Follow Discord
Sweep 27 Oct 2026 · 19:04Z Build v2.1.312 531 read Stable v2.1.308 Latest v2.1.312 Next v2.1.312 Feeds RSS JSON llms.txt llms-full.txt Unofficial
HomeDocsClaude Code CLI 24 Oct 2026
One change · claude-code

Customize sessions in self-hosted environments changedself-hosted-environments-configuration

Nearest release: v2.1.310, published 16 hours before 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 24 Oct 2026 14:13 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 24 Oct 2026 14:37 UTC.

Upstream edited
Recorded here
Lines+20added
Lines−0removed
From line 85 where the diff opens
First seen 14 Aug 2026 this site's first read of the page
Recorded edits36to this page, all time

#### Fix `Argument list too long` at session start

The whole hunk

from line 85, old and new numbered
/
lines
from line 85
8585* **Pass them through**: end the wrapper with `exec "$CLAUDE_RUNNER_CLAUDE_BIN" "$@"`, which forwards the file flags along with every other argument. Don't drop or rewrite them. If a session loses a prompt file flag, it runs without the instructions the control plane sent for it.
8686* **On a runner at v2.1.281 or later, a file flag you append replaces the server's, never adds to it**: each prompt file flag takes a single value and Claude Code keeps the last occurrence, so if you append `--append-system-prompt-file <path>` after `"$@"`, your file's contents replace the server's appended instructions. To add instructions on top of the server's, put them in the runner image's `CLAUDE.md`, which the runner [seeds into every session's user-level config](#how-each-session’s-config-is-assembled).
8787 
88#### Fix `Argument list too long` at session start
89 
90On Linux, if you join the control plane's prompt and your own text into one `--append-system-prompt` argument, the runner logs a line like this once the argument reaches 128 KB:
91 
92```text theme={null}
93Session <id> finished: failed — reason: child exited 126: /opt/wrapper.sh: line 9: /usr/local/bin/claude: Argument list too long
94```
95 
96Linux limits each single argument to 32 memory pages, or 128 KB with the usual 4 KB pages. The figure from `getconf ARG_MAX`, often 2 MB, is a separate limit on all arguments and the environment together.
97 
98On Claude Code v2.1.283 or later, leave the file flags in `"$@"` and pass only your own text as `--append-system-prompt`. Claude Code [uses both](https://code.claude.com/docs/en/cli-reference.md#system-prompt-flags), the control plane's prompt first and then your own text:
99 
100```bash theme={null}
101exec "$CLAUDE_RUNNER_CLAUDE_BIN" "$@" --append-system-prompt "$(cat /opt/team-instructions.md)"
102```
103 
104On Linux, if your own text reaches 128 KB, move it to the runner image's `CLAUDE.md`, because it's still one argument.
105 
106On v2.1.281 or v2.1.282, that command exits with `Cannot use both --append-system-prompt and --append-system-prompt-file`. On earlier versions, your text replaces the control plane's prompt with no error. On any of them, update first, or move your own text to `CLAUDE.md`.
107 
88108### Provision credentials scoped to the session creator
89109 
90110Use the `decode-token` subcommand to read claims from the session JWT. It reads the token from an argument, from `CLAUDE_CODE_SESSION_ACCESS_TOKEN`, or from stdin, in that order; see [Verify the token inside the session](https://code.claude.com/docs/en/self-hosted-environments-identity.md#verify-the-token-inside-the-session) for what it checks. The example below decodes the creator identity, exchanges it for short-lived AWS credentials, and execs into Claude Code:
Feedback