Vapora/schemas

VAPORA Validation Schemas

Nickel schemas for runtime validation of MCP tools and agent tasks.

Directory Structure

schemas/
├── tools/              # MCP tool parameter validation
│   ├── kanban_create_task.ncl
│   ├── kanban_update_task.ncl
│   ├── assign_task_to_agent.ncl
│   ├── get_project_summary.ncl
│   └── get_agent_capabilities.ncl
│
└── agents/             # Agent task assignment validation
    └── task_assignment.ncl

Schema Format

Nickel schemas define:

• Field types (String, Number, Bool, Array, Object)
• Required/optional fields (via default values)
• Validation contracts (NonEmpty, Email, UUID, Range, Pattern, etc.)
• Documentation (via doc annotations)

Example

{
  tool_name = "example_tool",

  parameters = {
    # Required field with contracts
    user_id
      | String
      | doc "User UUID"
      | std.string.NonEmpty
      | std.string.match "^[0-9a-f]{8}-[0-9a-f]{4}-...$",

    # Optional field with default
    priority
      | Number
      | doc "Priority score (0-100)"
      | std.number.between 0 100
      | default = 50,
  },
}

Supported Contracts

Contract	Description	Example
std.string.NonEmpty	String cannot be empty	Required text fields
std.string.length.min N	Minimum length	min 3 for titles
std.string.length.max N	Maximum length	max 200 for titles
std.string.match PATTERN	Regex validation	UUID format
std.number.between A B	Numeric range	between 0 100
std.number.greater_than N	Minimum value (exclusive)	> -1
std.number.less_than N	Maximum value (exclusive)	< 1000
std.string.Email	Email format	user@example.com
std.string.Url	URL format	https://...
std.string.Uuid	UUID format	xxxxxxxx-xxxx-...
std.enum.TaggedUnion	Enum validation	`[

Usage

Schemas are loaded by ValidationPipeline at runtime:

use vapora_shared::validation::{SchemaRegistry, ValidationPipeline};

let registry = Arc::new(SchemaRegistry::new(PathBuf::from("schemas")));
let pipeline = ValidationPipeline::new(registry);

// Validate MCP tool input
let result = pipeline.validate("tools/kanban_create_task", &input).await?;

if !result.valid {
    return (StatusCode::BAD_REQUEST, Json(result.errors));
}

Testing Schemas

Validate schema syntax:

nickel typecheck schemas/tools/kanban_create_task.ncl

Export schema as JSON:

nickel export schemas/tools/kanban_create_task.ncl

Query specific field:

nickel query --field parameters.title schemas/tools/kanban_create_task.ncl

Adding New Schemas

1. Create .ncl file in appropriate directory
2. Define tool_name or schema_name
3. Define parameters or fields with types and contracts
4. Add doc annotations for documentation
5. Test with nickel typecheck
6. Restart services to reload schemas (or use hot-reload)

Hot Reload

Invalidate cached schema without restart:

registry.invalidate("tools/kanban_create_task").await;

Invalidate all schemas:

registry.invalidate_all().await;