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Fetch assistant prompt configuration from Langfuse #177

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099b937
Fetch Langfuse prompt for assistant instructions
jjmata Oct 1, 2025
d8804ea
Handle nil values when compiling Langfuse instructions
jjmata Oct 1, 2025
17f5c02
Fixes and prompt support
jjmata Oct 1, 2025
805d405
Fix {{variable}} replacement
jjmata Oct 1, 2025
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13 changes: 10 additions & 3 deletions app/models/assistant.rb
View file
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Original file line number Diff line number Diff line change
@@ -1,18 +1,24 @@
class Assistant
include Provided, Configurable, Broadcastable

attr_reader :chat, :instructions
attr_reader :chat, :instructions, :instructions_prompt

class << self
def for_chat(chat)
config = config_for(chat)
new(chat, instructions: config[:instructions], functions: config[:functions])
new(
chat,
instructions: config[:instructions],
instructions_prompt: config[:instructions_prompt],
functions: config[:functions]
)
end
end

def initialize(chat, instructions: nil, functions: [])
def initialize(chat, instructions: nil, instructions_prompt: nil, functions: [])
@chat = chat
@instructions = instructions
@instructions_prompt = instructions_prompt
@functions = functions
end

Expand All @@ -26,6 +32,7 @@ def respond_to(message)
responder = Assistant::Responder.new(
message: message,
instructions: instructions,
instructions_prompt: instructions_prompt,
function_tool_caller: function_tool_caller,
llm: get_model_provider(message.ai_model)
)
Expand Down
68 changes: 67 additions & 1 deletion app/models/assistant/configurable.rb
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Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -6,8 +6,11 @@
preferred_currency = Money::Currency.new(chat.user.family.currency)
preferred_date_format = chat.user.family.date_format

instructions_config = default_instructions(preferred_currency, preferred_date_format)

{
instructions: default_instructions(preferred_currency, preferred_date_format),
instructions: instructions_config[:content],
instructions_prompt: instructions_config[:prompt],
functions: default_functions
}
end
Expand All @@ -23,6 +26,60 @@
end

def default_instructions(preferred_currency, preferred_date_format)
langfuse_instructions = langfuse_default_instructions(preferred_currency, preferred_date_format)

if langfuse_instructions.present?
{
content: langfuse_instructions[:content],
prompt: langfuse_instructions
}
else
{
content: fallback_default_instructions(preferred_currency, preferred_date_format),
prompt: nil
}
end
end

def langfuse_default_instructions(preferred_currency, preferred_date_format)
return unless langfuse_client

prompt = langfuse_client.get_prompt("default_instructions")

compiled_prompt = prompt.compile(
preferred_currency_symbol: preferred_currency.symbol,
preferred_currency_iso_code: preferred_currency.iso_code,
preferred_currency_default_precision: preferred_currency.default_precision,
preferred_currency_default_format: preferred_currency.default_format,
preferred_currency_separator: preferred_currency.separator,
preferred_currency_delimiter: preferred_currency.delimiter,
preferred_date_format: preferred_date_format,
current_date: Date.current
)

content = case compiled_prompt
when String
compiled_prompt
when Array
compiled_prompt.filter_map { |message| message[:content] }.join("\n\n")
else
nil
end

Check failure on line 67 in app/models/assistant/configurable.rb

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Layout/EndAlignment: `end` at 67, 18 is not aligned with `content = case` at 60, 8.

return if content.blank?

{
name: prompt.name,
version: prompt.version,
template: prompt.prompt,
content: content
}
rescue => e
Rails.logger.warn("Langfuse prompt retrieval failed: #{e.message}")
nil
end

def fallback_default_instructions(preferred_currency, preferred_date_format)
<<~PROMPT
## Your identity
Expand Down Expand Up @@ -78,5 +135,14 @@
the data you're presenting represents and what context it is in (i.e. date range, account, etc.)
PROMPT
end

def langfuse_client
return unless ENV["LANGFUSE_PUBLIC_KEY"].present? && ENV["LANGFUSE_SECRET_KEY"].present?

@langfuse_client ||= Langfuse.new
rescue => e
Rails.logger.warn("Langfuse client initialization failed: #{e.message}")
nil
end
Comment on lines +183 to +190
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🛠️ Refactor suggestion | 🟠 Major

Extract duplicated langfuse_client to a shared concern.

This method is nearly identical to Provider::OpenAI#langfuse_client (lines 140-144 in app/models/provider/openai.rb). To follow DRY principles and maintain consistency, consider extracting this to a shared concern (e.g., LangfuseClientConcern) that both classes can include.

Create a new concern at app/models/concerns/langfuse_client_concern.rb:

module LangfuseClientConcern
  extend ActiveSupport::Concern

  class_methods do
    def langfuse_client
      return unless ENV["LANGFUSE_PUBLIC_KEY"].present? && ENV["LANGFUSE_SECRET_KEY"].present?

      @langfuse_client ||= Langfuse.new
    rescue => e
      Rails.logger.warn("Langfuse client initialization failed: #{e.message}")
      nil
    end
  end
end

Then include it in both Assistant::Configurable and Provider::OpenAI:

 module Assistant::Configurable
   extend ActiveSupport::Concern
+  include LangfuseClientConcern

   class_methods do
     # ...
-
-      def langfuse_client
-        return unless ENV["LANGFUSE_PUBLIC_KEY"].present? && ENV["LANGFUSE_SECRET_KEY"].present?
-
-        @langfuse_client ||= Langfuse.new
-      rescue => e
-        Rails.logger.warn("Langfuse client initialization failed: #{e.message}")
-        nil
-      end
   end
 end

As per coding guidelines.

🤖 Prompt for AI Agents 
In app/models/assistant/configurable.rb around lines 154 to 161 and
app/models/provider/openai.rb around lines 140 to 144, the langfuse_client
method is duplicated; extract it into a new concern at
app/models/concerns/langfuse_client_concern.rb that defines the class-level
langfuse_client (using ActiveSupport::Concern with class_methods), move the
existing implementation there (keeping the same ENV checks, memoization and
rescue logging), then remove the method from both Assistant::Configurable and
Provider::OpenAI and include the new LangfuseClientConcern in each class so they
share the single implementation.

end
end
6 changes: 4 additions & 2 deletions app/models/assistant/responder.rb
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -1,9 +1,10 @@
class Assistant::Responder
def initialize(message:, instructions:, function_tool_caller:, llm:)
def initialize(message:, instructions:, function_tool_caller:, llm:, instructions_prompt: nil)
@message = message
@instructions = instructions
@function_tool_caller = function_tool_caller
@llm = llm
@instructions_prompt = instructions_prompt
end

def on(event_name, &block)
Expand Down Expand Up @@ -31,7 +32,7 @@ def respond(previous_response_id: nil)
end

private
attr_reader :message, :instructions, :function_tool_caller, :llm
attr_reader :message, :instructions, :function_tool_caller, :llm, :instructions_prompt

def handle_follow_up_response(response)
streamer = proc do |chunk|
Expand Down Expand Up @@ -64,6 +65,7 @@ def get_llm_response(streamer:, function_results: [], previous_response_id: nil)
message.content,
model: message.ai_model,
instructions: instructions,
instructions_prompt: instructions_prompt,
functions: function_tool_caller.function_definitions,
function_results: function_results,
streamer: streamer,
Expand Down
1 change: 1 addition & 0 deletions app/models/provider/llm_concept.rb
View file
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Original file line number Diff line number Diff line change
Expand Up @@ -22,6 +22,7 @@ def chat_response(
prompt,
model:,
instructions: nil,
instructions_prompt: nil,
functions: [],
function_results: [],
streamer: nil,
Expand Down
60 changes: 39 additions & 21 deletions app/models/provider/openai.rb
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Original file line number Diff line number Diff line change
Expand Up @@ -62,6 +62,7 @@
prompt,
model:,
instructions: nil,
instructions_prompt: nil,
functions: [],
function_results: [],
streamer: nil,
Expand Down Expand Up @@ -112,6 +113,7 @@
model: model,
input: input_payload,
output: response.messages.map(&:output_text).join("\n"),
prompt: instructions_prompt,
session_id: session_id,
user_identifier: user_identifier
)
Expand All @@ -123,6 +125,7 @@
model: model,
input: input_payload,
output: parsed.messages.map(&:output_text).join("\n"),
prompt: instructions_prompt,
usage: raw_response["usage"],
session_id: session_id,
user_identifier: user_identifier
Expand All @@ -141,26 +144,41 @@
@langfuse_client = Langfuse.new
end

def log_langfuse_generation(name:, model:, input:, output:, usage: nil, session_id: nil, user_identifier: nil)
return unless langfuse_client

trace = langfuse_client.trace(
name: "openai.#{name}",
input: input,
session_id: session_id,
user_id: user_identifier
)
trace.generation(
name: name,
model: model,
input: input,
output: output,
usage: usage,
session_id: session_id,
user_id: user_identifier
)
trace.update(output: output)
rescue => e
Rails.logger.warn("Langfuse logging failed: #{e.message}")
def log_langfuse_generation(name:, model:, input:, output:, usage: nil, session_id: nil, user_identifier: nil, prompt: nil)

Check failure on line 147 in app/models/provider/openai.rb

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Layout/IndentationConsistency: Inconsistent indentation detected.
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⚠️ Potential issue | 🟡 Minor

Fix indentation to align with Ruby style guidelines.

The method definition has inconsistent indentation.

Apply this diff:

-  def log_langfuse_generation(name:, model:, input:, output:, usage: nil, session_id: nil, user_identifier: nil, prompt: nil)
+def log_langfuse_generation(name:, model:, input:, output:, usage: nil, session_id: nil, user_identifier: nil, prompt: nil)

Based on static analysis hints.

📝 Committable suggestion

‼️ IMPORTANT
Carefully review the code before committing. Ensure that it accurately replaces the highlighted code, contains no missing lines, and has no issues with indentation. Thoroughly test & benchmark the code to ensure it meets the requirements.

Suggested change
def log_langfuse_generation(name:, model:, input:, output:, usage: nil, session_id: nil, user_identifier: nil, prompt: nil)
def log_langfuse_generation(name:, model:, input:, output:, usage: nil, session_id: nil, user_identifier: nil, prompt: nil)
🧰 Tools
🪛 GitHub Check: ci / lint

[failure] 147-147:
Layout/IndentationConsistency: Inconsistent indentation detected.

🤖 Prompt for AI Agents 
In app/models/provider/openai.rb around line 147, the method definition `def
log_langfuse_generation...` is indented inconsistently; reformat the line to
follow Ruby style (2-space indentation) so it aligns with the other method
definitions in the class/module scope — move the `def` left to the same
indentation level as neighboring methods and ensure the parameter list and
closing `end` remain aligned accordingly.

return unless langfuse_client

trace = langfuse_client.trace(
name: "openai.#{name}",
input: input,
session_id: session_id,
user_id: user_identifier
)
generation_options = {
name: name,
model: model,
input: input,
output: output,
usage: usage,
session_id: session_id,
user_id: user_identifier
}

if prompt.present?
generation_options[:version] = prompt[:version] if prompt[:version]
metadata = {
prompt: {
name: prompt[:name],
version: prompt[:version],
content: prompt[:content],
template: prompt[:template]
}.compact
}
generation_options[:metadata] = metadata
end

trace.generation(**generation_options)
trace.update(output: output)
rescue => e
Rails.logger.warn("Langfuse logging failed: #{e.message}")
end
end
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