2.1.75 untested · changelog-derived

Claude Code 2.1.75

**1M context window for Opus 4.6** — Max, Team, and Enterprise plans now have Opus 4.6 with 1M context by default, removing the friction of opt-in usage tier selection and enabling agents to reason over larger corpora without breaking the working-memory budget.

5 new primitives 3 workflow recipes 14 fixes

New primitives

/colorcommand

Set a prompt-bar color for your session

Added `/color` command for all users to set a prompt-bar color for your session
Opus 4.6 1M context (Max/Team/Enterprise)capability

Expand default reasoning window from the standard context to 1M tokens

Added 1M context window for Opus 4.6 by default for Max, Team, and Enterprise plans (previously required extra usage)
Session name display on prompt barsetting

Show the current session name on the prompt bar when using `/rename`

Added session name display on the prompt bar when using `/rename`
Memory last-modified timestampscapability

Track and display when memory files were last edited, helping Claude reason about freshness

Added last-modified timestamps to memory files, helping Claude reason about which memories are fresh vs. stale
Hook source display in permission promptscapability

Show which system component (settings/plugin/skill) is requesting permission

Added hook source display (settings/plugin/skill) in permission prompts when a hook requires confirmation

Workflow recipes

Multi-artifact reasoning over large specification sets
Opus 4.6 1M context window + Memory last-modified timestamps

The 1M context window removes the working-memory ceiling that previously forced agents to chunk specification ingestion across turns or delegate to sub-agents. Combined with memory freshness tracking, an agent can now load a full specification corpus (dependency graphs, API docs, schema definitions, request/response examples), timestamp-gate stale vs. fresh docs in-context, and produce high-fidelity architectural analysis or code generation in a single reasoning pass.

An agent receives a 50-100 MB specification repository (OpenAPI/GraphQL schemas, design docs, reference implementations, example payloads). With 1M context, the agent loads all related documents at once, uses memory timestamps to prioritize fresh specs over outdated ones, cross-references without intermediate chunking, and synthesizes a comprehensive implementation plan or code migration guide. This eliminates the previous pattern of "load spec A, digest, ask follow-up for spec B, re-ingest context."

Automated permission auditing with hook source transparency
Hook source display in permission prompts + improved async hook messaging

Operators running unattended agents now see exactly which system layer (settings/plugin/skill) is requesting resources. This transparency unlocks automated permission auditing: an agent can log permission patterns, detect unexpected hook sources, and flag configurations that need review without losing context about where the permission originated.

A scheduled agent runs periodically to ingest framework logs and permission-prompt transcripts, categorizing hook requests by source layer and flagging anomalies (e.g., a skill requesting file I/O at unexpected times). The operator gets a weekly audit report with recommendations to tighten .claude/settings.json rules. Hook source visibility is the foundational signal; without it, the operator would have to instrument the logs separately.

Session continuity for long-running investigation chains
Session name display on prompt bar + Memory last-modified timestamps + Fixed /resume for session names

Long investigations (incident response, architecture review, competitor analysis) now have visual continuity. The prompt bar shows the session name, memory freshness is transparent, and /resume preserves session identity across forks. An agent can fork for a risky hypothesis, resume the parent if the fork fails, and the operator always sees which investigation thread they're in.

An operator starts a "2026-Q2-security-audit" session. An agent forks to "—hypothesis-supply-chain-risk" and investigates. If the risk is unfounded, the agent calls code /resume to return to the parent investigation with full session name and memory freshness visible on the prompt bar. The operator can see at a glance whether they're in the main audit or a hypothesis branch, and which memories are current vs. stale (important for time-sensitive findings).

Agentic relevance

The 1M context window expansion for Opus 4.6 is the highest-impact primitive for agents: it removes the working-memory constraint for multi-document reasoning, specification ingestion, and context-rich delegation. Session naming + memory freshness tracking improve agent continuity and reasoning quality. Hook source visibility strengthens permission transparency for automated workflows.

Hardening & fixes (14)

  • Fixed voice mode not activating correctly on fresh installs without toggling `/voice` twice
  • Fixed the Claude Code header not updating the displayed model name after switching models with `/model` or Option+P
  • Fixed session crash when an attachment message computation returns undefined values
  • Fixed Bash tool mangling `!` in piped commands (e.g., `jq 'select(.x != .y)'` now works correctly)
  • Fixed managed-disabled plugins showing up in the `/plugin` Installed tab — plugins force-disabled by your organization are now hidden
  • Fixed token estimation over-counting for thinking and `tool_use` blocks, preventing premature context compaction
  • Fixed corrupted marketplace config path handling
  • Fixed `/resume` losing session names after resuming a forked or continued session
  • Fixed Esc not closing the `/status` dialog after visiting the Config tab
  • Fixed input handling when accepting or rejecting a plan
  • Fixed footer hint in agent teams showing "↓ to expand" instead of the correct "shift + ↓ to expand"
  • Improved startup performance on macOS non-MDM machines by skipping unnecessary subprocess spawns
  • Suppressed async hook completion messages by default (visible with `--verbose` or transcript mode)
  • Breaking change: Removed deprecated Windows managed settings fallback at `C:\ProgramData\ClaudeCode\managed-settings.json` — use `C:\Program Files\ClaudeCode\managed-settings.json`

Raw changelog

## 2.1.75

- Added 1M context window for Opus 4.6 by default for Max, Team, and Enterprise plans (previously required extra usage)
- Added `/color` command for all users to set a prompt-bar color for your session
- Added session name display on the prompt bar when using `/rename`
- Added last-modified timestamps to memory files, helping Claude reason about which memories are fresh vs. stale
- Added hook source display (settings/plugin/skill) in permission prompts when a hook requires confirmation
- Fixed voice mode not activating correctly on fresh installs without toggling `/voice` twice
- Fixed the Claude Code header not updating the displayed model name after switching models with `/model` or Option+P
- Fixed session crash when an attachment message computation returns undefined values
- Fixed Bash tool mangling `!` in piped commands (e.g., `jq 'select(.x != .y)'` now works correctly)
- Fixed managed-disabled plugins showing up in the `/plugin` Installed tab — plugins force-disabled by your organization are now hidden
- Fixed token estimation over-counting for thinking and `tool_use` blocks, preventing premature context compaction
- Fixed corrupted marketplace config path handling
- Fixed `/resume` losing session names after resuming a forked or continued session
- Fixed Esc not closing the `/status` dialog after visiting the Config tab
- Fixed input handling when accepting or rejecting a plan
- Fixed footer hint in agent teams showing "↓ to expand" instead of the correct "shift + ↓ to expand"
- Improved startup performance on macOS non-MDM machines by skipping unnecessary subprocess spawns
- Suppressed async hook completion messages by default (visible with `--verbose` or transcript mode)
- Breaking change: Removed deprecated Windows managed settings fallback at `C:\ProgramData\ClaudeCode\managed-settings.json` — use `C:\Program Files\ClaudeCode\managed-settings.json`
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