Is ritual described in the Pali canon?
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;