Fix error swallowing by propagating JSON serialization errors to LLM

server/src/handlers/meta.rs

@@ -70,9 +70,9 @@ impl McpTool for QueryDecisionsHandler {
                     }
                 })
                 .collect();
-            serde_json::to_string(&filtered).unwrap_or_default()
-        });
-        Ok(data.to_string())
+            serde_json::to_string(&filtered).map_err(|e| e.to_string())
+        })?;
+        Ok(data)
     }
 }
 
@@ -129,9 +129,9 @@ impl McpTool for SearchErrorFixesHandler {
                         || contains_ignore_ascii_case(&f.solution, &q)
                 })
                 .collect();
-            serde_json::to_string(&filtered).unwrap_or_default()
-        });
-        Ok(data.to_string())
+            serde_json::to_string(&filtered).map_err(|e| e.to_string())
+        })?;
+        Ok(data)
     }
 }
 
@@ -180,8 +180,8 @@ impl McpTool for QueryRecentChangesHandler {
     async fn execute(&self, _args: Value, state: Arc<MemoryState>) -> Result<String, String> {
         let data = state
             .ledger
-            .read_with(|l| serde_json::to_string(l).unwrap_or_else(|_| "[]".to_string()));
-        Ok(data.to_string())
+            .read_with(|l| serde_json::to_string(l).map_err(|e| e.to_string()))?;
+        Ok(data)
     }
 }
 
@@ -229,7 +229,7 @@ impl McpTool for ReadPreferencesHandler {
         let data = state
             .prefs
             .read_with(|prefs| serde_json::to_string(prefs).unwrap_or_default());
-        Ok(data.to_string())
+        Ok(data)
     }
 }
 
@@ -319,9 +319,9 @@ impl McpTool for ListTechDebtHandler {
                     d.namespace == req.namespace && (req.include_resolved || !d.is_resolved)
                 })
                 .collect();
-            serde_json::to_string(&filtered).unwrap_or_default()
-        });
-        Ok(data.to_string())
+            serde_json::to_string(&filtered).map_err(|e| e.to_string())
+        })?;
+        Ok(data)
     }
 }
 
@@ -370,8 +370,8 @@ impl McpTool for OmniSearchHandler {
                     }
                 }
             }
-            serde_json::to_value(&kg_entities).unwrap_or_default()
-        });
+            serde_json::to_value(&kg_entities).map_err(|e| e.to_string())
+        })?;
 
         let mut matched_tasks = std::collections::HashSet::new();
         let mut matched_snippets = std::collections::HashSet::new();
@@ -407,8 +407,8 @@ impl McpTool for OmniSearchHandler {
                     }
                 })
                 .collect();
-            serde_json::to_value(&filtered).unwrap_or_default()
-        });
+            serde_json::to_value(&filtered).map_err(|e| e.to_string())
+        })?;
 
         let snippets_json = state.snippets.read_with(|all_snippets| {
             let filtered: Vec<_> = all_snippets
@@ -425,8 +425,8 @@ impl McpTool for OmniSearchHandler {
                     }
                 })
                 .collect();
-            serde_json::to_value(&filtered).unwrap_or_default()
-        });
+            serde_json::to_value(&filtered).map_err(|e| e.to_string())
+        })?;
 
         let adrs_json = state.adrs.read_with(|all_adrs| {
             let filtered: Vec<_> = all_adrs
@@ -445,8 +445,8 @@ impl McpTool for OmniSearchHandler {
                     }
                 })
                 .collect();
-            serde_json::to_value(&filtered).unwrap_or_default()
-        });
+            serde_json::to_value(&filtered).map_err(|e| e.to_string())
+        })?;
 
         let q = req.query;
         let tech_debts_json = state.tech_debts.read_with(|debts| {
@@ -469,8 +469,8 @@ impl McpTool for OmniSearchHandler {
                     }
                 })
                 .collect();
-            serde_json::to_value(&filtered).unwrap_or_default()
-        });
+            serde_json::to_value(&filtered).map_err(|e| e.to_string())
+        })?;
 
         let memos_json = state.handoff_memos.read_with(|memos| {
             let filtered: Vec<_> = memos
@@ -490,8 +490,8 @@ impl McpTool for OmniSearchHandler {
                     }
                 })
                 .collect();
-            serde_json::to_value(&filtered).unwrap_or_default()
-        });
+            serde_json::to_value(&filtered).map_err(|e| e.to_string())
+        })?;
 
         let error_fixes_json = state.error_fixes.read_with(|fixes| {
             let filtered: Vec<_> = fixes
@@ -501,8 +501,8 @@ impl McpTool for OmniSearchHandler {
                         || contains_ignore_ascii_case(&f.solution, &q)
                 })
                 .collect();
-            serde_json::to_value(&filtered).unwrap_or_default()
-        });
+            serde_json::to_value(&filtered).map_err(|e| e.to_string())
+        })?;
 
         let report = serde_json::json!({
             "knowledge_graph": kg_json,