# `Arcana.Loop.SystemPrompt`
[🔗](https://github.com/georgeguimaraes/arcana/blob/main/lib/arcana/loop/system_prompt.ex#L1)

Default system prompt for `Arcana.Loop`.

The prompt follows current best practices from Anthropic's tool use guidance,
OpenAI's GPT-5 prompting guide, and the Self-RAG / CRAG literature:

1. Structured into named markdown sections (works across providers).
2. Heavy detail in tool descriptions, not the system prompt.
3. Explicit when-NOT-to-call rules to avoid over-eager tool use.
4. Tool budget is mentioned even though `max_iterations` enforces it.
5. No `Thought:/Action:` prefixes since native tool calling drives the loop.
6. Self-critique on retrieval quality before answering.
7. Soft language, not aggressive `CRITICAL`/`MUST` (these cause over-trigger).

Override with the `:system_prompt` option on `Arcana.Loop.run/2`.

# `default`

```elixir
@spec default(keyword()) :: String.t()
```

Returns the default system prompt for the loop.

Takes the loop options so the prompt can mention the configured
`:max_iterations` budget.

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*Consult [api-reference.md](api-reference.md) for complete listing*