A server which supports the &tos; protocol announces support via both stream features and &xep0030;.

The interaction with the Terms of Service is handled using &xep0050;.

To request the current Terms of Service and Opt-ins/Opt-outs, the client starts an Ad-Hoc command session with the 'urn:xmpp:tos:0' node at its server:

The client MUST include a <tos-support/> child in the initial request to inform the server that it fully supports the protocol. A server MAY reject the Ad-Hoc command from a client which does not fully support the protocol if the form would likely not render correctly or completely. In that case, a <not-acceptable/> type='cancel' error MUST be returned.

The server SHOULD use the value of xml:lang at the <command/> element to determine the language of returned texts.

If the server allows the request, it starts the command session and returns the payload:

The command payload consists of two parts: The data form for legacy clients and additional opt-ins/opt-outs, and the machine-readable &tos; data. The machine-readable &tos; data is carried by a <tos/> element.

The <tos/> element has the following format:

version attribute

(exactly once) carries the opaque version identifier of the terms.

<document/> element

(at least once) carries one of the possibly multiple documents which comprise the full terms of use (see below for details).

<required-flags/> element

(at most once) carries a set of data form field var values which the user has to accept (set to true) in order to use the service.

In the future, more children may be added to the <tos/> element. Conforming clients thus MUST ignore all children they do not understand.

The <document/> element has the following format:

<title/> element

(at most once) a human-readable title of the document in the language requested by the client.

<source/> element

(at least once) a pair of url and MIME type. The same URL may be given multiple times with different MIME types. Duplicate MIME types MUST NOT occur.

The <required-flags/> element contains zero or more <required-flag/> elements. The <required-flag/> elements have a var attribute which refers to one of the fields in the data form. Note that this is semantically different from <require/> in the data form (see &xep0004;)

The data form has the FORM_TYPE 'urn:xmpp:tos:0'. The fields 'urn:xmpp:tos:0#version' and 'urn:xmpp:tos:0#documents' are mandatory. If the value of the 'urn:xmpp:tos:0#version' data form field and the version attribute of the <tos/> element differ, the response is invalid.

The data form MAY contain arbitrary fields after the 'urn:xmpp:tos:0#documents' field.

A client supporting the &tos; protocol should remove the fields prefixed with 'urn:xmpp:tos:0#' from the form when displaying the form and use a richer representation obtained from the <tos/> element for the same data.

The 'urn:xmpp:tos:0#documents' MUST contain exactly one URL from each <document/> advertised in the <tos/> element. It is used to inform users of legacy clients of the terms.

The server MAY include <instruction/> and <title/> elements in the data form.

Once the user has filled out the form, the client submits it to the server:

The client does not include the <tos/> element in its response.

The server acknowledges the reception as usual:

If a server updates its &tos;, it may inform its users with a notification. For this, a 'headline' <message/> is used:

The <body/> is included for clients not supporting the protocol. The user can then review the Terms of Service by themselves. In addition to the <body/>, a <tos-push/> element which contains the <tos/> element of the new terms and an optional <deadline/> element.

The <deadline/> element includes a &xep0082; DateTime value which indicates at which point in time the user must have agreed to the new &tos; to be allowed to continue to use the service.

If a user does not agree to an update of the &tos;, a service may lock down the account. In this case, authentication is handled as normal. In the post-authentication stream features, the server then MUST include a <tos/> element with a <agreement-required/> child:

If the <agreement-required/> element is included in the <tos/> stream feature, the client must first agree to the &tos; as described in Interact with Terms of Service.