I like it!
You probably should consider describing the phonology of the tone system in more detail though. There's scope to do all sorts of interesting phonological things with tones!
This is my first time doing a conlang with tones, so i don't know much about them.
Also, from what I've learnt about tones in phonology, there's a rule that the underlying representation of the word can't have two of the same tone adjacent, although tones can be attached to multiple syllables in a row. (So, for example, something like [táká] would have one high tone attached to both syllables.) [That's called the Obligatory Contour Principle if you want to look it up.] This means interesting things can happen when you add an affix of the same tone as its base (for example, in Shona, a stem with a high tone changes it to a low tone if you add a prefix with a high tone).
Tones apparently also have a habit of moving around: in Somali, for example, you can't have a high tone at the end of a phrase, so it gets moved to the penultimate syllable if a syllable with a high tone ends up in phrase final position.
One thing to think about as well is that the phonological theory of tones I'm familiar with analyses them as on a separate 'tier' of the representation of the word, so that the string of tones is separate from the other segments of the word underlyingly, and is then linked to appropriate tone bearing units in the surface form.
Edit: A bit of further reading suggests that the Obligatory Contour Principle isn't necessarily universal (Shona, for example, doesn't seem to have a problem with multiple adjacent low tones, given changes a high tone to a low one doesn't seem to have any effect on a following low tone [although it could just merge with the later low tone, given this is another way languages can deal with two adjacent tones of the same time]).