billing-kit-mcp — diagrams

The mermaid sources for this repo. They live here rather than in the README because npm renders no mermaid: on the package page a fence like this one ships as raw DSL. GitHub and the QuxKit docs site both draw them. The README carries an ASCII equivalent of each.

The server between an MCP host and exact arithmetic

flowchart LR
    host["MCP host<br/>Claude Desktop · Claude Code"]
    subgraph srv["billing-kit-mcp"]
        t["price_usage · format_money<br/>check_ledger_balance<br/>search_api · list_components"]
    end
    bk["billing-kit<br/>Money · Quantity · Rate · price"]
    host <-->|stdio · JSON-RPC| srv
    t -->|exact arithmetic| bk
    classDef a fill:#0d9488,stroke:#0f766e,color:#fff
    class bk a

Why the tool exists: an assistant guessing vs. the Money type

flowchart TB
    q["price 1,234,567 tokens<br/>at $0.0000012 / token, USD"]
    q --> guess["assistant on its own<br/>invents qty × rate ÷ 100<br/>drifts on large values,<br/>wrong for a third of ISO 4217"]
    q --> tool["price_usage → billing-kit<br/>$1.48 · exact 148.14804 minor<br/>from the Money type"]
    classDef bad fill:#9e2b2b,stroke:#7f2222,color:#fff
    classDef good fill:#2c6e5b,stroke:#225646,color:#fff
    class guess bad
    class tool good