I am probably missing something obvious but for the death of me I can't figure out what.

Homebrewing an otter to serve both as a companion and a wild shape as needed: https://www.dndbeyond.com/monsters/3164133-otter

The Bite attack rolls just fine in Roll20 via Beyond20; it shows the attack roll and the damage roll. But the Claws roll only shows the damage without rolling the attack itself. I've copy-pasted the code from the Bite attack, replacing 'Bite' with 'Claws' as appropriate:

Bite. Melee Weapon Attack:

[rollable]+4;{"diceNotation":"1d20+4","rollType":"to hit","rollAction":"Bite"}[/rollable] to hit, reach 5 ft., one target. Hit: 4 [rollable](1d6 - 1);{"diceNotation":"1d6-1","rollType":"damage","rollAction":"Bite","rollDamageType":"piercing"}[/rollable] piercing damage.

 Claws. Melee Weapon Attack (Finesse):

[rollable]+4;{"diceNotation":"1d20+4","rollType":"to hit","rollAction":"Claws"}[/rollable] to hit, reach 5 ft., one target. Hit: 4 [rollable](1d4 + 2);{"diceNotation":"1d4+2","rollType":"damage","rollAction":"Claws","rollDamageType":"slashing"}[/rollable] slashing damage.

 What am I doing wrong?

Oh, and while we're at it, for some reason the Bite attack insists on claiming it's adding 1 instead of subtracting it, but the end result is what it should be. Still tinkering with that but not as worried as long as the result is as expected.

It might be one of two things:

1. You might have inadvertently used the text version of quotation marks instead of the html version. I can’t tell when it’s presented as pre text instead of paragraph text. The html code for a text quotation is either “ or ” and looks like either “ or ”depending on which side of the word it’s on. But an html quotation looks like this: ". See the difference? You have to use the html quotations or it won’t work on DDB. You can check that looking at the html view of the Actions field by hitting this button above the field:

2. It could be the Beyond20 extension interfering with things, which is probably what’s making the -1 read as a +1. Try turning that extension off and see if that doesn’t solve the problem for you.

Went through the code block for the Claws and manually replaced all the quotation with a fresh one, no change. Disabling Beyond20 removes the buttons I'm using to send the rolls to Roll20, so that's not a workable solution, unfortunately.

Beyond20 is not supported by DDB, and in fact they recommend against using it because it often causes problems such as this. It’s a “use at your own risk” extension.

Alright; is there a different addon that sends rolls etc. to Roll20 I could use instead?

Not that I know of, but maybe. I don’t use a VTT like Roll20, so I don’t really know.

Problem solved! Apparently Beyond20 or DND Beyond itself is extremely finicky in this way; having (Finesse) in there is what broke it, but putting Finesse Melee Weapon Attack instead makes it work fine. Since the only use of it is to point out the claws use Dex as their mod this seems acceptable to me.

Ahh. Since the bite uses Str instead of Dex and has a -1 to damage instead of a +2, the attack modifier should only be +1, not +4.