Does the description explain when to use this tool, when not to, or what alternatives exist?
The description provides explicit usage scenarios: 'when context is stale, the task is done, or you want to clear sensitive data'. It also suggests pairing with 'remember' and 'recall', offering guidance on complementary tools. However, it does not explicitly exclude situations where this tool should not be used or suggest direct alternatives beyond the paired tools, which would make it a 5.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.