Backprop: Bug-to-Spec Protocol
JuliusBrussee/cavekit
After a bug is found, traces its root cause and feeds a new testable invariant back into the project spec so the bug class can't recur.
Generate a custom checklist for the current feature based on user requirements.
$ npx skills add kunstmusik/blue --skill speckit-checklist -a claude-codeProject install by default; add -g for ~/.claude/skills/.
$ gh skill install kunstmusik/blue speckit-checklist --agent claude-codeProject scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).
$ git clone --depth 1 https://github.com/kunstmusik/blue.git skills-src && mkdir -p .claude/skills && cp -r skills-src/.agents/skills/speckit-checklist .claude/skills/speckit-checklist && rm -rf skills-srcUse ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.
Claude Code skills documentation · loads skills from .claude/skills/
Install the "speckit-checklist" agent skill from https://github.com/kunstmusik/blue/tree/develop/.agents/skills/speckit-checklist into .claude/skills/speckit-checklist/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "speckit-checklist", then confirm the skill loads.Claude Code copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$skill-installer install https://github.com/kunstmusik/blue/tree/develop/.agents/skills/speckit-checklistType this inside Codex. $skill-installer <name> installs a curated skill from openai/skills. The installer writes to $CODEX_HOME/skills (default ~/.codex/skills). Restart Codex if the skill does not show up.
$ npx skills add kunstmusik/blue --skill speckit-checklist -a codexProject install goes to .agents/skills/; add -g for ~/.codex/skills/.
$ gh skill install kunstmusik/blue speckit-checklist --agent codexProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/kunstmusik/blue.git skills-src && mkdir -p .agents/skills && cp -r skills-src/.agents/skills/speckit-checklist .agents/skills/speckit-checklist && rm -rf skills-srcUse ~/.agents/skills/ instead of .agents/skills for a personal install.
Codex skills documentation · loads skills from .agents/skills/
Install the "speckit-checklist" agent skill from https://github.com/kunstmusik/blue/tree/develop/.agents/skills/speckit-checklist into .agents/skills/speckit-checklist/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "speckit-checklist", then confirm the skill loads.Codex copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add kunstmusik/blue --skill speckit-checklist -a cursorProject install goes to .agents/skills/; add -g for ~/.cursor/skills/.
$ gh skill install kunstmusik/blue speckit-checklist --agent cursorProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/kunstmusik/blue.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/.agents/skills/speckit-checklist .cursor/skills/speckit-checklist && rm -rf skills-srcUse ~/.cursor/skills/ instead of .cursor/skills for a personal install.
Cursor skills documentation · loads skills from .cursor/skills/, .agents/skills/, .claude/skills/, .codex/skills/
Install the "speckit-checklist" agent skill from https://github.com/kunstmusik/blue/tree/develop/.agents/skills/speckit-checklist into .cursor/skills/speckit-checklist/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "speckit-checklist", then confirm the skill loads.Cursor copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gemini skills install https://github.com/kunstmusik/blue.git --path .agents/skills/speckit-checklist--scope user (default) or --scope workspace; --path is the subfolder of the repo that holds the skill; --consent skips the security confirmation prompt.
$ npx skills add kunstmusik/blue --skill speckit-checklist -a gemini-cliProject install goes to .agents/skills/; add -g for ~/.gemini/skills/.
$ gh skill install kunstmusik/blue speckit-checklist --agent gemini-cliProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/kunstmusik/blue.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/.agents/skills/speckit-checklist .gemini/skills/speckit-checklist && rm -rf skills-srcUse ~/.gemini/skills/ instead of .gemini/skills for a personal install, then run /skills reload.
Gemini CLI skills documentation · loads skills from .gemini/skills/, .agents/skills/
Install the "speckit-checklist" agent skill from https://github.com/kunstmusik/blue/tree/develop/.agents/skills/speckit-checklist into .gemini/skills/speckit-checklist/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "speckit-checklist", then confirm the skill loads.Gemini CLI copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gh skill install kunstmusik/blue speckit-checklistInstalls for Copilot at project scope by default; add --scope user for a personal install. Preview a skill first with gh skill preview. Needs GitHub CLI 2.90.0 or later (public preview).
$ npx skills add kunstmusik/blue --skill speckit-checklist -a github-copilotProject install goes to .agents/skills/; add -g for ~/.copilot/skills/.
$ git clone --depth 1 https://github.com/kunstmusik/blue.git skills-src && mkdir -p .github/skills && cp -r skills-src/.agents/skills/speckit-checklist .github/skills/speckit-checklist && rm -rf skills-srcUse ~/.copilot/skills/ instead of .github/skills for a personal install. Commit .github/skills so cloud agent and code review can use it.
GitHub Copilot skills documentation · loads skills from .github/skills/, .claude/skills/, .agents/skills/
Install the "speckit-checklist" agent skill from https://github.com/kunstmusik/blue/tree/develop/.agents/skills/speckit-checklist into .github/skills/speckit-checklist/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "speckit-checklist", then confirm the skill loads.GitHub Copilot copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add kunstmusik/blue --skill speckit-checklist -a opencodeOpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.
$ gh skill install kunstmusik/blue speckit-checklist --agent opencodeProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/kunstmusik/blue.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/.agents/skills/speckit-checklist .opencode/skills/speckit-checklist && rm -rf skills-srcUse ~/.config/opencode/skills/ instead of .opencode/skills for a personal install.
OpenCode skills documentation · loads skills from .opencode/skills/, .claude/skills/, .agents/skills/
Install the "speckit-checklist" agent skill from https://github.com/kunstmusik/blue/tree/develop/.agents/skills/speckit-checklist into .opencode/skills/speckit-checklist/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "speckit-checklist", then confirm the skill loads.OpenCode copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
speckit-checklistGenerate a custom checklist for the current feature based on user requirements.
Speckit Checklist is an agent skill from kunstmusik/blue. Generate a custom checklist for the current feature based on user requirements.
Its SKILL.md is about 5.6k tokens, which your agent loads only when the skill is triggered. It is a single SKILL.md file with no bundled scripts. Compatibility notes: Requires spec-kit project structure with .specify/ directory
It sits in Development, covering Spec-driven development. The repository describes itself as: Blue - An Integrated Music Environment. The licence is GPL-3.0.
8 steps, taken from the first numbered list in SKILL.md.
Read from SKILL.md and the folder at commit 3c32d58. It shows what the files ask for, not the result of running them.
Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.
From allowed-tools in the SKILL.md frontmatter.
No scripts in the folder and no shell commands in SKILL.md (its code samples are markdown).
From the folder's file list and the shell code blocks in SKILL.md.
No URLs in SKILL.md.
From URLs in SKILL.md, links to its own repository left out.
Names no API keys, tokens, secrets or passwords.
From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.
Requires spec-kit project structure with .specify/ directory
From compatibility in the SKILL.md frontmatter.
Speckit Checklist loads about 5.6k tokens when it runs. Until then it costs about 24 tokens; SKILL.md has 2,575 words of instructions outside code blocks.
Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.
The automated check found no risky patterns in SKILL.md.
Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.
The full file from kunstmusik/blue at commit 3c32d58, republished under its GPL-3.0 licence (© kunstmusik). 2,575 words, ~5,641 tokens.
.claude/skills/speckit-checklist/SKILL.md (or your agent's skills folder).CRITICAL CONCEPT: Checklists are UNIT TESTS FOR REQUIREMENTS WRITING - they validate the quality, clarity, and completeness of requirements in a given domain.
NOT for verification/testing:
FOR requirements quality validation:
Metaphor: If your spec is code written in English, the checklist is its unit test suite. You're testing whether the requirements are well-written, complete, unambiguous, and ready for implementation - NOT whether the implementation works.
Ownership and checkbox lifecycle:
[x] means the reviewer determined the requirements-quality criterion is satisfied.[x] does NOT mean implementation work is complete.[x].checklists/requirements.md is a separate built-in spec-quality checklist maintained by $speckit-specify and $speckit-clarify; do not treat that exception as applying to custom checklists generated here.$ARGUMENTSYou MUST consider the user input before proceeding (if not empty).
Check for extension hooks (before checklist generation):
.specify/extensions.yml exists in the project root.hooks.before_checklist key.specify/extensions.yml could not be read (include the parser error) and that no hooks were checked, including any mandatory (optional: false) hooks registered there, then continue normallyenabled is explicitly false. Treat hooks without an enabled field as enabled by default.condition expressions:condition field, or it is null/empty, treat the hook as executablecondition, skip the hook and leave condition evaluation to the HookExecutor implementation.) with hyphens (-). For example, speckit.git.commit → $speckit-git-commit.optional flag:optional: true):## Extension Hooks
**Optional Pre-Hook**: {extension}
Command: `/{command}`
Description: {description}
Prompt: {prompt}
To execute: `/{command}`optional: false):## Extension Hooks
**Automatic Pre-Hook**: {extension}
Executing: `/{command}`
EXECUTE_COMMAND: {command}
Wait for the result of the hook command before proceeding to the Execution Steps.{command} id shown above, e.g. a skills-mode agent runs it as /skill:speckit-... or $speckit-...). Emitting the block alone does not run the hook..specify/extensions.yml does not exist, skip silentlySetup: Run .specify/scripts/bash/check-prerequisites.sh --json --template checklist-template from repo root and parse JSON for FEATURE_DIR, AVAILABLE_DOCS list, and TEMPLATE_CONTENT.
IF EXISTS: Load .specify/memory/constitution.md for project principles and governance constraints.
Clarify intent (dynamic): Derive up to THREE initial contextual clarifying questions (no pre-baked catalog). They MUST:
$ARGUMENTSGeneration algorithm:
Question formatting rules:
Defaults when interaction impossible:
Output the questions (label Q1/Q2/Q3). After answers: if ≥2 scenario classes (Alternate / Exception / Recovery / Non-Functional domain) remain unclear, you MAY ask up to TWO more targeted follow‑ups (Q4/Q5) with a one-line justification each (e.g., "Unresolved recovery path risk"). Do not exceed five total questions. Skip escalation if user explicitly declines more.
Understand user request: Combine $ARGUMENTS + clarifying answers:
Load feature context: Read from FEATURE_DIR:
Context Loading Strategy:
Generate checklist - Use TEMPLATE_CONTENT as the structural template and create "Unit Tests for Requirements":
FEATURE_DIR/checklists/ directory if it doesn't existux.md, api.md, security.md)[domain].md[ ]); checkbox state belongs to the reviewerCORE PRINCIPLE - Test the Requirements, Not the Implementation: Every checklist item MUST evaluate the REQUIREMENTS THEMSELVES for:
Category Structure - Group items by requirement quality dimensions:
HOW TO WRITE CHECKLIST ITEMS - "Unit Tests for English":
❌ WRONG (Testing implementation):
✅ CORRECT (Testing requirements quality):
ITEM STRUCTURE: Each item should follow this pattern:
[Spec §X.Y] when checking existing requirements[Gap] marker when checking for missing requirementsEXAMPLES BY QUALITY DIMENSION:
Completeness:
Clarity:
Consistency:
Coverage:
Measurability:
Scenario Classification & Coverage (Requirements Quality Focus):
Traceability Requirements:
[Spec §X.Y], or use markers: [Gap], [Ambiguity], [Conflict], [Assumption]Surface & Resolve Issues (Requirements Quality Problems): Ask questions about the requirements themselves:
Content Consolidation:
🚫 ABSOLUTELY PROHIBITED - These make it an implementation test, not a requirements test:
✅ REQUIRED PATTERNS - These test requirements quality:
Structure Reference: Generate the checklist following the canonical template in .specify/templates/checklist-template.md for title, meta section, category headings, ownership note, notes section, and ID formatting. If template is unavailable, use: H1 title, purpose/created meta lines, an ownership note explaining that [x] means reviewer approval of requirements quality, ## category sections containing - [ ] CHK### <requirement item> lines with globally incrementing IDs starting at CHK001, and notes that $speckit-implement reads checklist state but does not modify markers.
Report: Output full path to checklist file, item count, and summarize whether the run created a new file or appended to an existing one. Summarize:
Important: Each $speckit-checklist command invocation uses a short, descriptive checklist filename and either creates a new file or appends to an existing one. This allows:
ux.md, test.md, security.md)checklists/ folderTo avoid clutter, use descriptive types and clean up obsolete checklists when done.
UX Requirements Quality: ux.md
Sample items (testing the requirements, NOT the implementation):
API Requirements Quality: api.md
Sample items:
Performance Requirements Quality: performance.md
Sample items:
Security Requirements Quality: security.md
Sample items:
❌ WRONG - These test implementation, not requirements:
- [ ] CHK001 - Verify landing page displays 3 episode cards [Spec §FR-001]
- [ ] CHK002 - Test hover states work correctly on desktop [Spec §FR-003]
- [ ] CHK003 - Confirm logo click navigates to home page [Spec §FR-010]
- [ ] CHK004 - Check that related episodes section shows 3-5 items [Spec §FR-005]✅ CORRECT - These test requirements quality:
- [ ] CHK001 - Are the number and layout of featured episodes explicitly specified? [Completeness, Spec §FR-001]
- [ ] CHK002 - Are hover state requirements consistently defined for all interactive elements? [Consistency, Spec §FR-003]
- [ ] CHK003 - Are navigation requirements clear for all clickable brand elements? [Clarity, Spec §FR-010]
- [ ] CHK004 - Is the selection criteria for related episodes documented? [Gap, Spec §FR-005]
- [ ] CHK005 - Are loading state requirements defined for asynchronous episode data? [Gap]
- [ ] CHK006 - Can "visual hierarchy" requirements be objectively measured? [Measurability, Spec §FR-001]Key Differences:
Check for extension hooks (after checklist generation):
Check if .specify/extensions.yml exists in the project root.
hooks.after_checklist key.specify/extensions.yml could not be read (include the parser error) and that no hooks were checked, including any mandatory (optional: false) hooks registered there, then continue normallyenabled is explicitly false. Treat hooks without an enabled field as enabled by default.condition expressions:condition field, or it is null/empty, treat the hook as executablecondition, skip the hook and leave condition evaluation to the HookExecutor implementation.) with hyphens (-). For example, speckit.git.commit → $speckit-git-commit.optional flag:optional: true):## Extension Hooks
**Optional Hook**: {extension}
Command: `/{command}`
Description: {description}
Prompt: {prompt}
To execute: `/{command}`optional: false):## Extension Hooks
**Automatic Hook**: {extension}
Executing: `/{command}`
EXECUTE_COMMAND: {command}{command} id shown above, e.g. a skills-mode agent runs it as /skill:speckit-... or $speckit-...). Emitting the block alone does not run the hook..specify/extensions.yml does not exist, skip silently© kunstmusik, GPL-3.0. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file
Just SKILL.md in .agents/skills/speckit-checklist of kunstmusik/blue.
Open the folder on GitHubat commit 3c32d58
We found 20 copies of this SKILL.md (exact, near-identical or edited) in other folders, from 18 other GitHub owners. This page covers the copy in kunstmusik/blue, which our catalogue first saw on October 7, 2026.
Speckit Checklist next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.
| Skill | Stars | Used in | Tokens | Auto-check | Licence | Repo updated |
|---|---|---|---|---|---|---|
| Speckit Checklist this skillkunstmusik/blue | 154 | 18 repos | ~5.6k | Automated safety check: Pass | GPL-3.0 | |
| Backprop: Bug-to-Spec ProtocolJuliusBrussee/cavekit | 1.2k | — | ~653 | Automated safety check: Pass | MIT | |
| Fixgenkovich/sdd | 171 | — | ~2.5k | Automated safety check: Pass | MIT | |
| OpenSpec Bulk Change ArchiverFission-AI/OpenSpec | 72k | 2 repos | ~5.6k | Automated safety check: Pass | MIT | |
| Speckit ConstitutionWeihanLi/WeihanLi.Common | 242 | 12 repos | ~2.1k | Automated safety check: Pass | Apache-2.0 | |
| Review Spdzhu1090093659/spec_driven_develop | 987 | — | ~1.5k | Automated safety check: Pass | MIT |
JuliusBrussee/cavekit
After a bug is found, traces its root cause and feeds a new testable invariant back into the project spec so the bug class can't recur.
genkovich/sdd
A skill your agent uses to fix a reported bug spec-first: reproduce it, trace the symptom to the owning feature's acceptance criteria, pin it with a failing (RED) test, apply the minimal GREEN fix…
Fission-AI/OpenSpec
Archives several completed OpenSpec changes in one operation, checking the codebase to resolve spec conflicts rather than archiving blindly.
WeihanLi/WeihanLi.Common
Create or update the project constitution from interactive or provided principle inputs, ensuring all dependent templates stay in sync.
zhu1090093659/spec_driven_develop
Findings-first code review workflow for AI coding agents. An agent skill from zhu1090093659/spec_driven_develop.
remix-run/react-router
Turns a React Router RFC discussion on GitHub into an implementation, weighing community feedback and settling open questions with you before coding.
kunstmusik/blue
Execute the implementation planning workflow using the plan template to generate design artifacts.
kunstmusik/blue
Create or update the feature specification from a natural language feature description.
kunstmusik/blue
Generate an actionable, dependency-ordered tasks.md for the feature based on available design artifacts.
kunstmusik/blue
Perform a non-destructive cross-artifact consistency and quality analysis across spec.md, plan.md, and tasks.md after task generation.
kunstmusik/blue
A skill your agent uses when writing, reviewing, or committing code to enforce Karpathy's 4 coding principles — surface assumptions before coding, keep it simple, make surgical changes, define…
kunstmusik/blue
Identify underspecified areas in the current feature spec by asking up to 5 highly targeted clarification questions and encoding answers back into the spec.
Categories
Generate a custom checklist for the current feature based on user requirements. Speckit Checklist is an agent skill from kunstmusik/blue. Generate a custom checklist for the current feature based on user requirements.
Speckit Checklist fits situations like: tasks that involve Spec-driven development.
Run `npx skills add kunstmusik/blue --skill speckit-checklist -a claude-code`. Or copy the skill folder (.agents/skills/speckit-checklist in kunstmusik/blue) into .claude/skills/speckit-checklist in your project. Claude Code loads it when a task matches its description.
Run `npx skills add kunstmusik/blue --skill speckit-checklist -a codex`. Or copy the skill folder (.agents/skills/speckit-checklist in kunstmusik/blue) into .agents/skills/speckit-checklist in your project. Codex loads it when a task matches its description.
Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add kunstmusik/blue --skill speckit-checklist -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/speckit-checklist, .gemini/skills/speckit-checklist, .github/skills/speckit-checklist and .opencode/skills/speckit-checklist in your project.
SKILL.md names no scripts, command-line tools or credentials: Speckit Checklist is instructions for the agent only. Compatibility (from SKILL.md): Requires spec-kit project structure with .specify/ directory.
SKILL.md contains no URLs. Any network use would come from the scripts or tools the agent runs. This is read from the text; nothing was executed.
Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.
Speckit Checklist is published under the GPL-3.0 licence (the repository's licence). It allows redistribution, so the full SKILL.md is shown on this page.
About 5.6k tokens (SKILL.md is roughly 23k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full.
Skills that share tags, products or a category with Speckit Checklist: Backprop: Bug-to-Spec Protocol (JuliusBrussee/cavekit, 1.2k stars), Fix (genkovich/sdd, 171 stars), OpenSpec Bulk Change Archiver (Fission-AI/OpenSpec, 72k stars) and Speckit Constitution (WeihanLi/WeihanLi.Common, 242 stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.
kunstmusik (a GitHub user) maintains it in kunstmusik/blue, which has 154 GitHub stars. The repository holds 16 skills in this directory. The repository was last updated on October 8, 2026.
Source: kunstmusik/blue on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.