Error reference changederrors
Nearest release: v2.1.317, published 6 hours after upstream edited the page. Shown because the two are within 24 hours of each other. Nothing here says the release caused the edit.
Upstream edited this page at 2 Nov 2026 17:30 UTC, give or take a minute or two: the time comes from Anthropic’s own sitemap rather than from a commit. This site recorded the change at 2 Nov 2026 17:37 UTC.
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Recorded edits219to this page, all time
### Setting blocks writes outside the working directories ### Writes to Claude Code settings files are blocked
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322322| `MCP server "<name>" tool "<tool>" timed out after <N>s. The server asked the user a question, and no answer came before the time limit.` | [Tool errors](#mcp-tool-call-timed-out-with-the-servers-question-unanswered) |
323323| `would be spawned with zero tools — refusing` | [Tool errors](#agent-would-be-spawned-with-zero-tools) |
324324| `File is covered by a Read deny rule in your permission settings` | [Tool errors](#file-is-covered-by-a-read-deny-rule) |
325| `<path> is outside <dirs>; the permissions.blockWritesOutsideWorkingDirectories setting blocks writes outside the working directories` | [Tool errors](#setting-blocks-writes-outside-the-working-directories) |
326| `<path>: Writes outside the working directories are blocked (permissions.blockWritesOutsideWorkingDirectories)` | [Tool errors](#setting-blocks-writes-outside-the-working-directories) |
327| `Writes to Claude Code settings files are blocked while permissions.blockWritesOutsideWorkingDirectories is on` | [Tool errors](#writes-to-claude-code-settings-files-are-blocked) |
325328| `cannot contain null bytes (\0)` | [Tool errors](#path-cannot-contain-null-bytes) |
326329| `Path contains null bytes` | [Tool errors](#path-cannot-contain-null-bytes) |
327330| `command contains the invisible character U+FEFF (byte order mark) or U+180E (Mongolian vowel separator), and was not run` | [Tool errors](#command-contains-an-invisible-character) |
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25022505
25032506### MCP tool name over 128 characters
25042507
2505An MCP server lists a tool whose full name, such as `mcp__<server>__<tool>`, is longer than the 128 characters the API accepts. Claude Code [leaves that tool out of the tools it sends to Claude](https://code.claude.com/docs/en/mcp.md#tools-with-names-longer-than-128-characters), and the server's other tools keep working. In a session you start with `claude --debug` from your shell, Claude Code writes this message to the debug log at `~/.claude/debug/<session-id>.txt`:
2506
2507```text theme={null}
2508Tool "mcp__<server>__<tool>" is not sent to Claude: its name has <N> characters and the API accepts at most 128
2509```
2510
2511**What to do:**
2512
2513* If you maintain the server
2508An MCP server lists a tool whose full name, such as `mcp__<server>__<tool>`
No line in this hunk matches that.