Claude Code v2.1.172 Changelog

gistfile1.txt

# Changelog for version 2.1.172

## Summary

Version 2.1.172 ships the Artifact tool — a new capability letting Claude publish HTML and Markdown files to private claude.ai web pages — alongside improved ultra (cloud review) error messages that guide users through auth requirements. The release also renames "Remote Control" status labels to `/rc`, improves Chrome browser tool loading instructions to emphasize batching, and overhauled the team memory prompt with a clearer two-step save process.


## New Features


### Artifact Tool

What: Claude can now render an HTML or Markdown file to a private, shareable web page hosted on claude.ai. The resulting URL can be shared with teammates.

Usage:
```
Artifact(file_path="report.html", favicon="📊")
Artifact(file_path="notes.md", favicon="📝", label="v2")
```

Details:
- Accepts `.html`, `.htm`, and `.md` files; Markdown is converted to styled HTML automatically
- The `favicon` parameter (required) sets the browser-tab emoji icon — use one or two emoji, no markup
- The optional `label` parameter provides a human-readable version label shown in the version picker
- The optional `url` parameter lets Claude redeploy to an existing artifact URL the user provides
- A strict CSP blocks all external resources — inline all CSS/JS and embed assets as data: URIs
- Same file path → same URL on redeploy; different file path → new URL
- Controlled by the `CLAUDE_CODE_DISABLE_ARTIFACT` environment variable and the `disableArtifact` setting
- Gated by feature flag `tengu_cobalt_plinth`; enabled for eligible claude.ai accounts

Evidence: Artifact tool implementation (search for `"Render an HTML or Markdown file to an Artifact"` and `uAH = "Artifact"`)


### --plugin-dir-no-mcp Flag

What: A new `--plugin-dir-no-mcp` flag that loads a plugin directory without also reading its `.mcp.json` file. Useful when the SDK host already owns and manages the plugin's MCP connections.

Usage:
```bash
claude --plugin-dir-no-mcp <path>
```

Details:
- Behaves exactly like `--plugin-dir` except the engine skips `.mcp.json` / `mcpServers` discovery for that plugin
- Equivalent behavior is also available as a setting: `noMcp: true` in the plugin frontmatter
- Intended for SDK hosts that register MCP servers themselves rather than delegating to the engine

Evidence: New flag definition and help text (search for `"Like --plugin-dir but the engine will not read this plugin's .mcp.json"`)


### Ultra (Cloud Review) — Improved Auth Error Messages

What: When ultra (cloud review) is unavailable, Claude Code now surfaces specific, actionable error messages depending on the exact auth state rather than a single generic message.

Details:
- API key auth → "ultra (cloud review) requires claude.ai account auth. Unset ANTHROPIC_API_KEY … to use ultra."
- Missing profile scope → "ultra (cloud review) requires a full-scope login token — run `claude auth login` to use it"
- Not yet in rollout → "ultra (cloud review) isn't enabled for your account yet — run `claude auth login` to refresh your entitlements"
- Unauthenticated entirely → "ultra (cloud review) requires a claude.ai account — sign in to claude.ai to use it"
- All error messages include a link to `https://code.claude.com/docs/en/ultrareview`

Evidence: Error routing function (search for `"ultra (cloud review) requires claude.ai account auth"`)


### URL Provenance Check for web_fetch

What: `web_fetch` now enforces a provenance check — it can only retrieve URLs that appeared in a user message or a prior `web_fetch` result. Attempts to fetch URLs outside this set present a permission prompt asking the user to approve.

Details:
- If the user approves, the fetch proceeds; if denied or timed out, Claude receives an error
- Timeout message: "The permission request for this URL was not answered in time. Ask the user to approve the fetch or include the URL in a message, then try again."
- The error type is `PROVENANCE_REQUIRED`
- Suppressed in bypassPermissions and dontAsk modes

Evidence: Provenance enforcement and prompt (search for `"URL not in provenance set. web_fetch can only retrieve URLs that appeared in a user message"`)


### /memories/export Route

What: A new internal `/memories/export` route has been registered, enabling memory export functionality.

Evidence: New constant (search for `"/memories/export"`)


### ShowOnboardingRolePicker Tool (Cowork)

What: A new internal tool for Cowork onboarding that renders an interactive role-picker chip row. Users can tap a chip (e.g. "Legal", "Engineering") to select their role and trigger automatic plugin installation.

Details:
- Blocks until the user responds: chip click, free-form text entry, or dismissal
- Returns `{"role": "..."}` on selection, `{"dismissed": true}` on cancel, `{}` on confirm-without-role
- Only enabled in Cowork sessions; not available in normal conversations
- Gated via `KOf` (Cowork environment check)

Evidence: Tool definition (search for `"Render a clickable role-picker chip row during Cowork onboarding"`)


### CLAUDE_CODE_CHILD_SESSION Environment Variable

What: A new `CLAUDE_CODE_CHILD_SESSION` environment variable that marks a session as a child session, suppressing certain persistence behaviors (e.g. session data is not persisted when this is set alongside other child-session conditions).

Evidence: New env var check (search for `"CLAUDE_CODE_CHILD_SESSION"`)


### CLAUDE_CODE_SKIP_PLUGIN_MCP_SERVERS

What: A new environment variable that, when set, skips MCP server discovery for plugin directories during startup.

Evidence: Log message (search for `"CLAUDE_CODE_SKIP_PLUGIN_MCP_SERVERS is set"`)


## Improvements


### Remote Control Status Labels Renamed to /rc

What: The status-bar labels for the Remote Control / remote session feature have been shortened from "Remote Control active / connecting / failed / reconnecting" to `/rc active`, `/rc connecting…`, `/rc failed`, `/rc reconnecting`.

Evidence: Status label function (search for `"/rc active"` and `"/rc failed"`)


### Chrome Browser Tools: Batch ToolSearch Loading

What: The Chrome browser automation system prompt now explicitly instructs Claude to load all needed tools in a single `ToolSearch` call using a comma-separated `select:` query, rather than one call per tool.

Details:
- New guidance: "Do NOT load tools one at a time; each separate ToolSearch call wastes a full round-trip"
- The recommended starter set covers `tabs_context_mcp`, `navigate`, `computer`, `read_page`, and `tabs_create_mcp` in one call
- Task-specific extras (recording, forms, console debugging) should be added to that same call when the task obviously needs them

Evidence: Updated browser automation prompt (search for `"batch every tool you expect to need into ONE ToolSearch call"`)


### Team Memory: Two-Step Save Process Instructions

What: The team memory system prompt has been overhauled with clearer, step-by-step guidance for saving memories. When using indexed memory, the instructions now explicitly describe a two-step process (write the memory file, then add a pointer to the index).

Details:
- Step 1: Write memory to its own file using the frontmatter format
- Step 2: Add a pointer entry (`- [Title](file.md) — one-line hook`) to the index file
- Index entries are capped at ~150 characters
- Clarified that team memory directories already exist — no need to run `mkdir`
- Read-only sessions now receive: "If the user asks you to remember something, explain that memory is read-only in this session."

Evidence: New team memory prompt builder (search for `"**Step 1** — write the memory to its own file in"`)


### AWS Region Display Shows Configuration Source

What: The AWS region display in Bedrock configuration now shows where the region came from — environment variable, AWS shared config file, or the built-in default — rather than just the region name.

Details:
- `us-east-1` (from environment) → shown as-is
- From `~/.aws/config` → shown as `us-east-1 (from AWS config)`
- Default fallback → shown as `us-east-1 (default — set AWS_REGION or add a region to your AWS config)`

Evidence: Region source display function (search for `"(from AWS config)"` and `"(default — set AWS_REGION or add a region to your AWS config)"`)


### --bg / --pool Conflict Error Message Improved

What: The error shown when combining `--bg` with another backend flag now distinguishes between `--pool` and `--cloud`.

Details:
- Using `--bg` with `--pool`: "Use `claude -p '<task>' --pool <pool_id>` directly to start a session on the pool."
- Using `--bg` with `--cloud`: "Use `claude --cloud '<task>'` directly to start a cloud session."

Evidence: Updated error message function (search for `"--bg and --pool are different backends"`)


### "Help improve our AI models" Renamed

What: The consent UI string "Help improve Claude" has been renamed to "Help improve our AI models" across all display states (ON, OFF, OFF for domain emails).

Evidence: String changes (search for `"Help improve our AI models"` — previously `"Help improve Claude"`)


### Plugin Disuse Tracking

What: Claude Code now tracks the last time each plugin was used (`lastUsedAt` and `lastUsedNumStartups`). This data enables the tip system to surface a warning when a plugin hasn't been used in a while.

Details:
- Tip shown: "You haven't used the [plugin] in a while. It still adds startup and context cost — review it with…"
- Tracks both calendar days and session count since last use

Evidence: Plugin usage tracking functions (search for `"plugin in a while. It still adds startup and context cost"`)


### MCP OAuth Token Clearing: Preserve Client Registration

What: When clearing MCP OAuth tokens, Claude Code can now optionally preserve the client registration (client ID) while discarding only the access/refresh tokens. This avoids a full re-registration flow when tokens simply need refreshing.

Details:
- When `preserveClientRegistration: true` is passed, only `accessToken`, `refreshToken`, `expiresAt`, and `scope` are cleared
- Log message: "Cleared stored tokens (preserved client registration)"

Evidence: Updated token-clear function (search for `"Cleared stored tokens (preserved client registration)"`)


### Fullscreen Feedback Prompt Simplified

What: The fullscreen mode exit survey prompt has been simplified. The old prompt included the parenthetical "(optional, Enter to skip)"; the new prompt is more direct.

Evidence: String change (old: `"To help us make fullscreen mode better, what made you switch back? (optional, Enter to skip)"` → new: `"To help us make fullscreen mode better, what made you switch back?"`)


### Structured Output Retraction Error Messages

What: When a model fallback causes structured output to be retracted and no retry succeeds, Claude Code now surfaces a more specific error message instead of the previous "the cloud agent called StructuredOutput but every attempt failed schema validation."

New message: "the cloud agent called StructuredOutput but no attempt produced a surviving valid output (failed schema validation, or retracted by a model fallback)"

Evidence: Updated error string (search for `"retracted by a model fallback and no retry produced a valid result"`)


### Subagent Model Allowlist Warning Improved

What: When a subagent is configured with a model that is not in the `availableModels` allowlist, the warning message now distinguishes between inheriting the parent model vs. using the default teammate model.

Details:
- Subagent case: "Subagent model `X` is not in the availableModels allowlist; inheriting the parent model instead"
- Teammate case: "Teammate model `X` is not in the availableModels allowlist; using the default teammate model instead"

Evidence: New warning functions (search for `"Subagent model"` and `"Teammate model"` with allowlist messages)


### Trusted Device Error Message Centralized

What: The "not enrolled as a trusted device" error message is now generated from a single function, ensuring consistent text: "this device is not enrolled as a trusted device; run /login to enroll".

Evidence: Centralized message function (search for `"this device is not enrolled as a trusted device; run /login to enroll"`)


### Session Status Update Timestamps

What: When a session's status changes, a separate `statusUpdatedAt` timestamp is now recorded alongside the general `updatedAt` timestamp, enabling more precise tracking of status transition times.

Evidence: Updated session state function (search for `"statusUpdatedAt"` alongside `"updatedAt"`)


## Bug Fixes

- Deep-link injection guard: `--handle-uri` invocations with extra arguments after the URI are now rejected with an explanatory message, blocking URI-based argument injection. (search for `"claude: rejected deep-link invocation — unexpected arguments after the URI"`)

- Artifact upload precondition retry: Uploading an artifact now detects HTTP 412 (create-only precondition failed) and returns a clear message: "upload 412: this version was already written (create-only precondition). Re-run publish to mint a fresh version." (search for `"this version was already written (create-only precondition)"`)

- Transcript third-party marker filtering: When sharing session history, transcripts containing third-party markers are now silently excluded rather than included verbatim. The raw transcript and recent sessions lists are independently filtered. (search for `"rawTranscriptJsonl withheld from session history: contains_3p_transcript_markers"`)

- Model `[1m]` suffix handling made case-insensitive: Functions that strip or normalize the `[1m]` model suffix now use case-insensitive matching (`/\[1m\]/i`), preventing edge cases where mixed-case suffixes were not recognized. (search for `"/\\[1m\\]/i"`)

- Interactive command detection message updated: The message shown when a command appears blocked on an interactive prompt now says "Stop this task" instead of "Kill this task", matching the updated UI terminology. (search for `"The command is likely blocked on an interactive prompt. Stop this task"`)

- tmux session cleanup label corrected: The worktree cleanup option now reads "Keep worktree, end tmux session" instead of the previous "Keep worktree, kill tmux session". (search for `"Keep worktree, end tmux session"`)