validate_email

Validates that a string is a syntactically well-formed email address in local-part@domain format (RFC 5322). Returns a valid flag and, on failure, a human-readable reason explaining the structural problem.

Parameters

Parameter	Type	Required	Description
email	string	Yes	The email address string to validate.

Response

Field	Type	Description
valid	boolean	true if the address is syntactically well-formed, false otherwise.
reason	string | null	Short explanation of why the address is invalid; null when valid.

Examples

Valid address

{
	"email": "user@example.com"
}

Result:

{
	"valid": true,
	"reason": null
}

Invalid address — missing @

{
	"email": "userexample.com"
}

Result:

{
	"valid": false,
	"reason": "Missing '@' separator between local part and domain."
}

Invalid address — no TLD

{
	"email": "user@localhost"
}

Result:

{
	"valid": false,
	"reason": "Domain must contain at least one dot separating labels (e.g. 'example.com')."
}

Errors

Each failure carries a precise code in the response. Argument-schema and server errors are JSON-RPC protocol errors; a rejected value is returned as a tool result with isError: true (so the agent can read the code and self-correct).

An invalid email is not an error — the tool returns valid: false with a reason. Only an ill-formed request or a server fault can fail.

Code	When	Delivered as
invalid_arguments	An argument is missing or the wrong type.	protocol error (invalid_params)
internal_error	An unexpected server error.	protocol error (internal_error)

Notes

• Validation is purely structural — no DNS or MX-record lookup is performed. A syntactically valid address may still be undeliverable.
• Leading and trailing whitespace is ignored before validation.
• The check is case-insensitive (both User@Example.COM and user@example.com are accepted).