Claude Code Version Tracker: Environment Variables, Feature Gates & Models#

Published on March 7, 2026

We analyze every Claude Code release to document undocumented environment variables, feature gates, and model IDs. This page tracks all versions we've covered.

Version History#

v2.1.70 — March 2026#

167 env vars (+3, -1) · 41 feature gates · 16 models

CCR v2 bridge, effort level toggle, delta MCP instructions.

v2.1.69 — March 2026#

165 env vars (+82) · 41 feature gates (+41) · 16 models (+16)

Plugin system, mTLS, agent teams, context compaction.

v2.1.19 — January 2025#

83 env vars · ~16 feature gates

First extraction. Agent swarms, Plan v2, debug flags.

What We Extract#

Each release goes through string extraction from the Claude Code npm package:

• Environment variables — undocumented configuration knobs not in official docs
• Statsig feature gates — A/B test flags that control unreleased features
• Model IDs — all models supported in the binary
• Architecture changes — new subsystems, removed features, renamed internals

Results are diffed against the previous version to surface what actually changed.

Related Guides#

• Getting Started with Claude Code — installation, setup, first task
• Claude Code vs Cursor — deep comparison for 2026
• Context Window Management — session strategies
• Productivity Tips — CLAUDE.md, permissions, custom commands
• Bulk Permissions Management — stop clicking Allow
• Debugging Claude Code — env vars for troubleshooting
• Settings Schema with Autocomplete — IntelliSense for settings.json
• Autonomous Task Workflow — /task command deep dive

FAQ#

How do you extract this data?

String extraction from the Claude Code npm package, diffed against previous versions. The process is described in the first extraction post.

Are these officially supported?

No. These are undocumented internals. They may change or disappear without notice.

How often do you update?

We cover every significant release shortly after publication to npm.