XanoScript Docs Expert

Overview

This skill provides expert-level knowledge for working with the xanoscriptdocs system inside the @xano/developer-mcp project. The project is a dual-purpose npm package: an MCP Server that serves XanoScript documentation to AI assistants, and a standalone library. The documentation lives as markdown files in src/xanoscriptdocs/ and is the primary content delivered by the xanoscript_docs MCP tool.

Architecture at a Glance

src/
├── index.ts                    # MCP server entry (stdio transport)
├── lib.ts                      # Library entry (standalone usage)
├── xanoscript.ts               # Core doc logic: topic registry, file matching, content extraction
├── tools/
│   ├── index.ts                # Tool registry + dispatch (6 tools total)
│   ├── xanoscript_docs.ts      # xanoscript_docs tool: path resolution, MCP definition
│   ├── validate_xanoscript.ts  # Code validation via language server parser
│   ├── meta_api_docs.ts        # Meta API docs tool
│   ├── run_api_docs.ts         # Run API docs tool
│   ├── cli_docs.ts             # CLI docs tool
│   ├── mcp_version.ts          # Version tool
│   └── types.ts                # Shared ToolResult type
├── xanoscript_docs/            # 34 documentation topics (THE CONTENT)
│   ├── README.md               # Overview (topic="readme"; previously the no-args default)
│   ├── version.json            # { "version": "2.0.0", "updated": "2025-02-06" }
│   ├── docs_index.json         # Machine-readable index with aliases, filters, constructs
│   ├── cheatsheet.md, syntax.md, quickstart.md, types.md  # Core language docs
│   ├── functions.md, database.md, tables.md, apis.md      # Construct-specific docs
│   ├── agents.md, tools.md, mcp-servers.md, triggers.md   # AI & event docs
│   ├── [16 more topic files...]
│   └── integrations/           # Sub-topic directory
│       ├── cloud-storage.md, search.md, redis.md
│       ├── external-apis.md, utilities.md
│   ...
├── meta_api_docs/              # Separate doc module for Meta API
├── run_api_docs/               # Separate doc module for Run API
└── cli_docs/                   # Separate doc module for CLI

How the xanoscript_docs Tool Works

Request Flow

Caller provides { topic?, file_path?, mode?, tier?, max_tokens?, exclude_topics? }
    │
    ├── tier="survival"|"working" → Return the pre-built tier digest (overrides everything)
    ├── mode="index" OR no topic/file_path → Return the compact topic index (~4KB)
    │       (the no-arg default; README is reachable via topic="readme")
    ├── topic="syntax" → Return syntax.md content
    ├── file_path="api/users/create.xs" → minimatch applyTo patterns → return all matching docs
    └── mode="quick_reference" → Extract only "## Quick Reference" sections
    │
    └── All responses append: "---\nDocumentation version: X.X.X"

Key Source Files

src/xanoscript.ts — The brain of the system:

• XANOSCRIPTDOCSV2: Record<string, DocConfig> mapping 34 topic keys to { file, applyTo, description }
• getDocsForFilePath(filePath): Uses minimatch to match file paths against applyTo glob patterns. Always includes "syntax" as a foundation topic.
• extractQuickReference(content, topic): Finds "## Quick Reference" heading and extracts content until the next ## heading. Falls back to first 50 lines.
• readXanoscriptDocsV2(docsPath, args): Main read function — decides what to return based on args.

src/tools/xanoscript_docs.ts — The tool wrapper:

• getXanoscriptDocsPath(): Resolves docs directory — tries dist/xanoscriptdocs/ first, falls back to src/xanoscriptdocs/.
• xanoscriptDocs(args): Standalone function returning { documentation: string }.
• xanoscriptDocsTool(args): Returns ToolResult ({ success, data?, error? }).
• xanoscriptDocsToolSpec: Built via defineTool({ inputShape, outputShape, ... }) — the Zod shapes are the single source of truth, and xanoscriptDocsToolSpec.definition exposes the derived JSON Schema for clients.

src/tools/index.ts — Registration:

• toolSpecs map (5 tools) is the single source of truth used by McpServer.registerTool in src/index.ts
• handleTool(name, args) is async and dispatches via a typed dispatch table keyed off toolSpecs — adding to toolSpecs without a handler is a compile error
• toMcpResponse() converts ToolResult to MCP format: { content: [{ type: "text", text }], isError? }

Build Process

tsc && cp -r src/xanoscript_docs dist/

TypeScript compiles to dist/, then markdown files are copied verbatim. The docs are NOT transformed — they ship as-is.

Adding a New Documentation Topic

This is the most common modification. Follow these steps exactly:

Step 1: Create the Markdown File

Create a new .md file in src/xanoscript_docs/. For sub-topics, use the integrations/ subdirectory pattern.

Every doc file MUST start with frontmatter:

---
applyTo: "function/*.xs, api/**/*.xs"
---

The applyTo value specifies which file patterns this doc applies to when using context-aware delivery. Use empty string or omit patterns for docs only accessible via explicit topic parameter.

Step 2: Register the Topic in src/xanoscript.ts

Add an entry to the XANOSCRIPTDOCSV2 object:

"my-new-topic": {
  file: "my-new-topic.md",           // Path relative to xanoscript_docs/
  applyTo: ["function/**/*.xs"],        // Glob patterns for context-aware matching
  description: "One-line description of what this doc covers",
},

For sub-topics in a directory:

"integrations/my-service": {
  file: "integrations/my-service.md",
  applyTo: [],                        // Sub-topics typically have empty applyTo
  description: "Description here",
},

Step 3: Update docs_index.json (Optional but Recommended)

Add the topic to src/xanoscriptdocs/docsindex.json in the appropriate section:

"my-new-topic": {
  "file": "my-new-topic.md",
  "purpose": "Brief purpose description",
  "aliases": ["alias1", "alias2"]
}

Also update constructs, operations, or tasks sections if the new topic documents any of those.

Step 4: Bump Version

Update src/xanoscript_docs/version.json:

{
  "version": "2.1.0",
  "updated": "2025-03-15"
}

Step 5: Build and Test

npm run build    # tsc && cp -r src/xanoscript_docs dist/
npm test         # vitest run

Documentation Authoring Conventions

Read references/doc-conventions.md for the complete style guide. Here's the essential pattern:

Required Structure

Every documentation file follows this skeleton:

---
applyTo: "pattern/**/*.xs"
---

# Topic Title

> **TL;DR:** One or two sentences summarizing the key concepts.

## Quick Reference

| Feature | Example | Notes |
|---------|---------|-------|
| ...     | ...     | ...   |

## [Detailed Sections]

### Basic Structure
[Minimal working example]

### Common Patterns
[Real-world usage examples]

### Common Mistakes

❌ **Wrong:**

// incorrect code

✅ **Correct:**

// correct code

## Related Topics

| Topic | Use For |
|-------|---------|
| [syntax](xano_xanoscript_docs({ topic: "syntax" })) | Filters and operators |

Code Examples

• Use xs language identifier for XanoScript code blocks
• Use javascript for frontend code, json for data
• Comments use // only (no # or / / in XanoScript)
• Show both wrong and correct patterns with ❌/✅ markers
• Progress from simple to complex examples

Cross-Referencing

Reference other topics using this pattern:

For details, see xano_xanoscript_docs({ topic: "syntax" })
For sub-topics: xano_xanoscript_docs({ topic: "integrations/redis" })

File Naming

• Lowercase with hyphens: unit-testing.md, cloud-storage.md
• Integration sub-topics go in integrations/ subdirectory

XanoScript Language Reference

For quick reference when writing docs, see references/xanoscript-language.md. Key things to remember:

Type Names (Common Mistake Area)

Filter Type Safety (Most Common Doc Error)

String filters and array filters are NOT interchangeable. This is the #1 source of mistakes in the docs:

Control Flow Keyword

Always elseif (one word), never else if.

String Concatenation

Use ~ (tilde), not +. Parentheses required around filtered values in concatenation:

($count|to_text) ~ " items"

Modifying the MCP Tool Itself

For changes to how documentation is served (not the content):

Changing Tool Parameters

Edit xanoscriptDocsToolSpec in src/tools/xanoscript_docs.ts. Parameters live in the Zod inputShape (with .describe() for docs); the JSON Schema sent to MCP clients is derived automatically via z.toJSONSchema.

Changing Doc Resolution Logic

Edit functions in src/xanoscript.ts:

• getDocsForFilePath() — context-aware matching logic
• extractQuickReference() — quick reference extraction
• readXanoscriptDocsV2() — main read dispatch

Changing Path Resolution

Edit getXanoscriptDocsPath() in src/tools/xanoscriptdocs.ts. The fallback chain: dist/xanoscriptdocs/ → src/xanoscript_docs/ → default.

Adding a New MCP Tool

1. Create src/tools/mytool.ts — build the spec with defineTool({ name: "xanomy_tool", inputShape, outputShape, ... }) and export the handler
2. Register in src/tools/index.ts: add to the toolSpecs map and the typed dispatch table (TypeScript will fail to compile if you forget the handler)
3. Export from src/lib.ts if needed for standalone usage

Testing

npm test                    # Run all tests
npm run test:watch          # Watch mode
npm run test:coverage       # With V8 coverage

Test files live alongside source: src/xanoscript.test.ts. Tests use Vitest with describe/it/expect patterns.

Key things to test when modifying docs:

• New topics resolve correctly via readXanoscriptDocsV2({ topic: "new-topic" })
• applyTo patterns match expected file paths via getDocsForFilePath()
• Quick reference extraction works if your doc has a ## Quick Reference section

Common Tasks Checklist