Claude Code 2.1.299 changes file mentions and idle context handling
Anthropic published Claude Code 2.1.299 on October 14, 2026. The notes describe idle compaction for terminal conversations of at least 200,000 tokens after roughly 54 minutes, before an hourlong cache expires. This aims to avoid processing the entire history again when work resumes.
The notes also list threshold and disable controls requiring 2.1.290 or later. Listing them here does not establish that every part of idle compaction first shipped in 2.1.299.
A shorter history has a cost of its own
Anthropic’s usage documentation explains why a short question can consume substantial usage in an old session. Each request carries the conversation, including accumulated tool results. Cached input can reduce the cost of reading that history, but a request after the cache expires processes it again.
The cache lifetime is not universal. The documentation describes an hour for subscription usage, five minutes by default for an API key or cloud provider, and a change to five minutes when drawing on usage credits unless the lifetime is explicitly selected. The hourlong scenario in the release should not be assumed to describe every account or gateway.
Compaction itself reads the history it summarizes. It therefore consumes usage rather than providing a free reset. The /usage display separates cache misses from expected rebuilds following compaction and reports whether the main conversation cache is warm. That gives readers a way to inspect their own session rather than assume a fixed percentage saving.
The context guide adds a second tradeoff. Claude Code clears older tool outputs and summarizes when needed, but detailed instructions from early in the conversation can disappear. Persistent requirements belong in CLAUDE.md. A Compact Instructions section can identify information to retain, while /context shows what is occupying the window.
For a debugging session, the useful checkpoint is the evidence behind the current theory. Before leaving a large investigation idle, record the failing test, affected files and unresolved questions in the project’s working notes. After returning, check that the summary still supports the next proposed edit. This is a suggested workflow, not a test result from this release.
File mentions can pass a path instead of contents
The environment variable reference confirms that CLAUDE_CODE_DISABLE_FILE_MENTIONS requires 2.1.299 or later. Setting it to 1 prevents expansion of file and directory mentions. Claude receives their paths and an instruction to read them through its file tools. The variable is ignored in project and local settings.
That makes configuration location important. The reference distinguishes a variable set for a terminal session from one saved in user settings. It also warns that precedence differs between variables and dedicated settings, so a project file is not a universal place to control every behavior.
This changes how a mentioned file enters the conversation. It should not be described as a privacy barrier that makes the file inaccessible. A review can still require reading it. The practical comparison is whether loading the complete material immediately helps the task or whether a focused read will provide enough evidence.
Fixes matter separately from new controls
Anthropic also reports fixes involving permission checks, stopped mods and repeated tool execution. One addresses duplicate approved calls when new messages arrive during restart recovery in cloud or headless sessions. Another unloads remotely disabled mods between turns. These are vendor reported repairs, not independently reproduced findings. ByteForward’s earlier 2.1.296 coverage explains that release’s separate controls for delegated work.
Check the installed build before comparing behavior
According to the installation guide, native installations download updates in the background and apply them when Claude Code next starts. Package manager installations generally require their own update process. The stable channel typically trails by about a week, while latest receives new releases. A release appearing on GitHub does not mean every installation already runs it.
Use claude doctor to inspect the most recent update attempt. For a native installation, claude update checks immediately. Teams should retain their deployment policy rather than change channels casually to match an article. Package availability can lag an update notification.
A useful rollout check is a small repository task with a known expected result. Record the installed version, context behavior and resulting changes, then compare with the previous build under the same conditions. Check whether work survives a break and whether repeated actions remain absent. ByteForward has not benchmarked this release or measured savings from idle compaction.
Illustrative coding workspace photographed by Bayu Syaits on Unsplash. Cropped from the original under the Unsplash License. This is not a screenshot of Claude Code 2.1.299.
