name: oa-prompting-model-tiering
description: "Model selection guide for oa agents: haiku/sonnet/opus by task type. Use when choosing --model for oa run or oa pipeline. Activates for: which model, claude/haiku, claude/sonnet, claude/opus, model selection, --model."
user-invocable: false
Critical Rules
- ALWAYS use the
claude/sonnet ID format for --model, never claude-sonnet-4-6 — because oa run uses short model aliases, not Anthropic API IDs.
- ALWAYS specify
--model explicitly — because the default may change across oa-cli versions, producing unpredictable behavior.
Model Tiering Table
| Task Type |
Model |
Rationale |
| Scanning, listing, parsing, formatting |
claude/haiku |
Fast, cheap; structured output only |
| Writing, coding, implementation |
claude/sonnet |
DEFAULT — balanced quality/speed |
| Architecture, deep reasoning, complex orchestration |
claude/opus |
Maximum depth; use sparingly |
| QA, validation, review |
claude/sonnet |
Needs judgment, not just speed |
| Research (broad) |
claude/sonnet |
Good breadth coverage |
| Research (deep analysis) |
claude/opus |
When depth > speed |
| Batch processing (repetitive) |
claude/haiku |
Cost efficiency at scale |
Decision Tree
Task type?
├── Scanning / listing / formatting / parsing → claude/haiku
├── Writing / coding / implementation / review → claude/sonnet (DEFAULT)
└── Architecture / deep reasoning / orchestration planning → claude/opus
Patterns
Pattern 1: Correct model flag format
oa run "Implement the auth module" --name builder --model claude/sonnet --direct
oa run "Plan the architecture" --name planner --model claude/opus --direct
oa run "Convert CSV to JSON" --name converter --model claude/haiku --direct
Pattern 2: Model by role in a pipeline
oa run "Plan all implementation steps" --name planner --model claude/opus --direct
oa run "Implement step 1" --name builder-a --model claude/sonnet --direct
oa run "Convert file to JSON" --name converter --model claude/haiku --direct
Anti-Patterns
- Bad:
--model claude — bare alias, version-unstable
- Good:
--model claude/sonnet — explicit tier
- Bad:
--model anthropic/claude-sonnet-4-6 — Anthropic API ID, not oa-cli alias
- Good:
--model claude/sonnet
- Bad: Using
claude/opus for all tasks — expensive and slow for simple work
- Good: Reserve opus for architecture and deep reasoning only
References
- Related: oa-orchestration-spawn, oa-prompting-5element, oa-orchestration-patterns
By