Warn about broad tool response projections

crates/crank-core/tests/unit/tool_quality.rs

@@ -1,6 +1,7 @@
 use crank_core::{
-    ToolDescription, ToolQualityFinding, ToolQualityReport, ToolQualitySchemaNode,
-    ToolQualitySeverity, analyze_tool_identity_quality, analyze_tool_schema_quality,
+    ToolDescription, ToolQualityFinding, ToolQualityMappingRule, ToolQualityMappingSet,
+    ToolQualityReport, ToolQualitySchemaNode, ToolQualitySeverity, analyze_tool_identity_quality,
+    analyze_tool_response_projection_quality, analyze_tool_schema_quality,
 };
 
 #[test]
@@ -181,6 +182,59 @@ fn recommends_enum_for_mode_like_string_parameter() {
     ));
 }
 
+#[test]
+fn warns_when_output_mapping_returns_full_response_body() {
+    let mapping = ToolQualityMappingSet {
+        rules: vec![ToolQualityMappingRule {
+            source: "$.response.body".to_owned(),
+            target: "$.output".to_owned(),
+        }],
+    };
+
+    let report = analyze_tool_response_projection_quality(&mapping);
+
+    assert!(has_finding(
+        &report,
+        "response_projection_full_body",
+        ToolQualitySeverity::Warning
+    ));
+}
+
+#[test]
+fn accepts_output_mapping_with_selected_fields() {
+    let mapping = ToolQualityMappingSet {
+        rules: vec![ToolQualityMappingRule {
+            source: "$.response.body.rates.EUR".to_owned(),
+            target: "$.output.rate".to_owned(),
+        }],
+    };
+
+    let report = analyze_tool_response_projection_quality(&mapping);
+
+    assert!(!report.blocking);
+    assert!(report.findings.is_empty());
+}
+
+#[test]
+fn marks_large_output_projection_as_info() {
+    let mapping = ToolQualityMappingSet {
+        rules: (0..12)
+            .map(|index| ToolQualityMappingRule {
+                source: format!("$.response.body.field_{index}"),
+                target: format!("$.output.field_{index}"),
+            })
+            .collect(),
+    };
+
+    let report = analyze_tool_response_projection_quality(&mapping);
+
+    assert!(has_finding(
+        &report,
+        "response_projection_many_fields",
+        ToolQualitySeverity::Info
+    ));
+}
+
 fn has_finding(report: &ToolQualityReport, code: &str, severity: ToolQualitySeverity) -> bool {
     report
         .findings