fix: extend tool argument normalization to all tools and harden edge cases

- Extend STRING_ARGUMENT_TOOL_FIELDS to normalize Read, Write, Edit,
  Glob, and Grep plain-string arguments (fixes "Invalid tool parameters"
  errors reported by VennDev)
- Normalize streaming Bash args regardless of finish_reason, not only
  when finish_reason is 'tool_calls'
- Broaden isLikelyStructuredObjectLiteral to catch malformed object-shaped
  strings like {command:"pwd"} and {'command':'pwd'} (fixes CR2 from
  Vasanthdev2004)
- Apply blank/object-literal guard to all tools, not just Bash
- Extract duplicated JSON repair suffix combinations into shared constant
- Add 32 isolated unit tests for toolArgumentNormalization

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/services/api/openaiShim.test.ts

@@ -1420,7 +1420,7 @@ test('does not normalize incomplete streamed Bash commands when finish_reason is
     .map(event => (event.delta as Record<string, unknown>).partial_json)
     .join('')
 
-  expect(streamedInput).toBe('rg --fi')
+  expect(streamedInput).toBe('{"command":"rg --fi"}')
 })
 
 test('does not repair truncated Bash objects that do not contain command', async () => {

src/services/api/openaiShim.ts

@@ -479,6 +479,10 @@ function convertChunkUsage(
   }
 }
 
+const JSON_REPAIR_SUFFIXES = [
+  '}', '"}', ']}', '"]}', '}}', '"}}', ']}}', '"]}}', '"]}]}', '}]}'
+]
+
 function repairPossiblyTruncatedObjectJson(raw: string): string | null {
   try {
     const parsed = JSON.parse(raw)
@@ -486,19 +490,7 @@ function repairPossiblyTruncatedObjectJson(raw: string): string | null {
       ? raw
       : null
   } catch {
-    const combinations = [
-      '}',
-      '"}',
-      ']}',
-      '"]}',
-      '}}',
-      '"}}',
-      ']}}',
-      '"]}}',
-      '"]}]}',
-      '}]}',
-    ]
-    for (const combo of combinations) {
+    for (const combo of JSON_REPAIR_SUFFIXES) {
       try {
         const repaired = raw + combo
         const parsed = JSON.parse(repaired)
@@ -700,11 +692,10 @@ 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,
               )
+              let partialJson: string
               if (repairedStructuredJson) {
                 partialJson = repairedStructuredJson
               } else {
@@ -712,7 +703,6 @@ async function* openaiStreamToAnthropic(
                   normalizeToolArguments(tc.name, tc.jsonBuffer),
                 )
               }
-              }
 
               yield {
                 type: 'content_block_delta',
@@ -732,10 +722,7 @@ async function* openaiStreamToAnthropic(
                 JSON.parse(tc.jsonBuffer)
               } catch {
                 const str = tc.jsonBuffer.trimEnd()
-                const combinations = [
-                  '}', '"}', ']}', '"]}', '}}', '"}}', ']}}', '"]}}', '"]}]}', '}]}'
-                ]
-                for (const combo of combinations) {
+                for (const combo of JSON_REPAIR_SUFFIXES) {
                   try {
                     JSON.parse(str + combo)
                     suffixToAdd = combo

src/services/api/toolArgumentNormalization.test.ts

@@ -0,0 +1,184 @@
+import { describe, expect, test } from 'bun:test'
+import { normalizeToolArguments } from './toolArgumentNormalization'
+
+describe('normalizeToolArguments', () => {
+  describe('Bash tool', () => {
+    test('wraps plain string into { command }', () => {
+      expect(normalizeToolArguments('Bash', 'pwd')).toEqual({ command: 'pwd' })
+    })
+
+    test('wraps multi-word command', () => {
+      expect(normalizeToolArguments('Bash', 'ls -la /tmp')).toEqual({
+        command: 'ls -la /tmp',
+      })
+    })
+
+    test('passes through structured JSON object', () => {
+      expect(
+        normalizeToolArguments('Bash', '{"command":"echo hi"}'),
+      ).toEqual({ command: 'echo hi' })
+    })
+
+    test('returns { raw } for blank string', () => {
+      expect(normalizeToolArguments('Bash', '')).toEqual({ raw: '' })
+      expect(normalizeToolArguments('Bash', '   ')).toEqual({ raw: '   ' })
+    })
+
+    test('returns { raw } for JSON-encoded blank string', () => {
+      expect(normalizeToolArguments('Bash', '""')).toEqual({ raw: '' })
+      expect(normalizeToolArguments('Bash', '"  "')).toEqual({ raw: '  ' })
+    })
+
+    test('returns { raw } for likely structured object literal that fails parse', () => {
+      expect(normalizeToolArguments('Bash', '{ "command": "pwd"')).toEqual({
+        raw: '{ "command": "pwd"',
+      })
+    })
+
+    test.each([
+      ['{command:"pwd"}'],
+      ["{'command':'pwd'}"],
+      ['{command: pwd}'],
+    ])(
+      'returns { raw } for malformed object-shaped string %s (does not wrap into command)',
+      (input) => {
+        expect(normalizeToolArguments('Bash', input)).toEqual({ raw: input })
+      },
+    )
+
+    test.each([
+      ['false', false],
+      ['null', null],
+      ['[]', [] as unknown[]],
+      ['0', 0],
+      ['true', true],
+      ['123', 123],
+    ])(
+      'preserves JSON literal %s as-is (does not wrap into command)',
+      (input, expected) => {
+        expect(normalizeToolArguments('Bash', input)).toEqual(expected)
+      },
+    )
+
+    test('wraps JSON-encoded string into { command }', () => {
+      expect(normalizeToolArguments('Bash', '"pwd"')).toEqual({
+        command: 'pwd',
+      })
+    })
+  })
+
+  describe('undefined arguments', () => {
+    test('returns empty object for undefined', () => {
+      expect(normalizeToolArguments('Bash', undefined)).toEqual({})
+      expect(normalizeToolArguments('UnknownTool', undefined)).toEqual({})
+    })
+  })
+
+  describe('Read tool', () => {
+    test('wraps plain string into { file_path }', () => {
+      expect(normalizeToolArguments('Read', '/home/user/file.txt')).toEqual({
+        file_path: '/home/user/file.txt',
+      })
+    })
+
+    test('wraps JSON-encoded string into { file_path }', () => {
+      expect(normalizeToolArguments('Read', '"/home/user/file.txt"')).toEqual({
+        file_path: '/home/user/file.txt',
+      })
+    })
+
+    test('passes through structured JSON object', () => {
+      expect(
+        normalizeToolArguments('Read', '{"file_path":"/tmp/f.txt","limit":10}'),
+      ).toEqual({ file_path: '/tmp/f.txt', limit: 10 })
+    })
+  })
+
+  describe('Write tool', () => {
+    test('wraps plain string into { file_path }', () => {
+      expect(normalizeToolArguments('Write', '/tmp/out.txt')).toEqual({
+        file_path: '/tmp/out.txt',
+      })
+    })
+
+    test('passes through structured JSON object', () => {
+      expect(
+        normalizeToolArguments(
+          'Write',
+          '{"file_path":"/tmp/out.txt","content":"hello"}',
+        ),
+      ).toEqual({ file_path: '/tmp/out.txt', content: 'hello' })
+    })
+  })
+
+  describe('Edit tool', () => {
+    test('wraps plain string into { file_path }', () => {
+      expect(normalizeToolArguments('Edit', '/tmp/edit.ts')).toEqual({
+        file_path: '/tmp/edit.ts',
+      })
+    })
+
+    test('passes through structured JSON object', () => {
+      expect(
+        normalizeToolArguments(
+          'Edit',
+          '{"file_path":"/tmp/f.ts","old_string":"a","new_string":"b"}',
+        ),
+      ).toEqual({ file_path: '/tmp/f.ts', old_string: 'a', new_string: 'b' })
+    })
+  })
+
+  describe('Glob tool', () => {
+    test('wraps plain string into { pattern }', () => {
+      expect(normalizeToolArguments('Glob', '**/*.ts')).toEqual({
+        pattern: '**/*.ts',
+      })
+    })
+
+    test('passes through structured JSON object', () => {
+      expect(
+        normalizeToolArguments('Glob', '{"pattern":"*.js","path":"/src"}'),
+      ).toEqual({ pattern: '*.js', path: '/src' })
+    })
+  })
+
+  describe('Grep tool', () => {
+    test('wraps plain string into { pattern }', () => {
+      expect(normalizeToolArguments('Grep', 'TODO')).toEqual({
+        pattern: 'TODO',
+      })
+    })
+
+    test('passes through structured JSON object', () => {
+      expect(
+        normalizeToolArguments('Grep', '{"pattern":"fixme","path":"/src"}'),
+      ).toEqual({ pattern: 'fixme', path: '/src' })
+    })
+  })
+
+  describe('unknown tools', () => {
+    test('returns { raw } for plain string', () => {
+      expect(normalizeToolArguments('UnknownTool', 'some value')).toEqual({
+        raw: 'some value',
+      })
+    })
+
+    test('passes through structured JSON object', () => {
+      expect(
+        normalizeToolArguments('UnknownTool', '{"key":"val"}'),
+      ).toEqual({ key: 'val' })
+    })
+
+    test('preserves JSON literals as-is', () => {
+      expect(normalizeToolArguments('UnknownTool', 'false')).toEqual(false)
+      expect(normalizeToolArguments('UnknownTool', 'null')).toEqual(null)
+      expect(normalizeToolArguments('UnknownTool', '[]')).toEqual([])
+    })
+
+    test('returns JSON-encoded string as parsed string for unknown tools', () => {
+      expect(normalizeToolArguments('UnknownTool', '"hello"')).toEqual(
+        'hello',
+      )
+    })
+  })
+})

src/services/api/toolArgumentNormalization.ts

@@ -1,5 +1,10 @@
 const STRING_ARGUMENT_TOOL_FIELDS: Record<string, string> = {
   Bash: 'command',
+  Read: 'file_path',
+  Write: 'file_path',
+  Edit: 'file_path',
+  Glob: 'pattern',
+  Grep: 'pattern',
 }
 
 function isBlankString(value: string): boolean {
@@ -7,7 +12,10 @@ function isBlankString(value: string): boolean {
 }
 
 function isLikelyStructuredObjectLiteral(value: string): boolean {
-  return /^\s*\{\s*"[^"\\]+"\s*:/.test(value)
+  // Match object-like patterns with key-value syntax:
+  // {"key":, {key:, {'key':, { "key" :, etc.
+  // But NOT bash compound commands like { pwd; } or { echo hi; }
+  return /^\s*\{\s*['"]?\w+['"]?\s*:/.test(value)
 }
 
 function isRecord(value: unknown): value is Record<string, unknown> {
@@ -52,11 +60,9 @@ export function normalizeToolArguments(
     }
     return parsed
   } catch {
-    if (toolName === 'Bash') {
     if (isBlankString(rawArguments) || isLikelyStructuredObjectLiteral(rawArguments)) {
       return { raw: rawArguments }
     }
-    }
     return (
       wrapPlainStringToolArguments(toolName, rawArguments) ?? { raw: rawArguments }
     )