Feature/support branch prefix by leoxiao2012 · Pull Request #2541 · github/spec-kit

leoxiao2012 · 2026-05-13T10:22:28Z

Support custom branch prefixes (e.g. feature/, bugfix/, hotfix/) in auto-generated git branches. The agent chooses the prefix based on context and passes --prefix to the script. Number extraction now handles prefixed branch names correctly.

Description

Add --prefix (Bash) / -Prefix (PowerShell) option to create-new-feature scripts, enabling custom branch name prefixes such as feature, bugfix, or hotfix.

Motivation: Auto-generated branch names have a fixed format like 001-user-auth, which doesn't fit workflows like GitFlow that require category prefixes. Since the prefix varies by context (feature/bugfix/hotfix), it is not suitable as a fixed
config — the agent decides the appropriate prefix based on the nature of the work.

Changes:

Add --prefix argument to 4 scripts (Bash × 2 + PowerShell × 2)
Auto-append /, producing deterministic {prefix}/{number}-{short-name} format (e.g., --prefix "feature" → feature/001-auth)
Fix _extract_highest_number / Get-HighestNumberFromNames to correctly extract numbers from prefixed branch names (e.g., feature/003-name), preventing duplicate numbering
Update branch name construction and 244-byte truncation logic to account for prefix length
Update speckit.git.feature.md command instructions to guide agents on prefix selection
Update extensions/git/README.md with --prefix usage documentation

Backward compatible: omitting --prefix produces identical behavior to before.

Testing

bash create-new-feature.sh --dry-run --json --prefix "feature" --short-name "auth" "test" → {"BRANCH_NAME":"feature/001-auth","FEATURE_NUM":"001","DRY_RUN":true}
Without prefix — backward compatible → {"BRANCH_NAME":"001-auth","FEATURE_NUM":"001","DRY_RUN":true}
--help output includes new option

AI Disclosure

I did not use AI assistance for this contribution
I did use AI assistance (describe below)

Code generated by Claude Code (Opus 4.6), reviewed and verified manually.

Support custom branch prefixes (e.g. feature/, bugfix/, hotfix/) in auto-generated git branches. The agent chooses the prefix based on context and passes --branch-prefix to the script. Number extraction now handles prefixed branch names correctly. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Ensures consistent {prefix}/{number}-{suffix} format even when the user omits the trailing slash (e.g. --branch-prefix "feature" becomes "feature/"). Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Update command file and README to show prefixes without trailing slash and explain the auto-append behavior and final format. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Shorter flag name consistent with --short-name and --number style. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Copilot

Pull request overview

Adds support for custom branch name prefixes (e.g., feature/, bugfix/, hotfix/) to the core and git-extension create-new-feature scripts, ensuring sequential number detection works correctly even when branches are prefixed. This aligns Spec Kit’s auto-generated branch naming with workflows like GitFlow while keeping prefix-less behavior backward compatible.

Changes:

Add --prefix (Bash) / -Prefix (PowerShell) options and normalize prefixes to end with /.
Update sequential number extraction to handle prefix/003-name formats and adjust 244-char truncation logic for prefix length.
Document prefix selection/usage in the git extension README and speckit.git.feature command instructions.

Show a summary per file

File	Description
scripts/powershell/create-new-feature.ps1	Adds `-Prefix`, normalizes it, and includes it in branch construction and truncation math.
scripts/bash/create-new-feature.sh	Adds `--prefix`, normalizes it, and includes it in branch construction and truncation math.
extensions/git/scripts/powershell/create-new-feature.ps1	Mirrors core PowerShell script changes for the git extension.
extensions/git/scripts/bash/create-new-feature.sh	Mirrors core Bash script changes for the git extension.
extensions/git/README.md	Documents optional branch prefixes and the resulting naming format.
extensions/git/commands/speckit.git.feature.md	Instructs agents how to choose prefixes and how to pass them to scripts.

Copilot's findings

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Files reviewed: 6/6 changed files
Comments generated: 3

The rename from --branch-prefix to --prefix missed the error-path usage messages in three scripts. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Copilot

Copilot's findings

Files reviewed: 6/6 changed files
Comments generated: 7

mnriem

Please address Copilot feedback

Separate BRANCH_NAME (git ref, may include prefix like feature/) from FEATURE_DIR_NAME (directory-safe, no prefix) so that specs/ paths and sequential-number detection remain correct when a branch prefix is used. Also adds prefix validation (reject embedded slashes, trim whitespace) and 31 new pytest tests covering --prefix behavior across bash, ps1, and extension scripts. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Copilot

Copilot's findings

Files reviewed: 7/7 changed files
Comments generated: 9

mnriem · 2026-05-14T20:09:08Z

Please address Copilot feedback. If not applicable, please explain why

…length constant Add input validation for --prefix/-Prefix across all 4 scripts (Bash, PowerShell, extension variants): - Reject non-ASCII characters and special characters - Require prefix to start with a letter or digit (^[a-z0-9][-a-z0-9]*$) - Enforce max length of 16 characters via extracted MAX_PREFIX_LEN constant - Reject slash-only values (e.g. "/", "//") and embedded slashes - Add comprehensive test coverage for all edge cases Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

leoxiao2012 · 2026-05-17T17:13:42Z

Add input validation for --prefix/-Prefix across all 4 scripts (Bash,
PowerShell, extension variants):

Reject non-ASCII characters and special characters
Require prefix to start with a letter or digit (^[a-z0-9][-a-z0-9]*$)
Enforce max length of 16 characters via extracted MAX_PREFIX_LEN constant
Reject slash-only values (e.g. "/", "//") and embedded slashes
Add comprehensive test coverage for all edge cases

Copilot

Copilot's findings

Files reviewed: 7/7 changed files
Comments generated: 8

…alidation Reject any '/' in --prefix outright instead of stripping trailing slash then validating — simpler logic, clearer error message. Also switch PowerShell -notmatch to -cnotmatch so uppercase prefixes are correctly rejected (case-insensitive -notmatch let [a-z] match uppercase). Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

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Copilot

Copilot's findings

Files reviewed: 7/7 changed files
Comments generated: 7

mnriem · 2026-05-27T15:59:12Z

Please address Copilot feedback

Copilot

Copilot's findings

Files reviewed: 7/7 changed files
Comments generated: 0 new

mnriem · 2026-06-02T15:18:50Z

Please address test & lint errors

Update test assertions to expect "must not contain slashes" error message and reject trailing slashes, matching the current validation logic that disallows any slash in --prefix. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Copilot

Copilot's findings

Files reviewed: 7/7 changed files
Comments generated: 2

Copilot

Copilot's findings

Files reviewed: 7/7 changed files
Comments generated: 2

    # Calculate how much we need to trim from suffix
    # Account for prefix length: timestamp (15) + hyphen (1) = 16, or sequential (3) + hyphen (1) = 4
-    PREFIX_LENGTH=$(( ${#FEATURE_NUM} + 1 ))
+    PREFIX_LENGTH=$(( ${#BRANCH_PREFIX} + ${#FEATURE_NUM} + 1 ))


    # Calculate how much we need to trim from suffix
    # Account for prefix length: timestamp (15) + hyphen (1) = 16, or sequential (3) + hyphen (1) = 4
-    $prefixLength = $featureNum.Length + 1
+    $prefixLength = $Prefix.Length + $featureNum.Length + 1


mnriem

Please address Copilot feedback

leoxiao2012 and others added 4 commits May 13, 2026 17:59

fix(git): auto-append '/' to branch prefix if missing

46e42dc

Ensures consistent {prefix}/{number}-{suffix} format even when the user omits the trailing slash (e.g. --branch-prefix "feature" becomes "feature/"). Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

docs(git): update branch prefix docs — trailing slash is optional

328475e

Update command file and README to show prefixes without trailing slash and explain the auto-append behavior and final format. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

refactor(git): rename --branch-prefix to --prefix

6c61bff

Shorter flag name consistent with --short-name and --number style. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

leoxiao2012 requested a review from mnriem as a code owner May 13, 2026 10:22

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Comment thread extensions/git/scripts/bash/create-new-feature.sh Outdated

Comment thread scripts/powershell/create-new-feature.ps1

Comment thread extensions/git/scripts/powershell/create-new-feature.ps1

fix(git): add missing --prefix/-Prefix in error usage strings

55ff21f

The rename from --branch-prefix to --prefix missed the error-path usage messages in three scripts. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

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Merge branch 'main' into feature/support-branch-prefix

8a6ec6e

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leoxiao2012 force-pushed the feature/support-branch-prefix branch from 8d06059 to aaeafac Compare June 1, 2026 16:09

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leoxiao2012 force-pushed the feature/support-branch-prefix branch from aaeafac to 276d051 Compare June 3, 2026 07:51

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leoxiao2012 dismissed mnriem’s stale review via c5ef6cc June 3, 2026 07:54

leoxiao2012 force-pushed the feature/support-branch-prefix branch from 276d051 to c5ef6cc Compare June 3, 2026 07:54

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Comment thread extensions/git/commands/speckit.git.feature.md Outdated

Comment thread extensions/git/README.md Outdated

fix(docs): mark prefix as optional using bracket

305e257

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