Spec Kit Baseline Skill
When to Use
- You need a spec for existing or legacy code.
- You want to document a feature before refactoring.
- You inherited a codebase without written requirements.
Inputs
- A target path, file list, or glob pattern describing the code to analyze.
- Repo context with
.specify/ scripts and templates.
If the target is missing or ambiguous, ask a focused question before continuing.
Goal
Generate a technology-agnostic spec for existing code, then create the feature branch/spec file using the standard Spec Kit templates.
Workflow
Parse target input: Identify files, directories, or patterns to analyze.
- Accept file paths, glob patterns, or directory paths.
- If empty: stop and ask for a concrete target.
Discover and read source files:
- Expand globs to a file list.
- Read file contents for analysis.
- Identify primary language(s) and frameworks.
- Map key file relationships and dependencies.
Analyze code structure:
- Identify entry points and public interfaces.
- Extract function/method signatures and behaviors.
- Find data models and entities.
- Detect API endpoints and routes.
- Identify user-facing functionality.
Generate a short name (2-4 words) from the analyzed code:
- Use action-noun format (e.g., "user-auth", "payment-processing").
- Base on primary functionality discovered.
- Preserve technical terms where meaningful.
Create the feature branch and spec file:
- Find the highest existing feature number for this short name (branches/specs).
- Run
.specify/scripts/bash/create-new-feature.sh --json with the calculated number and short name.
- Read BRANCH_NAME, FEATURE_DIR, and SPEC_FILE paths from the script JSON output.
- For single quotes in args like "I'm Groot", use escape syntax: e.g 'I'''m Groot' (or double-quote if possible: "I'm Groot").
Load the spec template from .specify/templates/spec-template.md.
Draft the specification using the template structure:
- User Stories: Infer from user-facing code paths and interactions.
- Acceptance Scenarios: Derive from validation logic, error handling, and tests.
- Functional Requirements: Extract from business rules and constraints.
- Key Entities: Identify from data models and schemas.
- Success Criteria: Infer from metrics, logging, or performance-related code.
- Assumptions: Document inferences made during analysis.
Abstract implementation details:
- Convert technical patterns to user-focused requirements.
- Remove framework-specific terminology.
- Focus on WHAT the code does, not HOW it does it.
Create spec quality checklist at FEATURE_DIR/checklists/requirements.md.
Report completion with:
- Branch name and spec file path.
- Summary of analyzed files.
- Key features discovered.
- Areas needing clarification or review.
Outputs
specs/<feature>/spec.md
specs/<feature>/checklists/requirements.md
Key rules
- Focus on extracting WHAT and WHY from HOW.
- Abstract away implementation details in the generated spec.
- Document assumptions made during code analysis.
- Flag areas where code behavior is unclear.
- Preserve discovered business rules and constraints.
- Use
[NEEDS CLARIFICATION] for ambiguous code sections (max 3).
- Generated specs should be validated by someone who knows the feature.
Examples
Code Pattern → Spec Requirement:
if (user.role === 'admin') → "System MUST restrict action to administrator users"
password.length >= 8 → "Passwords MUST be at least 8 characters"
cache.set(key, value, 3600) → "System MUST cache results for improved performance"
try { ... } catch (e) { notify(e) } → "System MUST notify users when errors occur"
Code Pattern → User Story:
- Login endpoint with OAuth → "As a user, I can sign in using my social account"
- Shopping cart logic → "As a customer, I can add items to my cart for later purchase"
- Report generation → "As an analyst, I can generate reports on system activity"
Next Steps
After generating spec.md:
- Clarify with domain experts using speckit-clarify.
- Plan modernization/refactoring with speckit-plan.
- Compare the generated spec with actual requirements to identify gaps.
1---2name: speckit-baseline3description: Generate feature specifications by analyzing existing source code.4---5
6# Spec Kit Baseline Skill
7
8## When to Use
9
10- You need a spec for existing or legacy code.
11- You want to document a feature before refactoring.
12- You inherited a codebase without written requirements.
13
14## Inputs
15
16- A target path, file list, or glob pattern describing the code to analyze.
17- Repo context with `.specify/` scripts and templates.
18
19If the target is missing or ambiguous, ask a focused question before continuing.
20
21## Goal
22
23Generate a technology-agnostic spec for existing code, then create the feature branch/spec file using the standard Spec Kit templates.
24
25## Workflow
26
271. **Parse target input**: Identify files, directories, or patterns to analyze.
28 - Accept file paths, glob patterns, or directory paths.
29 - If empty: stop and ask for a concrete target.
30
312. **Discover and read source files**:
32 - Expand globs to a file list.
33 - Read file contents for analysis.
34 - Identify primary language(s) and frameworks.
35 - Map key file relationships and dependencies.
36
373. **Analyze code structure**:
38 - Identify entry points and public interfaces.
39 - Extract function/method signatures and behaviors.
40 - Find data models and entities.
41 - Detect API endpoints and routes.
42 - Identify user-facing functionality.
43
444. **Generate a short name** (2-4 words) from the analyzed code:
45 - Use action-noun format (e.g., "user-auth", "payment-processing").
46 - Base on primary functionality discovered.
47 - Preserve technical terms where meaningful.
48
495. **Create the feature branch and spec file**:
50 - Find the highest existing feature number for this short name (branches/specs).
51 - Run `.specify/scripts/bash/create-new-feature.sh --json` with the calculated number and short name.
52 - Read BRANCH_NAME, FEATURE_DIR, and SPEC_FILE paths from the script JSON output.
53 - For single quotes in args like "I'm Groot", use escape syntax: e.g 'I'''m Groot' (or double-quote if possible: "I'm Groot").
54
556. **Load the spec template** from `.specify/templates/spec-template.md`.
56
577. **Draft the specification** using the template structure:
58 - **User Stories**: Infer from user-facing code paths and interactions.
59 - **Acceptance Scenarios**: Derive from validation logic, error handling, and tests.
60 - **Functional Requirements**: Extract from business rules and constraints.
61 - **Key Entities**: Identify from data models and schemas.
62 - **Success Criteria**: Infer from metrics, logging, or performance-related code.
63 - **Assumptions**: Document inferences made during analysis.
64
658. **Abstract implementation details**:
66 - Convert technical patterns to user-focused requirements.
67 - Remove framework-specific terminology.
68 - Focus on WHAT the code does, not HOW it does it.
69
709. **Create spec quality checklist** at `FEATURE_DIR/checklists/requirements.md`.
71
7210. **Report completion** with:
73 - Branch name and spec file path.
74 - Summary of analyzed files.
75 - Key features discovered.
76 - Areas needing clarification or review.
77
78## Outputs
79
80- `specs/<feature>/spec.md`
81- `specs/<feature>/checklists/requirements.md`
82
83## Key rules
84
85- Focus on extracting WHAT and WHY from HOW.
86- Abstract away implementation details in the generated spec.
87- Document assumptions made during code analysis.
88- Flag areas where code behavior is unclear.
89- Preserve discovered business rules and constraints.
90- Use `[NEEDS CLARIFICATION]` for ambiguous code sections (max 3).
91- Generated specs should be validated by someone who knows the feature.
92
93## Examples
94
95**Code Pattern → Spec Requirement**:
96
97- `if (user.role === 'admin')` → "System MUST restrict action to administrator users"
98- `password.length >= 8` → "Passwords MUST be at least 8 characters"
99- `cache.set(key, value, 3600)` → "System MUST cache results for improved performance"
100- `try { ... } catch (e) { notify(e) }` → "System MUST notify users when errors occur"
101
102**Code Pattern → User Story**:
103
104- Login endpoint with OAuth → "As a user, I can sign in using my social account"
105- Shopping cart logic → "As a customer, I can add items to my cart for later purchase"
106- Report generation → "As an analyst, I can generate reports on system activity"
107
108## Next Steps
109
110After generating spec.md:
111
112- **Clarify** with domain experts using speckit-clarify.
113- **Plan** modernization/refactoring with speckit-plan.
114- **Compare** the generated spec with actual requirements to identify gaps.