[BUG] Multiline claude_args with Bash tools containing spaces parsed incorrectly

[vertti]

Bug Description

When using multiline YAML for claude_args with Bash tool patterns that contain spaces (like Bash(git diff --name-only HEAD~1)), the SDK incorrectly parses the --allowedTools argument by splitting on spaces.

Reproduction

claude_args: |
  --max-turns 15
  --allowedTools Bash(git diff --name-only HEAD~1),Bash(git diff HEAD~1),Read,Glob,Grep

Expected Behavior

SDK should parse allowedTools as:

["Bash(git diff --name-only HEAD~1)", "Bash(git diff HEAD~1)", "Read", "Glob", "Grep"]

Actual Behavior

SDK parses allowedTools as:

["Bash", "git", "diff"]

From the logs:

SDK options: {
  "allowedTools": [
    "Bash",
    "git",
    "diff"
  ],
  ...
  "extraArgs": {
    "max-turns": "15",
    "name-only": "HEAD~1"
  },
  ...
}

Note that --name-only HEAD~1 is also incorrectly parsed as a separate extraArg.

Evidence

Full error:

SDK execution error: error: Claude Code process exited with code 1

Workaround

Put everything on a single line with quotes:

claude_args: --max-turns 15 --allowedTools "Bash(git diff --name-only HEAD~1),Bash(git diff HEAD~1),Read,Glob,Grep"

Environment

• Action version: anthropics/claude-code-action@v1
• Runner: ubuntu-latest
• Event: pull_request

Notes

The migration guide shows multiline claude_args examples, but they don't include Bash tools with spaces:

claude_args: |
  --max-turns 15
  --allowedTools Edit,Read,Write,Bash

The issue appears to be that shell-quote (or whatever parser is used) doesn't handle the multiline + spaces-in-arguments combination correctly.

[vertti]

Looked into this - the root cause is that shell-quote (which parses claude_args) follows shell semantics where spaces are delimiters. So --allowedTools Bash(git diff ...) gets split at each space, and --name-only even gets interpreted as a separate flag.

The fix is to quote the value: --allowedTools "Bash(git diff --name-only HEAD~1),Read,Glob,Grep"

This works in multiline YAML too:

claude_args: |
  --max-turns 15
  --allowedTools "Bash(git diff --name-only HEAD~1),Read,Glob,Grep"

I'm thinking we should add a warning when we detect patterns that look broken (like Bash(git without a closing paren, or standalone diff), plus update the docs to make the quoting requirement clearer.