Can a creature with a Mind Blank spell active on itself target itself with Encode Thoughts?

Question

Can a creature with an active mind blank spell target itself with encode thoughts?

My gut instinct was no. Upon further review, maybe?

For context:

I am playing a divination wizard in a West Marches campaign and, if all goes well (i.e. I don't die during our capstone level-up quest), I will reach level 15, gaining access to 8th-level spells.

The character I play is quite concerned with information security and, as a result, will certainly be taking mind blank upon reaching 15th level. One of his concerns is that, if he maintains 24-hour-a-day uptime on blanking his mind, then he won't be able to encode any of his thoughts via encode thoughts.

Will he still be able to?

The mind blank spell description (PHB, p. 259-260) has a duration of 24 hours, and says:

Until the spell ends, one willing creature you touch is immune to psychic damage, any effect that would sense its emotions or read its thoughts, divination spells, and the charmed condition. The spell even foils wish spells and spells or effects of similar power used to affect the target's mind or to gain information about the target.

I think RAW, despite the hefty and powerful defenses offered by the spell, he should be able to. Here's my reasoning:

1. Mind blank prevents "any effect that would [...] read its thoughts". Encode thoughts isn't sensing any of his thoughts per se (right?), the wizard has his own thoughts naturally and the spell only copies them.
2. Encode thoughts (GGtR, p. 47) is an enchantment spell, not a divination.
3. Mind blank says, "The spell foils wish spells [...] used to affect the target's mind or gain information about the target." Encode thoughts neither affects the wizard's mind, nor gains information; the information about the target is already "gained" or known to the wizard innately, and his mind isn't affected, as the thought being encoded by the spell remains unaffected and in place and is only copied.

Is my thinking complete and correct? If this works, is it also RAI?

Related: Does the Encode Thoughts spell remove the target thought from memory, or does it create a copy?

Answer 1

Mind blank probably blocks encode thoughts

Looking at mind blank, the only relevant part of the spell is, as you say:

Until the spell ends, one willing creature you touch is immune to [...] any effect that would [...] read its thoughts [...]

And the critical text in encode thoughts is:

[...] you pull a memory, an idea, or a message from your mind and transform it into a tangible string of glowing energy called a thought strand [...]

Since the spell explicitly says you are pulling the thought from your mind, I think that pretty clearly qualifies it as an effect that reads your thoughts, which means mind blank would block the spell. You might argue that "a memory, an idea, or a message" is not the same as a thought, but given that the spell has "thought" in the name, I don't think there's a meaningful distinction to be made there.

Ask your DM if you can do it anyway

This is a cool idea, and your DM might be fine with just declaring that encode thoughts works through mind blank, using whatever plausible-sounding explanation you like (e.g. mind blank works like a one-way firewall that prevents intrusion while allowing "outbound connections") It's not like there are any huge balance implications to allowing it.

Alternative: Use another divination-blocking spell or item instead of mind blank

Consider that you might not actually need the mind blank spell. There are a number of lower-level alternatives to mind blank, such as nondetection and Mordenkainen’s private sanctum. These don't explicitly block thought-reading, but they do block divination magic. Hence, they will block most means of reading a person's thoughts, but they will definitely not block encode thoughts, which is an enchantment spell. There is also a Ring of Mind Shielding, which only blocks other creatures' attempts to read your thoughts, which means it won't interfere with your own spells. This might be ideal if you can obtain one.

Who is your wizard worried about having their thoughts read by? If they're worried about other spellcasters, nondetection and/or private sanctum should do the trick. If they're worried about creatures with natural mind-reading abilities that might not involve divination spells, then mind blank would be their only option.

Note that you're probably going to want access to one of these lower level spells anyway as a contingency, even if you decide that mind blank is what you need. Since mind blank is an 8th level spell, you'll be unable to cast it more than once per long rest for a while, which means that if you are ever denied a long rest for over 24 hours, your mind blank will wear off, and you'll need something else to cover the time until you can rest again.

Answer 2

RAW, no

According to the spell description, any effect that would sense your emotions or read your thoughts does not affect you. Since it doesn't include an exception that allows you to be affected if you are willing, we can reasonably conclude that you would be unable to encode your own thoughts.