email_reply
Sends a reply to an existing message, preserving the conversation: the server carries the provider thread id and the In-Reply-To / References headers, so the reply lands in the same thread rather than starting a new one. Quote and subject handling are automatic. Use this instead of email_send_message any time the user is responding to something they received. reply_all defaults to false — confirm before turning it on, because it mails everyone on the original. account_id must be the mailbox holding the message being replied to. This sends immediately; use email_create_draft with in_reply_to_message_id when the user should review first.
Input fields
{
"type": "object",
"properties": {
"account_id": {
"type": "string",
"minLength": 1,
"description": "The connected mailbox to act on, from email_accounts_list. Never guess this value and never reuse one across mailboxes — it selects both the credential and the permission set the call runs under."
},
"message_id": {
"type": "string",
"minLength": 1,
"description": "A message id returned by this server (msg_...), not a provider id."
},
"reply_all": {
"description": "true to include every original recipient. Default false — reply to the sender only. Confirm with the user before setting this on a large thread.",
"anyOf": [
{
"type": "boolean"
},
{
"type": "null"
}
]
},
"text_body": {
"description": "Plain-text body. Prefer this unless HTML is needed.",
"anyOf": [
{
"type": "string"
},
{
"type": "null"
}
]
},
"html_body": {
"description": "HTML body. Supply text_body too so non-HTML clients render something.",
"anyOf": [
{
"type": "string"
},
{
"type": "null"
}
]
},
"attachments": {
"description": "Files to attach. Supply either content_base64 or source_url per item.",
"anyOf": [
{
"type": "array",
"items": {
"type": "object",
"properties": {
"filename": {
"type": "string",
"minLength": 1
},
"content_type": {
"type": "string",
"minLength": 1,
"description": "MIME type, e.g. application/pdf."
},
"content_base64": {
"description": "Base64 content. Use for small files.",
"type": "string"
},
"source_url": {
"description": "URL the server fetches instead of inline content.",
"type": "string"
},
"size_bytes": {
"type": "integer",
"minimum": 0,
"maximum": 9007199254740991
}
},
"required": [
"filename",
"content_type"
]
}
},
{
"type": "null"
}
]
},
"idempotency_key": {
"type": "string",
"minLength": 1,
"description": "A unique value you generate for this attempt, e.g. a UUID. Retrying with the same key returns the original result instead of acting twice. Reusing a key with different arguments is an IDEMPOTENCY_CONFLICT."
}
},
"required": [
"account_id",
"message_id",
"idempotency_key"
]
}Tool behavior
May change provider state. Check the explicit account, required access and provider capabilities before invoking.
Inspect isError and per-account errors. General write tools do not all enforce exact-plan approval. This reference does not certify any current AI client version.
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