Observe Opal

Routing rules

If the user asks to write or fix OPAL

1. Read playbooks/opal-authoring-playbook.md
2. Open the minimal Layer 3 reference needed
3. Return valid OPAL, not pseudocode
4. Explain assumptions if dataset schema is missing

If the user asks for syntax or semantics

Open one of:

• syntax → references/opal-syntax-reference.md
• types/casts/operators → references/opal-types-and-operators-reference.md
• functions → references/opal-functions-reference.md
• verbs → references/opal-verbs-reference.md

If the user asks for shaping or multi-step transforms

Open:

• playbooks/opal-authoring-playbook.md
• references/opal-stages-and-subqueries-reference.md
• references/opal-patterns-and-recipes.md

If the user asks practical "how do I..." questions

Open references/opal-helpful-hints-reference.md first.

Output expectations

• Prefer readable multi-line OPAL for non-trivial queries
• Cast extracted fields explicitly when types are uncertain
• Filter early when possible
• Use stages/subqueries when logic branches or when an intermediate table improves clarity
• Pick output columns near the end when shaping datasets
• Preserve source field naming unless there is a strong reason to rename