# `ConduitMcp.Validation`
[🔗](https://github.com/nyo16/conduit_mcp/blob/v0.9.3/lib/conduit_mcp/validation.ex#L1)

Runtime parameter validation using NimbleOptions.

This module provides runtime parameter validation for MCP tools,
prompts, and resources using NimbleOptions schemas. It works alongside
the existing JSON Schema generation to provide both client-side
validation (JSON Schema) and server-side validation (NimbleOptions).

## Features

- Runtime parameter validation with detailed error messages
- Type coercion (string "123" -> integer 123)
- Advanced constraints (min/max, length limits)
- Custom validator functions
- Compile-time schema generation for performance

## Configuration

Validation behavior can be configured in your application config:

    config :conduit_mcp, :validation,
      runtime_validation: true,           # Enable/disable validation
      strict_mode: true,                  # Fail on errors vs. log and continue
      type_coercion: true,                # Automatic type conversion
      log_validation_errors: false        # Log validation failures

# `format_validation_errors`

Formats validation errors into a standardized format for JSON-RPC responses.

Takes NimbleOptions validation errors and converts them to a format
suitable for MCP error responses.

## Examples

    iex> errors = [%{parameter: "age", value: -5, message: "must be >= 0"}]
    iex> ConduitMcp.Validation.format_validation_errors(errors)
    [%{"parameter" => "age", "value" => -5, "message" => "must be >= 0"}]

# `update_validation_config`

Updates the validation configuration at runtime.

Writes to both Application env and persistent_term so that
the change is visible immediately to all concurrent readers.

# `validate_prompt_args`

Validates prompt arguments using the compiled NimbleOptions schema.

Similar to `validate_tool_params/3` but for prompt arguments.

# `validate_tool_params`

Validates tool parameters using the compiled NimbleOptions schema.

Returns `{:ok, validated_params}` with potentially coerced types,
or `{:error, validation_errors}` with detailed error information.

## Examples

    iex> ConduitMcp.Validation.validate_tool_params(MyServer, "greet", %{"name" => "Alice"})
    {:ok, %{"name" => "Alice"}}

    iex> ConduitMcp.Validation.validate_tool_params(MyServer, "calc", %{"age" => "-5"})
    {:error, [%{parameter: "age", value: -5, message: "must be greater than or equal to 0"}]}

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*Consult [api-reference.md](api-reference.md) for complete listing*