When the model calls a tool with invalid JSON input multiple times in a row, Claude Code now injects a reminder into the next turn that includes the tool's full JSON Schema. This gives the model concrete structural guidance instead of just repeating a generic error.
Text injected: "This call has now failed validation N times in a row. The <tool> tool's input schema is: <schema>. Match the parameter names and types exactly on the next attempt."
Evidence
Validation failure counter (search for "This call has now failed validation") — Bfi() at line ~172918
Strings lifted out of the shipped bundle, so the claim above can be checked against them.