Claude Code v2.0.56

What: Claude Code now warns you before you hit rate limits by monitoring your usage percentage in real-time, rather than only alerting when limits are reached.

How it works:

• 5-hour limits: Warning at 90% usage when 72% through the window
• Weekly limits: Graduated warnings at 25%, 50%, and 75% based on time progression
• Warnings now show exact usage: "75% of weekly limit used · resets in 2 days"

Details:

• New function BX5() at line 341284 reads anthropic-ratelimit-unified-*-utilization headers
• New threshold configuration eW5 at line 341262 defines warning triggers
• Five-hour limit warnings were completely disabled in v2.0.55 (returned null), now active
• Evidence: BX5() at line 341284, AX5() at line 341260, tW5() at line 341242

What: View or edit your current session's plan file directly from the command line.

How to use:

# View the current plan
/plan

# Open plan file in your editor
/plan open

Details:

• Shows plan content, file path, and editor name
• Displays "No plan found for current session" if no plan exists
• Evidence: Command definition Xj3 at line 495530-495591

What: Plan mode instructions are now sent to Claude every 5 turns instead of every turn, reducing token usage while maintaining plan awareness.

Details:

• New constant gX5.TURNS_BETWEEN_ATTACHMENTS = 5 at line 343717
• New function cX5() at line 343068 counts turns since last plan attachment
• Reduces repetitive context by ~80% in long planning sessions
• Evidence: pX5() at line 343087, cX5() at line 343068

What: The transcript now shows "Plan file referenced (/path/to/plan)" when plan mode is active, providing visibility into which plan file is being used.

Details:

• New function o10() at line 342568 creates the attachment
• Helpful when resuming sessions to see which plan is active
• Evidence: o10() at line 342568, rendering at line 468780

What: Enterprise admins can now allow or deny MCP servers by their exact command invocation, not just by name.

How to use:

{
  "allowedMcpServers": [
    { "serverName": "weather" },
    { "serverCommand": ["npx", "-y", "@company/approved-server"] }
  ]
}

Details:

• Each entry must have EITHER serverName OR serverCommand, not both
• Command matching requires exact array equality (all arguments must match)
• Backward compatible - name-based matching still works
• New functions TzA() at line 509000 and KiA() at line 509003 for type checking
• Evidence: O8B() at line 185472, Tv1() at line 185485, schema at line 509164-509190

What: SDK users can now customize system prompts and define agents programmatically during initialization.

How to use:

await sdk.init({
  systemPrompt: "You are a specialized assistant...",
  appendSystemPrompt: "Additional instructions...",
  agents: {
    "coder": {
      "description": "Coding specialist",
      "prompt": "You are an expert programmer...",
      "tools": ["bash", "write"],
      "model": "claude-opus-4"
    }
  }
})

Details:

• systemPrompt - Override the default system prompt
• appendSystemPrompt - Add to the default system prompt
• agents - Define agents as JSON without file-based configuration
• Evidence: $v3() at line 521902, new parameter handling at lines 521915-521920

What: New tool that allows terminating background shell processes by ID.

Details:

• Variable KI1 = "KillShell" at line 480255
• Complements the existing background shell functionality
• Evidence: KI1 at line 480255

What: Failed telemetry events are now queued, batched, and retried with exponential backoff instead of being lost.

Details:

• Events saved to ~/.claude/telemetry/1p_failed_events.{session}.{batch}.json
• Maximum 8192 queued events, batch size of 200
• Exponential backoff: 500ms → 2s → 4.5s → 8s → 30s (capped)
• Events persist across CLI restarts and are retried on next session
• Default timeout increased from 5s to 10s
• Evidence: Class zm1 at line 234387, queueFailedEvents() at line 234542, retryPreviousBatches() at line 234448

What: LSP diagnostics are now limited to 10 per file and 30 total, sorted by severity to preserve the most important issues.

Details:

• Constants D21 = 10 (per file) and RG2 = 30 (total) at line 341029
• Severity sorting via TG2() at line 340898: Errors → Warnings → Info → Hints
• Cross-turn deduplication prevents same diagnostic from appearing repeatedly
• Diagnostics cleared when file is modified via H21() at line 341024
• Evidence: SG2() at line 340948, rIA tracking map at line 341032

What: The plan mode system prompt has been restructured for clearer phases and better guidance.

Details:

• Simplified from 5 phases with detailed multi-agent instructions
• Default behavior now launches Plan agents for most tasks
• Clearer guidance on when to skip agents (trivial tasks only)
• Evidence: Pk3() at line 510641

What: Authentication caches are now automatically cleared when settings change, preventing stale credential issues.

Details:

• New code in mg() state handler at line 519860
• Calls npA() and apA() to clear auth caches on settings changes
• Evidence: mg() at line 519860, lines 519882-519887

What: Better handling of heredocs in bash commands, including comment detection and nested heredoc filtering.

Details:

• New function cS3() at line 507823 detects if position is inside a comment
• Unique session-based heredoc markers via uS3() at line 507807
• Filters out nested heredocs that appear inside other heredocs
• Evidence: pF0() at line 507843, cS3() at line 507823

What: The file path checking for protected files now includes the plan file path.

Details:

• Function NX5() (was TF5) at line 342574 now checks against yU(Q) (plan file path)
• Prevents accidental modifications to the active plan file outside plan mode
• Evidence: NX5() at line 342574

What: Rate limit warning notifications now properly track state to avoid duplicate notifications.

Details:

• New state tracking in VZ9() at line 477794
• Uses useState for isUsingOverage tracking
• Prevents "Now using extra usage" notification from appearing multiple times
• Evidence: VZ9() at line 477794

What: Fixed escape key behavior in transcript mode when operating in subagent context.

Details:

• Function B89() (was O49) at line 474049 now checks ic context
• Prevents unnecessary jJ() calls when in subagent mode
• Evidence: B89() at line 474049