In the spectrum of bioactive chemistry, probes and drugs can be regarded as broad band but others are also relevant to ADEV because their criteria overlap (even if not practically amenable to strict definitions). Of these 'Tool compound' is perhaps the loosest classification being used for any chemistry with even a low level of perturbation specificity but still deemed useful for investigating biological systems. For example, spider-venom toxin peptides can be used to probe (used in this context as verb rather than a noun) neuronal ion channels and receptors (see 'ArachnoServer 3.0: an online resource for automated discovery, analysis and annotation of spider toxins', 2018, PMID 29069336).