Is ritual described in the Pali canon? There are a great many Buddhist rituals which vary across Buddhist schools and traditions. Did the Buddha describe any rituals which were  to be done as part of practice in the Pali canon? Or are the rituals we see today later additions perhaps emerging from specific cultural or historic contexts.
I do not know of a sutta where the Buddha suggested ritual. (There may be one; I just don't know of it.) But I do know of a sutta where the Buddha guided a follower to understand that ritual is ineffective. In SN 42.6, Paccha-bhumika Sutta: [Brahmans] of the Western Land the Buddha gave 4 examples of crowds trying to affect an outcome with rituals. Here are two for example:

&quot;Very well, then, headman, I will question you on this matter. Answer as you see fit. What do you think: There is the case where a man is one who takes life, steals, indulges in illicit sex; is a liar, one who speaks divisive speech, harsh speech, &amp; idle chatter; is greedy, bears thoughts of ill-will, &amp; holds to wrong views. Then a great crowd of people, gathering &amp; congregating, would pray, praise, &amp; circumambulate with their hands palm-to-palm over the heart [saying,] 'May this man, at the break-up of the body, after death, reappear in a good destination, the heavenly world!' What do you think: would that man — because of the prayers, praise, &amp; circumambulation of that great crowd of people — at the break-up of the body, after death, reappear in a good destination, the heavenly world?&quot;
&quot;No, lord.&quot;

and also:

&quot;Suppose a man were to throw a jar of ghee or a jar of oil into a deep lake of water, where it would break. There the shards &amp; jar-fragments would go down, while the ghee or oil would come up. Then a great crowd of people, gathering &amp; congregating, would pray, praise, &amp; circumambulate with their hands palm-to-palm over the heart [saying,] 'Sink, O ghee/oil! Submerge, O ghee/oil! Go down, O ghee/oil!' What do you think: would that ghee/oil, because of the prayers, praise, &amp; circumambulation of that great crowd of people sink, submerge, or go down?&quot;
&quot;No, lord.&quot;

The sutta ends with the only effective &quot;ritual&quot; that I'm aware of from this time; which is the listener going for refuge.

&quot;I go to the Blessed One for refuge, to the Dhamma, &amp; to the community of monks. May the Blessed One remember me as a lay follower who has gone for refuge from this day forward, for life.&quot;