btw_tools errors: trailing garbage and premature EOF

[bianchenhao]

Recently, when I use btw app with claude 4.6 opus by my own gateway, it raised errors below several times:

**An error occurred:**
parse error: trailing garbage
          start": 380, "line_end": 440}{"_intent": "Read the do_fork_s
                     (right here) ------^

**An error occurred:**
parse error: premature EOF
                                       {"_intent": "Implement the fork
                     (right here) ------^

> sessionInfo()
R version 4.3.2 (2023-10-31)
Platform: x86_64-pc-linux-gnu (64-bit)
Running under: Ubuntu 22.04.3 LTS

Matrix products: default
BLAS:   /usr/lib/x86_64-linux-gnu/openblas-pthread/libblas.so.3 
LAPACK: /usr/lib/x86_64-linux-gnu/openblas-pthread/libopenblasp-r0.3.20.so;  LAPACK version 3.10.0

locale:
 [1] LC_CTYPE=en_US.UTF-8       LC_NUMERIC=C              
 [3] LC_TIME=en_US.UTF-8        LC_COLLATE=en_US.UTF-8    
 [5] LC_MONETARY=en_US.UTF-8    LC_MESSAGES=en_US.UTF-8   
 [7] LC_PAPER=en_US.UTF-8       LC_NAME=C                 
 [9] LC_ADDRESS=C               LC_TELEPHONE=C            
[11] LC_MEASUREMENT=en_US.UTF-8 LC_IDENTIFICATION=C       

time zone: Etc/UTC
tzcode source: system (glibc)

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base     

other attached packages:
 [1] biliauth_0.1.0       S7_0.2.0             coro_1.1.0          
 [4] dplyr_1.1.4          paws.storage_0.9.0   rlang_1.1.6         
 [7] jsonlite_2.0.0       base64enc_0.1-3      shinyjs_2.1.0       
[10] future_1.68.0        promises_1.3.3       pool_1.0.4          
[13] RMariaDB_1.3.1       DBI_1.2.3            shinychat_0.3.0.9000
[16] bslib_0.8.0          shiny_1.11.1         ellmer_0.4.0.9000   
[19] btw_1.1.0.9000       callr_3.7.3         

loaded via a namespace (and not attached):
 [1] rappdirs_0.3.3    sass_0.4.9        generics_0.1.4    paws.common_0.8.8
 [5] listenv_0.9.1     hms_1.1.3         digest_0.6.34     magrittr_2.0.3   
 [9] timechange_0.3.0  fastmap_1.2.0     processx_3.8.3    brio_1.1.4       
[13] ps_1.7.6          codetools_0.2-19  httr2_1.2.1       jquerylib_0.1.4  
[17] cli_3.6.5         crayon_1.5.2      parallelly_1.45.1 commonmark_2.0.0 
[21] bit64_4.0.5       withr_3.0.2       cachem_1.1.0      tools_4.3.2      
[25] parallel_4.3.2    memoise_2.0.1     httpuv_1.6.13     globals_0.18.0   
[29] curl_7.0.0        vctrs_0.6.5       R6_2.6.1          mime_0.13        
[33] lubridate_1.9.3   lifecycle_1.0.4   fs_1.6.6          bit_4.0.5        
[37] pkgconfig_2.0.3   pillar_1.11.0     later_1.4.2       glue_1.8.0       
[41] Rcpp_1.1.0        xfun_0.41         tidyselect_1.2.1  tibble_3.3.0     
[45] knitr_1.45        rstudioapi_0.17.1 xtable_1.8-4      htmltools_0.5.8.1
[49] compiler_4.3.2   

gateway:

client1 = ellmer::chat_claude(
    base_url = "http://llmapi.bilibili.co/v1",
    model = 'claude-4.6-opus',
    credentials = function() 'bsk-xxxx',
  )

[gadenbuie]

I've also encountered this and I don't think it's related to btw at all (I've seen this with Anthropic using just ellmer and non-btw tools). My best guess:

1. There could be an issue in ellmer wherein ellmer is not correctly preparing or parsing the JSON.
2. The model itself could have emitted invalid JSON (seems less likely to me).