rony-chat-bot/internal/persona/persona.go

// Package persona owns the bot's identity and the system prompt the LLM
// sees. The full prompt text lives in the YAML's `system_prompt` field
// (long, freeform, hand-tuned for the deployment). This package only
// adds the RAG context after it.
package persona

import (
	"github.com/VictorVargas/rony-llm-agent/pkg/persona"

	"github.com/VictorVargas/rony-chat-bot/internal/config"
)

// FromConfig returns a minimal persona used only for the UI greeting and
// the SSE event metadata. The system prompt itself comes from
// config.SystemPrompt, not from this struct — see BuildSystemPrompt.
func FromConfig(c *config.Config) (persona.Persona, error) {
	lang := c.Persona.Language
	if lang == "" {
		lang = "the user's language"
	}
	return persona.Persona{
		ID:       "rony",
		Name:     c.Persona.Name,
		Tone:     c.Persona.Tone,
		Language: lang,
	}, nil
}

// BuildSystemPrompt returns the full prompt for one chat turn:
//  1. The hand-written system prompt from the YAML (who Rony is, how to speak)
//  2. The project catalogue (omitted when empty)
//  3. The RAG block (omitted when the index returns no hits)
//
// The catalogue and RAG block are appended, not prepended, so the persona
// instructions always come first and the LLM never gets the chance to
// "forget" them.
//
// The catalogue goes before the excerpts on purpose: it is the closed set the
// model is allowed to name, and stating the boundary before showing the
// evidence measurably cuts invented project names on small models.
func BuildSystemPrompt(systemPrompt, catalog, ragContext string) string {
	out := systemPrompt
	if catalog != "" {
		out += "\n\n## Victor's complete project catalogue\n\n" + catalog +
			"\n\nThat is every project that exists. A name outside this list is not a real " +
			"project of Victor's and you must never use one."
	}
	if ragContext != "" {
		out += "\n\n## Relevant context from the portfolio\n\n" +
			"Use these excerpts to answer. Cite the project filename when you reference a detail. " +
			"If the excerpts don't contain the answer, say you don't have that information — do not invent.\n\n" +
			ragContext
	}
	return out
}