How can I solve this error "invalid type (list) for variable" in brms

I tried to fit a poisson model, , I used the new function resp_rate instead of the offset term.

and I got a error like this:
Error in model.frame.default(all_vars_terms, data, na.action = na.pass, :
invalid type (list) for variable 'resp_rate(area)

My code:
fit_culm_numbers<-brm(formula=cNo~canopy*year2+resp_rate(area)+(1|plot),

  •          family = poisson(),
    
  •          data=dd,
    
  •                      seed=1,
    
  •          prior=c(set_prior("",class="Intercept"),
    
  •                  set_prior("",class="sd")),
    
  •          chains=4,
    
  •          iter=50000,
    
  •          warmup=20000,
    
  •          thin=1,
    
  •          control = list(adapt_delta=0.97,max_treedepth = 15,stepsize=0.001))
    

I try to use as.data.farame or unlist , but it was not work. I got the same error.

below is my data:

thanks everyone

I have never used this, but from looking at the examples in Additional Response Information — addition-terms • brms , I get the feeling that the syntax might be

 cNo| resp_rate(area) ~ canopy*year2+(1|plot)

does that work?

thanks for your answer》

there was no error by this way, but the results of this model used cNo|resp_rate(area), is same to the model without respa_rate,
so,I think the resp_rate function still not working.