Claude Code v2.0.31

What: Optional profiling system to measure Claude Code's startup performance and memory usage across initialization phases.

How to use:

# Enable startup profiling
CLAUDE_CODE_PROFILE_STARTUP=1 claude

# The profiling report will automatically display after startup showing:
# - Time elapsed at each checkpoint (absolute and delta)
# - Memory usage (RSS and heap) at each checkpoint
# - Total startup time

Details:

• Tracks 30+ checkpoints throughout the startup sequence
• Records both timing (via Node.js perf_hooks) and memory metrics
• Zero overhead when disabled (default)
• Useful for diagnosing slow startup issues or investigating performance regressions
• Evidence: o5() at line 3881, RB9() at line 3891, B80() at line 3919, profiler initialization in aqA at line 3926

What: Privacy-preserving telemetry that tracks file operations (read, write, edit) using hashed identifiers.

How it works:

• File paths are hashed (SHA256, first 16 characters) for anonymization
• File content is hashed (SHA256) to detect duplicate operations
• Operation type and tool name are recorded
• Data sent via existing telemetry infrastructure

Details:

• Automatically enabled when telemetry is active
• Only metadata is recorded - actual file paths and content remain private
• Helps Anthropic understand common file operation patterns
• Evidence: sM() function at line 249864, hash functions Nd8() at line 249858 and Ld8() at line 249861

What: Support for the new web-search-2025-03-05 beta API.

Details:

• Automatically enabled for Vertex AI platform with Claude 4.x models
• Provides access to updated web search capabilities
• Part of Anthropic's beta features system
• Evidence: ErB = "web-search-2025-03-05" at line 203723, AT8() function at line 203732

What: Significantly improved security validation for sed commands to prevent dangerous operations while allowing safe read-only usage.

How it works: The validation now uses a comprehensive whitelist approach with multiple layers:

1. Pre-parsing flag detection - Blocks dangerous flag combinations like -ew, -we before parsing
2. Whitelist validation - Only allows two safe patterns:

• Print-only operations with -n flag (e.g., sed -n '1,10p' file.txt)
• Simple substitutions with safe flags (e.g., sed 's/old/new/' file.txt)

1. Comprehensive blacklist - Blocks 15+ dangerous patterns including:

• Write commands (w, W)
• Execute commands (e, E)
• Non-ASCII characters and escape sequences
• Command chaining with semicolons in certain contexts
• Braces, negation operators, and other advanced features

Details:

• Builds upon existing sed validation from v2.0.30 (function hoB at line 209135)
• Adds four new validation helpers: Aj8() at line 209202, Bj8() at line 209245, Qj8() at line 209254, Zj8() at line 209384
• New validation function JtB() at line 209288 replaces hoB
• Dangerous flag combination detection in Gj8() at line 209345
• Prevents file modification and command execution while allowing safe text processing
• Evidence: Comparison of hoB() at line 209135 in v2.0.30 vs JtB() at line 209288 in v2.0.31

What: Streamlined diff patch rendering with cleaner code and fewer configuration options.

Changes:

• Removed skipUnchanged and hideLineNumbers parameters from diff rendering
• Eliminated conditional dimmed color variants (diffAddedWordDimmed, diffRemovedWordDimmed)
• Simplified component interface from 7 parameters to 5
• Removed hidden parameter from line number component calls

Details:

• Function signature changed from hB6(A, B, Q, I, G, Z, Y) to $Q6(A, B, Q, I, G)
• More consistent visual rendering across different diff contexts
• Evidence: hB6() at line 288996 in v2.0.30 vs $Q6() at line 289176 in v2.0.31; word diff function fB6() at line 288906 in v2.0.30 vs wQ6() at line 289088 in v2.0.31

What: Added profiling checkpoints around settings initialization.

Details:

• Tracks time spent loading settings from various sources
• Helps identify slow configuration loading
• Evidence: o5("eagerLoadSettings_start") at line 485096, o5("eagerLoadSettings_end") at line 485107 in function Bo5() at line 485095

What: Added profiling checkpoints before and after CLI argument parsing.

Details:

• Helps identify overhead from command-line option processing
• Part of the overall startup profiling infrastructure
• Evidence: o5("cli_before_main_import") at line 486806, o5("cli_after_main_import") at line 486808 in function Wo5() at line 486798

What: Fixed shell command quoting logic to correctly handle file descriptor redirects.

Details:

• File descriptor redirects like 2> or 2>> are no longer incorrectly quoted
• Prevents errors when redirecting stderr or other file descriptors
• Evidence: Function ET8() at line 204583 adds check for \d+>>? pattern, replacing bR8() at line 204525 in v2.0.30

What: Fixed settings cleanup when removing the last hook from a configuration source.

Details:

• Ensures hooks object is properly removed when empty
• Prevents empty configuration objects from persisting
• Evidence: Function rV2() at line 414417 adds proper cleanup logic at lines 414433-414435, improving upon qV2() at line 414128 in v2.0.30

What: Consolidated and reorganized various module imports.

Changes:

• Replaced import Ae from "stream" with import { PassThrough as Lr5 } from "stream" at line 482338
• Replaced import e51 from "node:child_process" with import { execSync as U6Q, spawn as Qd8 } from "node:child_process" at line 249174
• Added import { cwd as hR0 } from "node:process" at line 70725
• Added import { homedir as br5 } from "node:os" at line 484007
• Added import { createHash as pB6, randomBytes as lB6 } from "crypto" at line 286520
• Removed redundant import BP9 from "node:os" and import il2 from "node:process"

Details:

• More explicit imports improve tree-shaking and code clarity
• Reduces namespace pollution from default imports

What: Updated native color diff module loading with better error handling.

Details:

• Added async function GVQ() at line 289328 for loading the Rust-based ColorDiff module
• Improved fallback behavior when native module unavailable
• Better logging for debugging color diff issues
• Evidence: Function GVQ() at line 289328, initialization in uy1 at line 289318

What: Various minor component and utility function additions.

Details:

• Added BVQ component at line 289014 for diff patch rendering
• Added utility functions: Vc() at line 446305, Qp5() at line 460873, xM2() at line 429780
• Added helper functions for tool management: Gu2() at line 456056, Ve1() at line 456053, Iu2() at line 456048

Note: This changelog focuses on user-visible changes and significant internal improvements. Version 2.0.31 includes additional internal refactoring and code organization improvements not detailed here.