fix: normalize malformed Bash tool arguments from OpenAI-compatible providers

src/services/api/openaiShim.ts

@@ -42,6 +42,9 @@ import {
 } from './providerConfig.js'
 import { sanitizeSchemaForOpenAICompat } from '../../utils/schemaSanitizer.js'
 import { redactSecretValueForDisplay } from '../../utils/providerProfile.js'
+import {
+  normalizeToolArguments,
+} from './toolArgumentNormalization.js'
 
 type SecretValueSource = Partial<{
   OPENAI_API_KEY: string
@@ -476,6 +479,43 @@ function convertChunkUsage(
   }
 }
 
+function repairPossiblyTruncatedObjectJson(raw: string): string | null {
+  try {
+    const parsed = JSON.parse(raw)
+    return parsed && typeof parsed === 'object' && !Array.isArray(parsed) && typeof (parsed as Record<string, unknown>).command === 'string'
+      ? raw
+      : null
+  } catch {
+    const combinations = [
+      '}',
+      '"}',
+      ']}',
+      '"]}',
+      '}}',
+      '"}}',
+      ']}}',
+      '"]}}',
+      '"]}]}',
+      '}]}',
+    ]
+    for (const combo of combinations) {
+      try {
+        const repaired = raw + combo
+        const parsed = JSON.parse(repaired)
+        if (
+          parsed &&
+          typeof parsed === 'object' &&
+          !Array.isArray(parsed) &&
+          typeof (parsed as Record<string, unknown>).command === 'string'
+        ) {
+          return repaired
+        }
+      } catch {}
+    }
+    return null
+  }
+}
+
 /**
  * Async generator that transforms an OpenAI SSE stream into
  * Anthropic-format BetaRawMessageStreamEvent objects.
@@ -486,7 +526,16 @@ async function* openaiStreamToAnthropic(
 ): AsyncGenerator<AnthropicStreamEvent> {
   const messageId = makeMessageId()
   let contentBlockIndex = 0
-  const activeToolCalls = new Map<number, { id: string; name: string; index: number; jsonBuffer: string }>()
+  const activeToolCalls = new Map<
+    number,
+    {
+      id: string
+      name: string
+      index: number
+      jsonBuffer: string
+      normalizeAtStop: boolean
+    }
+  >()
   let hasEmittedContentStart = false
   let lastStopReason: 'tool_use' | 'max_tokens' | 'end_turn' | null = null
   let hasEmittedFinalUsage = false
@@ -577,11 +626,14 @@ async function* openaiStreamToAnthropic(
               }
 
               const toolBlockIndex = contentBlockIndex
+              const initialArguments = tc.function.arguments ?? ''
+              const normalizeAtStop = tc.function.name === 'Bash'
               activeToolCalls.set(tc.index, {
                 id: tc.id,
                 name: tc.function.name,
                 index: toolBlockIndex,
-                jsonBuffer: tc.function.arguments ?? '',
+                jsonBuffer: initialArguments,
+                normalizeAtStop,
               })
 
               yield {
@@ -598,7 +650,7 @@ async function* openaiStreamToAnthropic(
               contentBlockIndex++
 
               // Emit any initial arguments
-              if (tc.function.arguments) {
+              if (tc.function.arguments && !normalizeAtStop) {
                 yield {
                   type: 'content_block_delta',
                   index: toolBlockIndex,
@@ -615,6 +667,11 @@ async function* openaiStreamToAnthropic(
                 if (tc.function.arguments) {
                   active.jsonBuffer += tc.function.arguments
                 }
+
+                if (active.normalizeAtStop) {
+                  continue
+                }
+
                 yield {
                   type: 'content_block_delta',
                   index: active.index,
@@ -642,6 +699,33 @@ async function* openaiStreamToAnthropic(
           }
           // Close active tool calls
           for (const [, tc] of activeToolCalls) {
+            if (tc.normalizeAtStop) {
+              let partialJson = tc.jsonBuffer
+              if (choice.finish_reason === 'tool_calls') {
+                const repairedStructuredJson = repairPossiblyTruncatedObjectJson(
+                  tc.jsonBuffer,
+                )
+                if (repairedStructuredJson) {
+                  partialJson = repairedStructuredJson
+                } else if (!/^\s*\{\s*"/.test(tc.jsonBuffer)) {
+                  partialJson = JSON.stringify(
+                    normalizeToolArguments(tc.name, tc.jsonBuffer),
+                  )
+                }
+              }
+
+              yield {
+                type: 'content_block_delta',
+                index: tc.index,
+                delta: {
+                  type: 'input_json_delta',
+                  partial_json: partialJson,
+                },
+              }
+              yield { type: 'content_block_stop', index: tc.index }
+              continue
+            }
+
             let suffixToAdd = ''
             if (tc.jsonBuffer) {
               try {
@@ -1087,12 +1171,10 @@ class OpenAIShimMessages {
 
     if (choice?.message?.tool_calls) {
       for (const tc of choice.message.tool_calls) {
-        let input: unknown
-        try {
-          input = JSON.parse(tc.function.arguments)
-        } catch {
-          input = { raw: tc.function.arguments }
-        }
+        const input = normalizeToolArguments(
+          tc.function.name,
+          tc.function.arguments,
+        )
         content.push({
           type: 'tool_use',
           id: tc.id,