docs: check surrounding cases when changing boundaries

AGENTS.md

@@ -54,7 +54,7 @@ Use ESM TypeScript, two-space indentation, and the committed Oxfmt configuration
 
 Treat a boundary as a contract between the producer's actual representation and the consumer's required meaning. When implementing or auditing a boundary, trace the value through parsing, normalization, authorization, serialization, and the CLI/MCP result. Establish affected callers from their code paths; similar tool names or workflows do not prove that they share a schema or failure mode.
 
-When fixing a review finding, correct the failed assumption and inspect adjacent input representations, failure paths, and callers at the same boundary. Add regressions for the failure class, including how evidence and diagnostics reach affected CLI/MCP results, rather than only the reported example.
+When changing boundary behavior, inspect adjacent input representations, failure paths, and affected callers, and correct the underlying assumption across those cases.
 
 Keep portable evidence and scenario validation distinct from host-native execution checks. Absolute filesystem paths, file URLs, and HTTP paths have different semantics; do not substitute one platform's syntax for the domain concept. Interpret provider metadata according to its documented or observed producer behavior. When a transformation loses information, preserve the reported value and an explicit unknown rather than guessing a canonical identity.