The script does not set error handling mode. The bash version uses set -e to exit on errors. In fish, consider adding set -e at the beginning to ensure the script exits on command failures, providing consistent behavior with the bash implementation.

The help text uses a hardcoded script name instead of a variable. The bash version uses 0ドル to dynamically show the script name that was invoked, which is more flexible and accurate. This fish version should use something like (status --current-filename) or basename of it to match the bash behavior and show the actual invoked script name.

The usage message in the error case also uses a hardcoded script name instead of dynamically referencing the invoked script. For consistency with the bash version and better usability, consider using a variable containing the script name.

Missing explanatory comment. The bash version has "Function to find the repository root by searching for existing project markers" which is more descriptive than just "Function to find the repository root". The additional context about "searching for existing project markers" helps explain what the function does. Consider adding this for better documentation.

Missing base-10 interpretation prefix. The bash version uses number=$((10#$number)) to force base-10 interpretation. This fish version only uses (math $number + 0) which may not properly handle numbers with leading zeros (e.g., "008" could be misinterpreted). This could lead to incorrect identification of the highest spec number when directory names have leading zeros.

Missing base-10 interpretation prefix. The bash version uses number=$((10#$number)) to force base-10 interpretation. This fish version only uses (math $number + 0) which may not properly handle numbers with leading zeros (e.g., "008" could be misinterpreted). This could lead to incorrect identification of the highest branch number when branch names have leading zeros.

Missing detailed comment. The bash version has "Function to check existing branches (local and remote) and return next available number" which is more descriptive. The fish version only has "Function to check existing branches" without mentioning "local and remote" or "return next available number". Consider adding the full description for better clarity.

Missing comment about remote fetching. The bash version has "Fetch all remotes to get latest branch info (suppress errors if no remotes)" which explains both the action and the error suppression strategy. The fish version lacks this comment. Consider adding it for better documentation.

Missing detailed comment about repository root detection. The bash version includes an explanatory comment: "Resolve repository root. Prefer git information when available, but fall back to searching for repository markers so the workflow still functions in repositories that were initialised with --no-git." This provides important context about the design decision. Consider adding this comment for better maintainability.

Missing detailed comment explaining generation logic. The bash version has: "Function to generate branch name with stop word filtering and length filtering" while fish version only says "Function to generate branch name with stop word filtering". The "and length filtering" part describes an important aspect of the function's behavior. Consider adding this for accuracy and consistency.

The stop words regex pattern is missing the word boundary anchors that are present in the bash version. The bash version uses grep -qiE "$stop_words" which effectively matches whole words. Without proper word boundary handling in fish, partial matches could occur. Consider revising the regex pattern to ensure only complete word matches are filtered.

Comment differs from bash version. The bash version says "Filter words: remove stop words and words shorter than 3 chars (unless they're uppercase acronyms in original)" which is more descriptive. The fish version says "Filter words" followed by "Keep words that are NOT stop words AND (length >= 3 OR are potential acronyms)" in a later comment. Consider matching the bash version's comment style for consistency.

The acronym detection logic differs from the bash version. The bash version checks if the word appears as uppercase in the original description using grep -q "\b${word^^}\b" with word boundaries. The fish version uses string match -q "*"(string upper $word)"*" which performs a substring match and could produce false positives. For example, if the word "id" appears anywhere in "valid", it would match. Consider using a more precise matching approach.

The fallback branch name generation logic differs from the bash version. The bash version uses tr '\n' '-' | sed 's/-$//' to join words and remove trailing hyphens, while the fish version uses string join '-'. While both achieve similar results, the bash version explicitly processes the cleaned output through tr '-' '\n' | grep -v '^$' | head -3 to split, filter empty strings, take first 3, then rejoin. The fish version uses string split '-' | string match -v '' | head -3 | string join '-' which should work equivalently. However, verify this produces identical results in edge cases.

Inconsistent comment format. The bash version has a more detailed comment explaining "Force base-10 interpretation to prevent octal conversion (e.g., 010 → 8 in octal, but should be 10 in decimal)". This fish version only says "Force base-10 interpretation" without the helpful explanation. For maintainability and clarity, consider adding the full explanation as in the bash version.

Missing base-10 interpretation prefix. The bash version uses $((10#$BRANCH_NUMBER)) to force base-10 interpretation and prevent octal conversion (e.g., "010" being interpreted as octal 8 instead of decimal 10). The fish version only uses (math $BRANCH_NUMBER + 0) which may not handle this edge case correctly. This could lead to incorrect branch numbering when branch numbers like 008, 009, 010, etc. are provided.

Missing comment for branch name validation section. The bash version includes a comment "Validate and truncate if necessary" after the main comment about GitHub's 244-byte limit. This helps clarify the purpose of the following code block. Consider adding this comment for consistency and clarity.

Comment style differs from bash version. The bash version says "Calculate how much we need to trim from suffix" followed by "Account for: feature number (3) + hyphen (1) = 4 chars" which provides helpful arithmetic. The fish version only has the first comment. Consider adding the detailed breakdown for better clarity.

Missing comment about truncation strategy. The bash version has "Truncate suffix at word boundary if possible" before the truncation line, explaining the intent. This comment is missing in the fish version. Consider adding it for better code documentation.