Instruction Density and Rule Dropping
Opus: Tracks and satisfies 15+ simultaneous constraints reliably. Prioritizes naturally when constraints tension.
Haiku: Reliable with 5-7 simultaneous constraints. At 10+, may drop rules — particularly those in the middle of a list, those phrased passively, or those that conflict with example patterns.
Mitigation: Limit rules to 7. Group and prioritize.
BAD: 12 flat rules in a single list
GOOD:
CRITICAL (must never violate):
1. [rule]
2. [rule]
REQUIRED (always apply):
3. [rule]
4. [rule]
5. [rule]
PREFERRED (apply when possible):
6. [rule]
7. [rule]Additional strategies:
- Cross-reference rules in process steps: "Apply rules 1-3 to each item"
- Embed the most important rules in the examples, not just the rule list
- For complex rule sets, split into multiple prompts (one pass per rule group) rather than asking Haiku to apply all at once
- Repeat the single most important rule at the END of the prompt
If a rule is never demonstrated in the examples, Haiku is less likely to follow it. Every critical rule should appear in at least one example.