# Claude Code v2.1.75

> Claude Code v2.1.75, released 13 Mar 2026 (2026-03-13). 23 entries read out of the shipped bundle. Unofficial, and not affiliated with Anthropic.

Web version: https://changelogs.core-directive.com/v/2.1.75

This release introduces Opus 1M context as the default for first-party Opus users, adds a memory staleness system that warns when recalled memories may be outdated, redesigns the SendMessage tool for more intuitive agent-to-agent communication, and introduces plugin configurable options. Several quality-of-life improvements include concurrent session detection, an auto mode circuit breaker, and a new SSH `startDirectory` setting.

## Changes

### Opus 1M Context Window Default

**What**

First-party Opus users now default to a 1M token context window (5x larger), with automatic migration from the standard Opus setting.

**Details**

- Controlled by the `tengu_cobalt_compass` feature flag (gradual rollout)
- Users who had "opus" selected are automatically migrated to "opus[1m]"
- A merge notice is shown up to 6 times: "Opus now defaults to 1M context · 5x more room, same pricing"
- When Opus 1M is active, Opus no longer triggers "Billed as extra usage" — same pricing as before
- The model picker now offers an explicit "Opus (1M context)" entry labeled `[NEW]`

**Evidence**

Opus 1M migration and display (search for `"tengu_cobalt_compass"`, `"Opus now defaults to 1M context"`, `"tengu_opus_to_opus1m_migration"`)

- Flag `tengu_cobalt_compass`: On for this account, and not off by default (read for one account on one subscription tier against v2.1.75; this account: on, anonymous baseline: on, compiled default: no gate table built for this version) These values were read against a different version of Claude Code, so treat them as the nearest reading available instead of one taken on this release.

### Plugin Configurable Options

**What**

Plugins can now declare user-configurable options in their manifest via a `userConfig` schema, with typed fields, defaults, and secure storage for sensitive values.

**Details**

- Plugin manifests can include a `userConfig` block with named options of type `string`, `number`, `boolean`, `directory`, or `file`
- Each option supports `title`, `description`, `required`, `default`, `sensitive`, `min`/`max`, and `multiple` fields
- Option keys must be valid identifiers — they become `CLAUDE_PLUGIN_OPTION_<KEY>` environment variables in hooks
- Sensitive values are stored in secure storage (macOS keychain or `.credentials.json`), non-sensitive values in `settings.json`
- Available as `${user_config.KEY}` in MCP/LSP server config, hook commands, and (non-sensitive only) skill/agent content

**Evidence**

Plugin options schema and env var injection (search for `"CLAUDE_PLUGIN_OPTION_"`, `"User-configurable values this plugin needs"`)

### SSH Start Directory Setting

**What**

SSH remote configurations now support a `startDirectory` field to set the default working directory on the remote host.

**Usage**

`{ "sshRemotes": { "my-server": { "host": "example.com", "startDirectory": "~/projects" } } }` **Details** - Supports tilde expansion (e.g., `~/projects`) - If not specified, defaults to the remote user's home directory - Can be overridden by the `[dir]` positional argument in `claude ssh <config> [dir]` **Evidence** SSH start directory setting (search for `"startDirectory"`, `"Default working directory on the remote host"`)

### Memory Staleness Warnings

**What**

Memories recalled from CLAUDE.md and project memory files are now annotated with their age, warning Claude when recalled information may be outdated.

**Details**

- Memories older than 1 day display their age (e.g., "Memory (saved yesterday)" or "Memory (saved 5 days ago)")
- Memories older than 1 day include a system reminder: "Memories are point-in-time observations, not live state — claims about code behavior or file:line citations may be outdated. Verify against current code before asserting as fact."
- This helps prevent Claude from asserting stale file:line references or code behavior as current fact

**Evidence**

Memory age formatting and staleness warnings (search for `"Memories are point-in-time observations"`, `"claims about code behavior"`)

### Agent Message Queuing to Running Agents

**What**

When resuming a running agent via `Agent({resume: id})`, the prompt is now queued for delivery instead of throwing an error. Coordinators can also send messages to running agents via `SendMessage`.

**Details**

- If an agent is already running, calling `Agent({resume: id})` queues the prompt and returns a `queued_to_running` status
- The agent receives the queued message at its next tool-round boundary
- `SendMessage({to: "<name>", message: "..."})` can also queue messages to running local agents
- A coordinator message is rendered with: "The coordinator sent a message while you were working: [...] Address this before completing your current task."

**Evidence**

Agent message queue system (search for `"queued_to_running"`, `"Message queued for delivery"`, `"pendingMessages"`)

### Concurrent Session Detection

**What**

Claude Code now detects when multiple sessions are running simultaneously and offers a relevant tip.

**Details**

- Sessions register PID files in the Claude Code data directory
- When 2+ sessions are detected, a tip suggests: "Running multiple Claude sessions? Use /color and /rename to tell them apart at a glance."
- Session count is also reported via telemetry (`tengu_concurrent_sessions`)

**Evidence**

Concurrent session tracking (search for `"concurrentSessions"`, `"color-when-multi-clauding"`)

### SendMessage Tool Redesigned

The `SendMessage` tool schema has been simplified from a discriminated union with `type`/`recipient`/`content` fields to a more intuitive `to`/`message`/`summary` format. Agents now use `to: "<name>"` for direct messages and `to: "*"` for broadcasts. Structured protocol messages (shutdown requests, plan approvals) are sent as objects in the `message` field. A backward-compatibility shim (`backfillObservableInput`) translates old-format calls.

**Evidence**

Simplified SendMessage schema (search for `"Recipient: teammate name"`, `'to must be a bare teammate name or "*"'`)

### Auto Mode Circuit Breaker

Auto mode can now be remotely disabled via a server-side gate. When the circuit breaker is active, auto mode requests silently fall back to the default permission mode with a warning logged. The `claude auto-mode` subcommand is also hidden when auto mode is disabled.

**Evidence**

Auto mode circuit breaker (search for `"auto mode circuit breaker active (cached)"`, `"Cannot transition to auto mode"`)

### File Read Size Controlled by Feature Flag

File read limits (`maxSizeBytes` and `maxTokens`) are now configurable via the `tengu_amber_wren` feature flag, allowing server-side tuning of read limits without client updates. A new `CLAUDE_CODE_AUTO_COMPACT_WINDOW` environment variable also allows users to override the auto-compaction window size.

**Evidence**

Feature-flag-controlled read limits (search for `"tengu_amber_wren"`, `"CLAUDE_CODE_AUTO_COMPACT_WINDOW"`)

- Flag `tengu_amber_wren`: Not enough to say (read for one account on one subscription tier against v2.1.75; this account: no value returned, anonymous baseline: no value returned, compiled default: no gate table built for this version) These values were read against a different version of Claude Code, so treat them as the nearest reading available instead of one taken on this release.

### Background Task Monitor Distinction

The status bar now distinguishes between regular background tasks and monitors, showing counts like "2 background tasks, 1 monitor" instead of a single combined count.

**Evidence**

Monitor/task distinction in status line (search for `"Monitor details"`, `kind === "monitor"`)

### Shift+Arrow Navigation for Teammates

The keyboard shortcut to expand teammate views has changed from `↓` to `shift + ↓`. A new `shift + ↑` shortcut navigates upward through the teammate list.

**Evidence**

Updated keybindings (search for `"shift + ↓"`)

### Leader Idle State Display

When the team leader is idle but teammates are still working, the spinner now shows a distinct "Idle · teammates running" state instead of the generic working indicator.

**Evidence**

Leader idle state in spinner (search for `"· teammates running"`, `leaderIsIdle`)

### Session Metadata Enrichment

Session metadata returned by `listSessions` and `getSessionInfo` now includes `tag` (user-set session tag) and `createdAt` (creation timestamp). The `fileSize` field is now optional and only populated for local JSONL storage.

**Evidence**

Expanded session metadata schema (search for `"User-set session tag"`, `"Creation time in milliseconds since epoch"`)

### Marketplace Name Security Validation

Marketplace names now reject path traversal patterns — names containing `/`, `\`, `..` sequences, or consisting of just `.` are rejected with a clear error message.

**Evidence**

Path traversal validation (search for `'Marketplace name cannot contain path separators'`)

### Credential Redaction in Git Clone Logs

URLs containing embedded usernames or passwords are now redacted when logged during git clone operations, preventing accidental credential exposure in logs.

**Evidence**

URL credential redaction function `A96()` (search for `q.username = "***"`)

### Permission Mode Change Events

Permission mode changes (default, acceptEdits, bypassPermissions, auto, etc.) are now emitted as system status events on the outbound stream, enabling external integrations to track permission state.

**Evidence**

Permission mode event emission (search for `"permissionMode"`, `Tkq`)

### Skill/Prompt Aliases

Skills and prompts now support an `aliases` field, enabling multiple names for the same slash command.

**Evidence**

Aliases support in prompt definitions (search for `aliases: A.aliases`)

### Hook Source Tracking

Hooks now carry `hookSource` metadata indicating their origin (e.g., `plugin:name`, `skill:name`, or `settings`), improving debuggability.

**Evidence**

Hook source annotation (search for `"hookSource"`)

### Error Details on Prompt Too Long

When an API request fails with "prompt is too long", the error response now includes `errorDetails` with the full exception message, providing more diagnostic context.

**Evidence**

Error details propagation (search for `"errorDetails"`)

## Bug Fixes

- Fixed `readFileState` being recomputed from messages on every turn — the main session class now caches and reuses it, improving performance (search for `"readFileState"`)
- Removed redundant `existsSync` checks before `readFileSync` and `unlinkSync` calls, fixing potential race conditions (search for `unlinkSync`)
- Fixed the tag-clearing behavior: setting an empty tag now correctly clears it (`tag || void 0`) instead of keeping the empty string (search for `"currentSessionTag"`)
- Voice-enabled checks now additionally gate on `$I()`, preventing voice features from activating when conditions aren't fully met (search for `voiceEnabled`)
- The `user:file_upload` OAuth scope is now requested for first-party authenticated sessions (search for `"user:file_upload"`)
- Fixed async hook response rendering: previously only showed for PreToolUse/PostToolUse when tool hooks were enabled; now also shows for SessionStart and other hook types when session hooks are enabled (search for `"async_hook_response"`)

## Removed

- **Nested session restriction removed**: The check that prevented launching Claude Code inside another Claude Code session (via the `CLAUDECODE=1` environment variable) has been removed. Users can now nest sessions freely. (search for `"Nested sessions share runtime resources"` — present in v2.1.74, absent in v2.1.75)

- **Windows ProgramData deprecation warning removed**: The notification warning about migrating `C:\ProgramData\ClaudeCode\managed-settings.json` to `C:\Program Files\ClaudeCode\` has been removed, along with the associated detection logic. (search for `"programdata-deprecation-warning"` — present in v2.1.74, absent in v2.1.75)

## In Development

Features with infrastructure added but not yet enabled or partially gated.

### Opus 1M Context [Gradual Rollout]

**What**

The Opus 1M context window default is controlled by the `tengu_cobalt_compass` feature flag with a default of `false`.

**Status**

Feature-flagged, rolling out gradually.

**Details**

- The function `UH()` checks `tengu_cobalt_compass` — returns `false` by default
- Only applies to first-party users (not API key users or third-party)
- Excluded when `je()` (demo mode) or `ZC()` (certain restricted contexts) is active
- Once enabled server-side, migration is automatic

**Evidence**

Feature gate check (search for `"tengu_cobalt_compass"`) — `UH()` at line ~532570

- Flag `tengu_cobalt_compass`: On for this account, and not off by default (read for one account on one subscription tier against v2.1.75; this account: on, anonymous baseline: on, compiled default: no gate table built for this version) These values were read against a different version of Claude Code, so treat them as the nearest reading available instead of one taken on this release.