| name | doncheli-distill |
| description | Extract behavioral specifications and architecture diagrams from existing code (Blueprint Distillation / reverse engineering). Activate when user mentions "distill", "reverse engineer", "extract spec", "blueprint distillation", "understand codebase", "document existing code". |
Don Cheli: Blueprint Distillation
Instructions
- Identify the target module, service or codebase to distill
- Scan entry points (routes, controllers, event handlers, CLI commands)
- Trace data flows: inputs → transformations → outputs → side effects
- Identify implicit business rules embedded in conditionals, validations, error handling
- Map entity relationships from data models and DB schemas
- Generate Gherkin scenarios that describe the observed behavior (not the code)
- Produce a C4-style architecture diagram in text (Mermaid or ASCII)
- Flag ambiguities, dead code, and undocumented assumptions with
[NEEDS CLARIFICATION]
Output Format
## Blueprint: <module/service name>
### Architecture Diagram
```mermaid
…
Distilled Spec (Gherkin)
Feature: <name>
Background: …
Scenario: <happy path>
Given …
When …
Then …
Scenario: <edge case / sad path>
…
Implicit Business Rules
- — found in: file:line
…
Ambiguities & Dead Code
## Quality Gate
- Every entry point must map to at least one Gherkin scenario
- Architecture diagram must show at least: external inputs, internal modules, data stores, external services
- Business rules must cite their source location
## Do not use this skill when
- The user wants to write new specs for a new feature (use doncheli-spec instead)
- The codebase has no existing logic to analyze
