Llm_tagger: Failed to parse JSON response for post 30871: unexpected character (after tags) at line... [parse.c:706] in '{"tags":":["

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AI-generated summary

A user, kuaza, is experiencing issues with the automatic tagging feature in Discourse, encountering JSON parsing errors. The errors include unexpected characters in the JSON response and a NoMethodError when processing posts. sam asks which LLM is being used, suggesting that the LLM might be generating malformed JSON. kuaza mentions that GPT-5 Mini and 4.1 IDE did not work properly. awesomerobot inquires about the JSON response format in the persona settings, providing an example format. kuaza adjusts the settings and tries again with Bird GPT-4. awesomerobot corrects the JSON format, suggesting that the tags should be an array of strings. kuaza continues to encounter errors but eventually resolves the issue by ensuring the tags are an array of strings and confidence is an integer. Lhc_fl suggests using tools like json-repair to fix JSON syntax errors in LLM responses.

1

What could be the cause of this error? I have configured automatic tagging, but it is not functioning. I am encountering this error on the error page.

llm_tagger: Failed to parse JSON response for post 30871: unexpected character (after tags) at line 45020, column 3 [parse.c:706] in '{"tags":":["

And

llm_tagger: failed to process post 30930 /t/xxxxxx-1758567315538/1502/1 : NoMethodError : private method `select' called for an instance of String

Full Message and Backtrace

Message

llm_tagger: Failed to parse JSON response for post 30871: unexpected character (after tags) at line 45020, column 3 [parse.c:706] in '{"tags":":["

...

Backtrace

/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activesupport-8.0.2.1/lib/active_support/broadcast_logger.rb:130:in `block in warn'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activesupport-8.0.2.1/lib/active_support/broadcast_logger.rb:231:in `block in dispatch'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activesupport-8.0.2.1/lib/active_support/broadcast_logger.rb:231:in `each'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activesupport-8.0.2.1/lib/active_support/broadcast_logger.rb:231:in `dispatch'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activesupport-8.0.2.1/lib/active_support/broadcast_logger.rb:130:in `warn'
/var/www/discourse/plugins/discourse-ai/lib/automation/llm_tagger.rb:162:in `rescue in handle'
/var/www/discourse/plugins/discourse-ai/lib/automation/llm_tagger.rb:90:in `handle'
/var/www/discourse/plugins/discourse-ai/discourse_automation/llm_tagger.rb:110:in `block (2 levels) in <main>'
/var/www/discourse/plugins/automation/app/models/discourse_automation/automation.rb:158:in `block in trigger!'
/var/www/discourse/plugins/automation/app/models/discourse_automation/stat.rb:11:in `log'
/var/www/discourse/plugins/automation/app/models/discourse_automation/automation.rb:156:in `trigger!'
/var/www/discourse/plugins/automation/app/jobs/regular/discourse_automation/trigger.rb:29:in `execute'
/var/www/discourse/app/jobs/base.rb:318:in `block (2 levels) in perform'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/rails_multisite-7.0.0/lib/rails_multisite/connection_management/null_instance.rb:49:in `with_connection'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/rails_multisite-7.0.0/lib/rails_multisite/connection_management.rb:17:in `with_connection'
/var/www/discourse/app/jobs/base.rb:305:in `block in perform'
/var/www/discourse/app/jobs/base.rb:301:in `each'
/var/www/discourse/app/jobs/base.rb:301:in `perform'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/sidekiq-7.3.9/lib/sidekiq/processor.rb:220:in `execute_job'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/sidekiq-7.3.9/lib/sidekiq/processor.rb:185:in `block (4 levels) in process'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/sidekiq-7.3.9/lib/sidekiq/middleware/chain.rb:180:in `traverse'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/sidekiq-7.3.9/lib/sidekiq/middleware/chain.rb:183:in `block in traverse'
/var/www/discourse/lib/sidekiq/discourse_event.rb:6:in `call'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/sidekiq-7.3.9/lib/sidekiq/middleware/chain.rb:182:in `traverse'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/sidekiq-7.3.9/lib/sidekiq/middleware/chain.rb:183:in `block in traverse'
/var/www/discourse/lib/sidekiq/pausable.rb:131:in `call'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/sidekiq-7.3.9/lib/sidekiq/middleware/chain.rb:182:in `traverse'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/sidekiq-7.3.9/lib/sidekiq/middleware/chain.rb:183:in `block in traverse'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/sidekiq-7.3.9/lib/sidekiq/job/interrupt_handler.rb:9:in `call'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/sidekiq-7.3.9/lib/sidekiq/middleware/chain.rb:182:in `traverse'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/sidekiq-7.3.9/lib/sidekiq/middleware/chain.rb:183:in `block in traverse'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/sidekiq-7.3.9/lib/sidekiq/metrics/tracking.rb:26:in `track'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/sidekiq-7.3.9/lib/sidekiq/metrics/tracking.rb:134:in `call'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/sidekiq-7.3.9/lib/sidekiq/middleware/chain.rb:182:in `traverse'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/sidekiq-7.3.9/lib/sidekiq/middleware/chain.rb:173:in `invoke'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/sidekiq-7.3.9/lib/sidekiq/processor.rb:184:in `block (3 levels) in process'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/sidekiq-7.3.9/lib/sidekiq/processor.rb:145:in `block (6 levels) in dispatch'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/sidekiq-7.3.9/lib/sidekiq/job_retry.rb:118:in `local'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/sidekiq-7.3.9/lib/sidekiq/processor.rb:144:in `block (5 levels) in dispatch'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/sidekiq-7.3.9/lib/sidekiq/config.rb:39:in `block in <class:Config>'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/sidekiq-7.3.9/lib/sidekiq/processor.rb:139:in `block (4 levels) in dispatch'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/sidekiq-7.3.9/lib/sidekiq/processor.rb:281:in `stats'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/sidekiq-7.3.9/lib/sidekiq/processor.rb:134:in `block (3 levels) in dispatch'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/sidekiq-7.3.9/lib/sidekiq/job_logger.rb:15:in `call'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/sidekiq-7.3.9/lib/sidekiq/processor.rb:133:in `block (2 levels) in dispatch'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/sidekiq-7.3.9/lib/sidekiq/job_retry.rb:85:in `global'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/sidekiq-7.3.9/lib/sidekiq/processor.rb:132:in `block in dispatch'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/sidekiq-7.3.9/lib/sidekiq/job_logger.rb:40:in `prepare'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/sidekiq-7.3.9/lib/sidekiq/processor.rb:131:in `dispatch'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/sidekiq-7.3.9/lib/sidekiq/processor.rb:183:in `block (2 levels) in process'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/sidekiq-7.3.9/lib/sidekiq/processor.rb:182:in `handle_interrupt'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/sidekiq-7.3.9/lib/sidekiq/processor.rb:182:in `block in process'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/sidekiq-7.3.9/lib/sidekiq/processor.rb:181:in `handle_interrupt'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/sidekiq-7.3.9/lib/sidekiq/processor.rb:181:in `process'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/sidekiq-7.3.9/lib/sidekiq/processor.rb:86:in `process_one'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/sidekiq-7.3.9/lib/sidekiq/processor.rb:76:in `run'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/sidekiq-7.3.9/lib/sidekiq/component.rb:10:in `watchdog'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/sidekiq-7.3.9/lib/sidekiq/component.rb:19:in `block in safe_thread'
1 Like
2

which llm are you using?

Looks like it is generating malformed JSON and we need to do some extra work to correct for it.

1 Like
3

I did not provide GPT-5 Mini or 4.1 IDE, as they did not function properly and displayed the same error.

and this error

llm_tagger: failed to process post 30930 /t/xxxxxx-1758567315538/1502/1 : NoMethodError : private method `select' called for an instance of String
1 Like
5

How is your JSON response formatted in the persona settings? is it:

{
"tags": "[string]",
"confidence": "integer"
}

I’ve used this successfully with GPT4o and Claude… but will try some others

1 Like
6

I have made the recommended adjustments. I shall attempt it with Bird GPT-4.

image
image440×827 34.3 KB

1 Like
7

That’s close but not quite right, you need to select array first and then set the array_type as a string so it says "tags": ["string"]

image
image696×596 7.55 KB

3 Likes
8

I had been wondering why it didn’t turn out as in the example, but I didn’t mind. Now, I will try it this way as well. (I feel quite foolish :D)

llm_tagger: Failed to parse JSON response for post 30972: unexpected character (after confidence) at line 2703, column 19 [parse.c:706] in '{"tags": ["psikoloji", "eğitim", "aile"], "confidence":

llm_tagger: failed to process post 30990 /t/gecici-baslik-1758843990882/17521/1 : NoMethodError : undefined method <’ for an instance of Array`

9

The labels are an array of strings, and setting ‘confidence’ solely as an integer resolved the issue. I apologize for the false alarm. <3

{
"tags": "[string]",
"confidence": "integer"
}
2 Likes
10

https://github.com/RealAlexandreAI/json-repair

I’m a little curious if, we can use similar tools to try to fix it if a JSON syntax error is identified in the LLM response

2 Likes
11

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