Claude-Code v2.1.108: Prompt Caching Controls & Recap

New Environment Variables for Prompt Caching

v2.1.108 adds two environment variables for controlling prompt cache time-to-live (TTL). ENABLE_PROMPT_CACHING_1H opts into 1-hour prompt cache TTL on API key, Bedrock, Vertex, and Foundry deployments. The previously used ENABLE_PROMPT_CACHING_1H_BEDROCK is deprecated but still honored. FORCE_PROMPT_CACHING_5M forces a 5-minute TTL. The release also adds a warning at startup when prompt caching is disabled via DISABLE_PROMPT_CACHING* environment variables.

Session Recap Feature

A new recap feature provides context when returning to a session. This is configurable in /config and manually invocable with /recap. Users with telemetry disabled can force this feature with CLAUDE_CODE_ENABLE_AWAY_SUMMARY.

Skill Tool Enhancements

The model can now discover and invoke built-in slash commands like /init, /review, and /security-review via the Skill tool. This enables more dynamic interaction patterns where the AI can suggest relevant commands based on context.

Command Improvements

/undo is now an alias for /rewind
/model now warns before switching models mid-conversation, since the next response re-reads the full history uncached
/resume picker defaults to sessions from the current directory; press Ctrl+A to show all projects

Error Message Improvements

Server rate limits are now distinguished from plan usage limits. 5xx/529 errors show a link to status.claude.com. Unknown slash commands suggest the closest match.

Performance and Memory Optimizations

Reduced memory footprint for file reads, edits, and syntax highlighting by loading language grammars on demand.

Interface Improvements

Added "verbose" indicator when viewing the detailed transcript (Ctrl+O). Fixed terminal escape codes appearing as garbage text in the prompt input after --teleport.

Bug Fixes

The release includes 16 bug fixes addressing issues ranging from paste functionality in /login prompts to session management problems:

Fixed paste not working in the /login code prompt (regression in 2.1.105)
Fixed subscribers who set DISABLE_TELEMETRY falling back to 5-minute prompt cache TTL instead of 1 hour
Fixed Agent tool prompting for permission in auto mode when the safety classifier's transcript exceeded its context window
Fixed Bash tool producing no output when CLAUDE_ENV_FILE (e.g. ~/.zprofile) ends with a # comment line
Fixed claude --resume <session-id> losing the session's custom name and color set via /rename
Fixed session titles showing placeholder example text when the first message is a short greeting
Fixed /feedback retry: pressing Enter to resubmit after a failure now works without first editing the description
Fixed --teleport and --resume <id> precondition errors (e.g. dirty git tree, session not found) exiting silently instead of showing the error message
Fixed Remote Control session titles set in the web UI being overwritten by auto-generated titles after the third message
Fixed --resume truncating sessions when the transcript contained a self-referencing message
Fixed transcript write failures (e.g., disk full) being silently dropped instead of being logged
Fixed diacritical marks (accents, umlauts, cedillas) being dropped from responses when the language setting is configured
Fixed policy-managed plugins never auto-updating when running from a different project than where they were first installed