•Fixed MCP servers that disconnect while their tools are being listed at startup showing as connected with no tools instead of reporting the error

•Fixed the file edit permission dialog sometimes showing a changed line cut short with no indication

•Fixed repository detection dropping a known repo identity after a transient git probe failure

•Fixed managed settings silently going unenforced when the managed-settings file, a drop-in, the MDM plist, or the HKLM value cannot be parsed: Claude Code now refuses to start and names the source

•Fixed Stop not actually stopping background agents and workflows in remote-control sessions: killed tasks now stay visible and re-stoppable until their processes exit

•Fixed resuming a workflow run while its previous stopped run was still exiting, which could run duplicate copies of its agents

•Fixed marketplace repo URLs on github.com with a trailing slash or dangling ?/# producing an unusable .git clone URL

•Fixed blocking Stop hooks causing the turn after a block to lose the model's reasoning from that turn and, on some models, miss the prompt cache

•Fixed remote (claude.ai) sessions taking 60 seconds to start a turn after a browser-hosted MCP server's page had gone away

•Fixed worktree-isolated sessions refusing common Bash loops, xargs pipelines and launcher-wrapped commands that cannot reach the main checkout

•Fixed remote and scheduled sessions doing nothing after a connector-tool permission prompt was approved while the session was paused

v2.1.259 Claude Code Release Notes

Changes in Claude Code v2.1.259

Added5 changes

Improved5 changes

Fixed26 changes

Changed1 change

v2.1.259 Claude Code Release Notes

Changes in Claude Code v2.1.259

Added5 changes

Improved5 changes

Fixed26 changes

Changed1 change