Strip leading double underscores to avoid breaking change

Author: Theodore Li

apps/sim/tools/exa/answer.ts

@@ -37,8 +37,8 @@ export const answerTool: ToolConfig<ExaAnswerParams, ExaAnswerResponse> = {
     pricing: {
       type: 'custom',
       getCost: (_params, output) => {
-        // Use _costDollars from Exa API response (internal field, stripped from final output)
-        const costDollars = output._costDollars as { total?: number } | undefined
+        // Use __costDollars from Exa API response (internal field, stripped from final output)
+        const costDollars = output.__costDollars as { total?: number } | undefined
         if (costDollars?.total) {
           return { cost: costDollars.total, metadata: { costDollars } }
         }
@@ -86,7 +86,7 @@ export const answerTool: ToolConfig<ExaAnswerParams, ExaAnswerResponse> = {
             url: citation.url,
             text: citation.text || '',
           })) || [],
-        _costDollars: data.costDollars,
+        __costDollars: data.costDollars,
       },
     }
   },

apps/sim/tools/exa/find_similar_links.ts

@@ -86,8 +86,8 @@ export const findSimilarLinksTool: ToolConfig<
     pricing: {
       type: 'custom',
       getCost: (_params, output) => {
-        // Use _costDollars from Exa API response (internal field, stripped from final output)
-        const costDollars = output._costDollars as { total?: number } | undefined
+        // Use __costDollars from Exa API response (internal field, stripped from final output)
+        const costDollars = output.__costDollars as { total?: number } | undefined
         if (costDollars?.total) {
           return { cost: costDollars.total, metadata: { costDollars } }
         }
@@ -167,7 +167,7 @@ export const findSimilarLinksTool: ToolConfig<
           highlights: result.highlights,
           score: result.score || 0,
         })),
-        _costDollars: data.costDollars,
+        __costDollars: data.costDollars,
       },
     }
   },

apps/sim/tools/exa/get_contents.ts

@@ -71,8 +71,8 @@ export const getContentsTool: ToolConfig<ExaGetContentsParams, ExaGetContentsRes
     pricing: {
       type: 'custom',
       getCost: (_params, output) => {
-        // Use _costDollars from Exa API response (internal field, stripped from final output)
-        const costDollars = output._costDollars as { total?: number } | undefined
+        // Use __costDollars from Exa API response (internal field, stripped from final output)
+        const costDollars = output.__costDollars as { total?: number } | undefined
         if (costDollars?.total) {
           return { cost: costDollars.total, metadata: { costDollars } }
         }
@@ -158,7 +158,7 @@ export const getContentsTool: ToolConfig<ExaGetContentsParams, ExaGetContentsRes
           summary: result.summary || '',
           highlights: result.highlights,
         })),
-        _costDollars: data.costDollars,
+        __costDollars: data.costDollars,
       },
     }
   },

apps/sim/tools/exa/search.ts

@@ -96,8 +96,8 @@ export const searchTool: ToolConfig<ExaSearchParams, ExaSearchResponse> = {
     pricing: {
       type: 'custom',
       getCost: (params, output) => {
-        // Use _costDollars from Exa API response (internal field, stripped from final output)
-        const costDollars = output._costDollars as { total?: number } | undefined
+        // Use __costDollars from Exa API response (internal field, stripped from final output)
+        const costDollars = output.__costDollars as { total?: number } | undefined
         if (costDollars?.total) {
           return { cost: costDollars.total, metadata: { costDollars } }
         }
@@ -199,7 +199,7 @@ export const searchTool: ToolConfig<ExaSearchParams, ExaSearchResponse> = {
           highlights: result.highlights,
           score: result.score,
         })),
-        _costDollars: data.costDollars,
+        __costDollars: data.costDollars,
       },
     }
   },

apps/sim/tools/index.ts

@@ -326,13 +326,15 @@ async function reportCustomDimensionUsage(
 }
 
 /**
- * Strips internal fields (keys starting with underscore) from output.
- * Used to hide internal data (e.g., _costDollars) from end users.
+ * Strips internal fields (keys starting with `__`) from tool output before
+ * returning to users. The double-underscore prefix is reserved for transient
+ * data (e.g. `__costDollars`) and will never collide with legitimate API
+ * fields like `_id`.
  */
 function stripInternalFields(output: Record<string, unknown>): Record<string, unknown> {
   const result: Record<string, unknown> = {}
   for (const [key, value] of Object.entries(output)) {
-    if (!key.startsWith('_')) {
+    if (!key.startsWith('__')) {
       result[key] = value
     }
   }
@@ -368,6 +370,7 @@ async function applyHostedKeyCostToResult(
       },
     }
   }
+
 }
 
 /**
@@ -785,7 +788,6 @@ export async function executeTool(
         )
       }
 
-      // Strip internal fields (keys starting with _) from output before returning
       const strippedOutput = stripInternalFields(finalResult.output || {})
 
       return {
@@ -841,7 +843,6 @@ export async function executeTool(
       )
     }
 
-    // Strip internal fields (keys starting with _) from output before returning
     const strippedOutput = stripInternalFields(finalResult.output || {})
 
     return {