Agentic Mermaid

Author a new Mermaid diagram from blank by folding a list of structured ops over an empty diagram of `family`. The declarative counterpart to hand-writing source. Returns the same envelope as `mutate`: { ok, family, source, verify } or { ok:false, family, opIndex, error }. Call `describe_sdk` for the family before authoring unfamiliar ops.

Run JavaScript in an isolated sandbox; return a value. One call composes edits. Submit JavaScript; declaration types are guidance. No promises, async/await, dynamic import, or type annotations. Hosted note: execute runs in an on-demand isolate and costs more than the direct render_svg/render_ascii/render_png/verify/describe tools — prefer those for plain render/verify calls. For straightforward structured edits, prefer the declarative mutate/build tools; reserve execute for logic the ops don't express. Hosted mermaid.renderMermaidSVG*, renderMermaidASCII*, and layoutMermaidWithReceipt calls force security:'strict' and embedFontImport:false; caller code cannot weaken that host policy. SDK declaration: type DiagramKind = 'flowchart' | 'state' | 'sequence' | 'timeline' | 'class' | 'er' | 'journey' | 'architecture' | 'xychart' | 'pie' | 'quadrant' | 'gantt' | 'mindmap' | 'gitgraph' | 'radar' type MutationOp = { kind: string; [field: string]: unknown } type Result<T, E = { code: string; message: string }> = { ok: true; value: T } | { ok: false; error: E } interface SourceLocation { readonly line: number; readonly col: number } interface SourceMapSpans { readonly preserved: PreservedSourceSpans; readonly nodes: ReadonlyMap<string, SourceSpan>; readonly edges: ReadonlyMap<string, SourceSpan>; readonly groups: ReadonlyMap<string, SourceSpan>; readonly labels: ReadonlyMap<string, SourceSpan> } interface SourceMap { readonly nodes: ReadonlyMap<string, SourceLocation>; readonly edges: ReadonlyMap<string, SourceLocation>; readonly groups: ReadonlyMap<string, SourceLocation>; readonly labels: ReadonlyMap<string, SourceLocation>; readonly spans?: SourceMapSpans } interface ValidDiagram { readonly kind: DiagramKind; readonly source: SourceMap } type ExternalFamilyId = `family:${string}` interface ExtensionCompatibility { readonly [contract: string]: string | undefined readonly core?: string readonly scene?: string } interface ExtensionProvenance { readonly owner: string; readonly source: string; readonly reference?: string } interface ExtensionIdentity<Kind extends string = string> { readonly id: `${Kind}:${string}` readonly kind: Kind readonly version: string readonly compatibility: ExtensionCompatibility readonly provenance: ExtensionProvenance } interface SourceSpanPoint { readonly offset: number; readonly line: number; readonly col: number } interface SourceSpan { readonly start: SourceSpanPoint; readonly end: SourceSpanPoint } interface PreservedSourceSpans { readonly source: SourceSpan readonly wrapper?: SourceSpan readonly frontmatter?: SourceSpan readonly initDirectives?: readonly SourceSpan[] readonly accessibilityDirectives?: readonly SourceSpan[] readonly header: SourceSpan readonly body: SourceSpan } interface SourcePreservationReceipt { readonly version: 1 readonly classification: 'unsupported' | 'inventory-only' | 'unknown' readonly source: string readonly header: string readonly upstreamFamilyId?: string readonly mermaidVersion: string readonly spans?: PreservedSourceSpans } interface ParseError { readonly code: string readonly message: string readonly line?: number readonly col?: number readonly preservation?: SourcePreservationReceipt readonly help?: string } interface ExtensionValidDiagram { readonly kind: ExternalFamilyId readonly descriptorIdentity: ExtensionIdentity<'family'> readonly source: SourceMap } interface PreservedValidDiagram { readonly kind: ExternalFamilyId readonly source: SourceMap readonly body: { readonly kind: 'preserved' readonly representation: 'opaque' | 'unknown' readonly source: string readonly preservation: SourcePreservationReceipt readonly spans: PreservedSourceSpans readonly diagnostic: { readonly code: 'UNSUPPORTED_FAMILY' | 'UNKNOWN_HEADER' | 'FAMILY_DESCRIPTOR_MISMATCH' readonly message: string readonly help: string } } } type ParsedDiagram = ValidDiagram | ExtensionValidDiagram | PreservedValidDiagram type RenderedRegionKind='node'|'edge'|'label'|'canvas'|'group'|'cluster'|'lane'|'band'|'compartment'|'plot'|'ring' type DiagramActionSecurity='safe'|'unsafe'|'source-only'|'unsupported' interface RenderedRegion { id:string;kind:RenderedRegionKind;elementId?:string;parentId?:string;bounds:{x:number;y:number;w:number;h:number};sourceLine?:number } interface DiagramActionRecord { id?:string;regionId?:string;family:DiagramKind;target:string;action:'href'|'call'|'callback';raw:string;line?:number;href?:string;security:DiagramActionSecurity;executable:false;message?:string } interface RenderedLayout { version: 1; kind: DiagramKind | ExternalFamilyId; bounds: { w: number; h: number }; nodes: unknown[]; edges: unknown[]; groups: unknown[]; regions?: RenderedRegion[]; actions?: DiagramActionRecord[] } interface VerifyResult { ok: boolean; warnings: unknown[]; layout: RenderedLayout } type CheckMermaidSpec = string[] | { include?: string[]; exclude?: string[]; exact?: boolean } interface CheckMermaidResult { ok: boolean; missing: string[]; unexpected: string[]; facts: string[] } type MermaidConfigScalar = string | number | boolean | null type MermaidConfigValue = MermaidConfigScalar | MermaidConfigValue[] | { [key: string]: MermaidConfigValue | undefined } type MermaidRuntimeConfig = { [key: string]: MermaidConfigValue | undefined } interface StyleColors {bg?:string;fg?:string;line?:string;accent?:string;muted?:string;surface?:string;border?:string} type SceneStyleRole="node"|"edge"|"edge-label"|"group"|"group-header"|"label"|"actor"|"lifeline"|"activation"|"message"|"block"|"note"|"class-box"|"member"|"entity"|"attribute"|"relationship"|"cardinality"|"pie-slice"|"legend"|"bar"|"series"|"point"|"axis"|"grid"|"plate"|"section"|"task"|"milestone"|"marker-line"|"rail"|"period"|"event"|"score"|"actor-pill"|"service"|"junction"|"icon"|"title"|"defs"|"prelude"|"chrome" type ExactSceneStyleRole="node"|"edge"|"group"|"group-header"|"label"|"actor"|"relation… [8965 more characters not shown]

Apply a list of structured edit ops to an existing Mermaid `source` and return the edited diagram. This is the declarative counterpart to `execute`: plain JSON in, plain JSON out, no sandbox. Prefer it for straightforward edits; reserve `execute` for logic the ops don't express. Returns { ok, family, source, verify:{ ok, warnings } } on success, or { ok:false, family, opIndex, error } — where `error` names the offending field and lists the valid ones — when an op is malformed or cannot apply. Ops apply in order and are all-or-nothing: the first failing op stops the batch (its position is `opIndex`) and the input is left untouched. Each op is { "kind": <op>, …fields }. Call `describe_sdk` for the detected family before authoring unfamiliar ops; it returns compact signatures or exact field types, enum values, defaults, and constraints.

Render a Mermaid source string to text. Returns { ok, text }. useAscii true → plain ASCII (+,-,|); false/absent → Unicode box drawing (┌,─,│). targetWidth sets a hard terminal display-cell bound; impossible bounds return a typed error.

Rasterize a Mermaid source string to PNG. Returns { ok, png_base64 }. Hosted rendering uses resvg-wasm with bundled fonts; bytes may differ from the local napi renderer, so hosted PNG is a convenience surface, not part of the byte-determinism contract. For file/URL artifacts use the local stdio server.

Render a Mermaid source string to themeable SVG. Returns { ok, svg }. Layout is deterministic: identical input produces identical geometry. The hosted boundary forces security:'strict' and embedFontImport:false.

Parse and verify a Mermaid diagram without rendering it. Returns { ok, family, summary, warnings, layout: { bounds, nodes, edges } } for valid diagrams and { ok: false, errors } for parse failures. `family` is the detected diagram family and `summary` a one-line description — check them: ok:true only means the diagram is structurally valid, not that it is the kind you intended. Warnings use the layout-rubric codes.

Describe a Mermaid diagram. format=text returns { ok, text } with one or two summary sentences; format=json returns { ok, tree } with the AX tree; format=facts returns { ok, facts } with deterministic semantic fact lines for machine checking (for example edge A -> B : label, member Duck +quack()).

Return version-matched mutation operations for one diagram family. Use detail=signatures for the compact op menu or detail=fields (default) for exact field types, required flags, enum values, defaults, and constraints. Call this before build, mutate, or execute when the family schema is not already known.