Agent Skills: Generate UML Diagram

Generate UML Diagram

Produce a Mermaid diagram that documents system structure or behavior. Output goes to .orchestra/uml/.

Diagram Types

Choose the type that matches what you're documenting:

| Type | Use When | Mermaid Block | |------|----------|---------------| | sequence | Agent-to-tool flows, multi-step workflows, API call chains | sequenceDiagram | | class | Data models, object relationships, schema structure | classDiagram | | deployment | On-device vs cloud allocation, infrastructure topology | graph TB with subgraphs | | component | High-level system overview, major pieces and connections | graph LR | | state | Workflow states, agent decision logic, valid transitions | stateDiagram-v2 |

Steps

1. Identify the Diagram Type

Read $ARGUMENTS. If no type is given, ask:

• Is this about the flow of an interaction? → sequence
• Is this about data shape or relationships? → class
• Is this about where things run? → deployment
• Is this about what the major pieces are? → component
• Is this about states and transitions? → state

2. Gather Context

• Glob relevant source files, skill definitions, or agent configs
• Read existing .orchestra/uml/ diagrams to avoid duplication and match style
• Read the active milestone PRD for scope

3. Generate the Diagram

Use the appropriate Mermaid syntax:

Sequence:

sequenceDiagram
    participant A as Agent
    participant T as Tool / MCP Server
    participant API as External API
    A->>T: tool call with params
    T->>API: downstream request
    API-->>T: response
    T-->>A: structured result

Class:

classDiagram
    class Artifact {
        +String ticket
        +String status
        +Date created_on
    }
    class PRD {
        +String objective
        +List criteria
    }
    Artifact <|-- PRD

Deployment:

graph TB
    subgraph Device["On-Device"]
        App["App"]
        Model["Local Model"]
    end
    subgraph Cloud["Cloud"]
        Worker["Cloudflare Worker"]
        DB["D1 Database"]
    end
    App -->|inference| Model
    App -->|API call| Worker
    Worker -->|query| DB

Component:

graph LR
    A["Component A"]
    B["Component B"]
    C["Component C"]
    A -->|action| B
    B -->|result| C

State:

stateDiagram-v2
    [*] --> Draft
    Draft --> Approved
    Approved --> InProgress
    InProgress --> Complete
    Complete --> [*]

4. Write the File

Save to .orchestra/uml/{project}-{type}-{purpose}.md

Naming convention: [project]-[diagram-type]-[purpose].md

• chiropractic-sequence-soap-pipeline.md
• orchestra-component-plugin-structure.md
• kairos-state-daily-rhythm.md

Include frontmatter per ADR-001 (UML carries created_on only — no status, no ticket):

---
created_on: {YYYY-MM-DD}
---

Full file structure:

---
created_on: YYYY-MM-DD
---

# {Diagram Title}

> {One sentence: what this diagram shows and why it exists}

```mermaid
{diagram code}

Notes

{Optional: call out non-obvious decisions, constraints, or what to look at first}

References

• {Spec, ADR, or external doc this diagram relates to}

### 5. Cross-Reference

If this diagram was prompted by a spec or ADR, add a reference line to that document pointing back to the diagram. The relationship is:
- **Specs** document *what* — reference the UML for *how*
- **ADRs** document *why* — reference the UML for the topology that resulted from the decision

## Examples

See `examples/` for reference diagrams:

| File | Type | What It Shows |
|------|------|---------------|
| `examples/sequence.md` | sequence | Multi-phase agent workflow with parallel tool calls and retry logic |

## Quality Checks

- [ ] Diagram type matches what's being shown (don't use sequence for topology)
- [ ] Participants and nodes have human-readable labels, not code identifiers
- [ ] Mermaid syntax is valid — no unclosed blocks, correct arrow types
- [ ] Filename follows `[project]-[type]-[purpose].md` convention
- [ ] `created_on` frontmatter is present
- [ ] One sentence description is present below the title