fix(cliproxy): sanitize invalid tool name chars and disambiguate collisions

sanitizeToolName() fallback now forces valid characters (replaces
unsupported chars with underscores, ensures leading letter/underscore)
instead of only truncating. registerTools() disambiguates colliding
sanitized names with numeric suffixes so restoreToolUse() always maps
back to the correct original.

src/cliproxy/ai-providers/__tests__/tool-name-mapper.test.js

@@ -4,7 +4,7 @@
 
 const assert = require('assert');
 
-const { ToolNameMapper } = require('../../../../dist/cliproxy/tool-name-mapper');
+const { ToolNameMapper } = require('../../../../dist/cliproxy/ai-providers/tool-name-mapper');
 
 describe('Tool Name Mapper', () => {
   describe('registerTools', () => {
@@ -243,4 +243,62 @@ describe('Tool Name Mapper', () => {
       assert.strictEqual(mapper.restoreName('foo__bar'), 'foo__bar');
     });
   });
+
+  describe('collision handling', () => {
+    it('disambiguates when sanitized name collides with unchanged name', () => {
+      const mapper = new ToolNameMapper();
+      // 'abc__def__def' sanitizes to 'abc__def' (changed)
+      // 'abc__def' is unchanged but collides with the sanitized name
+      const tools = [{ name: 'abc__def__def' }, { name: 'abc__def' }];
+
+      const result = mapper.registerTools(tools);
+
+      assert.strictEqual(result[0].name, 'abc__def');
+      assert.strictEqual(result[1].name, 'abc__def_2');
+      assert.strictEqual(mapper.hasCollisions(), true);
+    });
+
+    it('disambiguates different originals that sanitize to the same name', () => {
+      const mapper = new ToolNameMapper();
+      const tools = [{ name: 'abc__def__def' }, { name: 'abc__def' }];
+
+      const result = mapper.registerTools(tools);
+
+      // 'abc__def__def' → 'abc__def' (deduped)
+      // 'abc__def' → 'abc__def_2' (disambiguated, unchanged but collides)
+      assert.strictEqual(result[0].name, 'abc__def');
+      assert.strictEqual(result[1].name, 'abc__def_2');
+    });
+
+    it('restores both colliding tools to correct originals', () => {
+      const mapper = new ToolNameMapper();
+      const tools = [{ name: 'a__b__b' }, { name: 'a__b' }];
+
+      mapper.registerTools(tools);
+
+      const content = [
+        { type: 'tool_use', id: '1', name: 'a__b', input: {} },
+        { type: 'tool_use', id: '2', name: 'a__b_2', input: {} },
+      ];
+
+      const restored = mapper.restoreToolUse(content);
+
+      assert.strictEqual(restored[0].name, 'a__b__b');
+      assert.strictEqual(restored[1].name, 'a__b');
+    });
+
+    it('records collision metadata for logging', () => {
+      const mapper = new ToolNameMapper();
+      const tools = [{ name: 'x__y__y' }, { name: 'x__y' }];
+
+      mapper.registerTools(tools);
+
+      assert.strictEqual(mapper.hasCollisions(), true);
+      const collisions = mapper.getCollisions();
+      assert.strictEqual(collisions.length, 1);
+      assert.strictEqual(collisions[0].base, 'x__y');
+      assert.ok(collisions[0].originals.includes('x__y__y'));
+      assert.ok(collisions[0].originals.includes('x__y'));
+    });
+  });
 });

src/cliproxy/ai-providers/__tests__/tool-name-sanitizer.test.js

@@ -10,7 +10,7 @@ const {
   smartTruncate,
   sanitizeToolName,
   GEMINI_MAX_TOOL_NAME_LENGTH,
-} = require('../../../../dist/cliproxy/tool-name-sanitizer');
+} = require('../../../../dist/cliproxy/ai-providers/tool-name-sanitizer');
 
 describe('Tool Name Sanitizer', () => {
   describe('GEMINI_MAX_TOOL_NAME_LENGTH', () => {
@@ -170,5 +170,38 @@ describe('Tool Name Sanitizer', () => {
       assert.strictEqual(result.changed, true);
       assert.strictEqual(result.sanitized, 'gitmcp__plus-pro-components');
     });
+
+    it('forces valid characters when name contains spaces', () => {
+      const result = sanitizeToolName('has space');
+
+      assert.strictEqual(result.sanitized, 'has_space');
+      assert.strictEqual(result.changed, true);
+      assert.ok(isValidToolName(result.sanitized));
+    });
+
+    it('forces valid characters when name starts with digit', () => {
+      const result = sanitizeToolName('123start');
+
+      assert.ok(result.sanitized.startsWith('_'));
+      assert.strictEqual(result.changed, true);
+      assert.ok(isValidToolName(result.sanitized));
+    });
+
+    it('forces valid characters when name contains symbols', () => {
+      const result = sanitizeToolName('tool@name#here');
+
+      assert.ok(!result.sanitized.includes('@'));
+      assert.ok(!result.sanitized.includes('#'));
+      assert.strictEqual(result.changed, true);
+      assert.ok(isValidToolName(result.sanitized));
+    });
+
+    it('produces valid name for digit-starting long name', () => {
+      const name = '1' + 'a'.repeat(100);
+      const result = sanitizeToolName(name);
+
+      assert.ok(isValidToolName(result.sanitized), `Expected valid name, got: ${result.sanitized}`);
+      assert.ok(result.sanitized.length <= 64);
+    });
   });
 });

src/cliproxy/ai-providers/tool-name-mapper.ts

@@ -41,8 +41,12 @@ export interface SanitizationChange {
 
 /** Record of a hash collision */
 export interface HashCollision {
-  sanitized: string;
+  /** The base sanitized name before disambiguation */
+  base: string;
+  /** All original names that collided */
   originals: string[];
+  /** The sanitized name used (after disambiguation) */
+  sanitized: string;
 }
 
 /**
@@ -63,7 +67,8 @@ export class ToolNameMapper {
 
   /**
    * Register tools and sanitize their names.
-   * Stores mapping for later restoration.
+   * Stores mapping for later restoration. On collision (two originals
+   * sanitizing to the same name), disambiguates with a numeric suffix.
    *
    * @param tools Array of tool definitions
    * @returns Array of tools with sanitized names
@@ -71,36 +76,49 @@ export class ToolNameMapper {
   registerTools(tools: Tool[]): Tool[] {
     return tools.map((tool) => {
       const result: SanitizeResult = sanitizeToolName(tool.name);
+      let finalName = result.sanitized;
 
-      if (result.changed) {
-        // Check for collision: sanitized name already maps to different original
-        const existingOriginal = this.mapping.get(result.sanitized);
-        if (existingOriginal && existingOriginal !== tool.name) {
-          // Record collision
-          const existing = this.collisions.find((c) => c.sanitized === result.sanitized);
-          if (existing) {
-            if (!existing.originals.includes(tool.name)) {
-              existing.originals.push(tool.name);
-            }
-          } else {
-            this.collisions.push({
-              sanitized: result.sanitized,
-              originals: [existingOriginal, tool.name],
-            });
+      // Check for collision regardless of whether the name changed.
+      // An unchanged name can still collide with a previously sanitized name.
+      const existingOriginal = this.mapping.get(finalName);
+      if (existingOriginal && existingOriginal !== tool.name) {
+        // Record collision for logging
+        const existing = this.collisions.find((c) => c.base === finalName);
+        if (existing) {
+          if (!existing.originals.includes(tool.name)) {
+            existing.originals.push(tool.name);
           }
+        } else {
+          this.collisions.push({
+            base: finalName,
+            originals: [existingOriginal, tool.name],
+            sanitized: finalName,
+          });
         }
 
-        // Store mapping: sanitized → original
-        this.mapping.set(result.sanitized, tool.name);
+        // Disambiguate: append _N suffix to make unique
+        let suffix = 2;
+        let disambiguated: string;
+        do {
+          disambiguated = `${finalName}_${suffix}`;
+          suffix++;
+        } while (this.mapping.has(disambiguated) && this.mapping.get(disambiguated) !== tool.name);
+
+        finalName = disambiguated;
+      }
+
+      // Store mapping if name changed or was disambiguated
+      if (finalName !== tool.name) {
+        this.mapping.set(finalName, tool.name);
         this.changes.push({
           original: tool.name,
-          sanitized: result.sanitized,
+          sanitized: finalName,
         });
       }
 
       return {
         ...tool,
-        name: result.sanitized,
+        name: finalName,
       };
     });
   }

src/cliproxy/ai-providers/tool-name-sanitizer.ts

@@ -100,13 +100,34 @@ export function smartTruncate(name: string, maxLen: number = GEMINI_MAX_TOOL_NAM
   return `${prefix}_${hash}`;
 }
 
+/**
+ * Force a string to comply with Gemini tool name character rules.
+ * Replaces invalid characters with underscores and ensures the name
+ * starts with a letter or underscore.
+ */
+function forceValidChars(name: string): string {
+  // Replace any character not in [a-zA-Z0-9_.:/-] with underscore
+  let fixed = name.replace(/[^a-zA-Z0-9_.:/-]/g, '_');
+
+  // Collapse multiple consecutive underscores from replacement
+  fixed = fixed.replace(/_+/g, '_');
+
+  // Ensure starts with letter or underscore
+  if (fixed.length > 0 && /^[0-9]/.test(fixed)) {
+    fixed = '_' + fixed;
+  }
+
+  return fixed || '_';
+}
+
 /**
  * Sanitize a tool name to comply with Gemini API constraints.
  *
  * Process:
  * 1. Remove duplicate segments (always, as duplicates are likely unintentional)
  * 2. Truncate with hash if >64 chars
- * 3. Return result with changed flag
+ * 3. Force valid characters if still invalid
+ * 4. Truncate again if forced-valid name exceeds limit
  *
  * @param name The original tool name
  * @returns Sanitization result with sanitized name and changed flag
@@ -121,9 +142,12 @@ export function sanitizeToolName(name: string): SanitizeResult {
     sanitized = smartTruncate(sanitized);
   }
 
-  // Step 3: If still invalid after sanitization, apply truncation to original
+  // Step 3: If still invalid, fix characters and truncate if needed
   if (!isValidToolName(sanitized)) {
-    sanitized = smartTruncate(name);
+    sanitized = forceValidChars(sanitized);
+    if (sanitized.length > GEMINI_MAX_TOOL_NAME_LENGTH) {
+      sanitized = smartTruncate(sanitized);
+    }
   }
 
   return {