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Smart parameter recommendations when primer design fails.

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Overview

When Primer3 fails to find suitable primers, PrimerLab analyzes the failure and suggests parameter adjustments.

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How It Works

  1. Analyze Failure — Parse Primer3 error messages
  2. Identify Cause — Determine which constraint failed
  3. Suggest Fix — Recommend specific parameter changes

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Example Output

❌ Design failed: No primers found

💡 Suggestions:
  • Tm constraint too tight - try relaxing to 55-65°C
  • Consider increasing product_size_range to 150-800 bp
  • GC content may be limiting - try 35-65%

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Common Suggestions

Failure ReasonSuggested Action
Tm out of rangeWiden Tm constraints
GC content issuesWiden GC range
No products in sizeIncrease product size range
Probe Tm issuesAdjust probe Tm range

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Automatic in CLI

Suggestions appear automatically when design fails: 
$ primerlab run pcr --config strict.yaml

🔬 PrimerLab v0.1.6
...
❌ Design failed

💡 Auto-suggestions:
  1. Relax Tm range: 55.0 - 65.0 (current: 59.0 - 61.0)
  2. Increase product size: 100 - 800 bp

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Applying Suggestions

Edit your config based on suggestions: 
# Before (too strict)
tm: {min: 59.0, opt: 60.0, max: 61.0}

# After (relaxed)
tm: {min: 55.0, opt: 60.0, max: 65.0}