diff --git a/apps/studio/src/mocks/createKernel.ts b/apps/studio/src/mocks/createKernel.ts
index d0f17a8169..5f86b4ca30 100644
--- a/apps/studio/src/mocks/createKernel.ts
+++ b/apps/studio/src/mocks/createKernel.ts
@@ -124,7 +124,7 @@ export async function createKernel(options: KernelOptions) {
                     
                     if (!all) all = [];
 
-                    const filters = params.filters;
+                    const filters = params.query || params.filters;
                     // Extract standard query options possibly passed via filters (due to MSW plugin mapping)
                     let queryOptions: any = {};
                     if (filters && typeof filters === 'object') {
diff --git a/packages/client/src/client.msw.test.ts b/packages/client/src/client.msw.test.ts
index 40ccf819c1..7d11a4a276 100644
--- a/packages/client/src/client.msw.test.ts
+++ b/packages/client/src/client.msw.test.ts
@@ -48,11 +48,13 @@ describe('ObjectStackClient (with MSW Plugin)', () => {
                         return record ? { object: params.object, id: params.id, record } : null;
                     }
                     if (method === 'query') {
-                        const records = await ql.find(params.object, { filter: params.filters });
+                        const queryOpts = params.query || {};
+                        const records = await ql.find(params.object, { filter: queryOpts.filters || queryOpts.filter });
                         return { object: params.object, records, total: records.length };
                     }
                     if (method === 'find') {
-                        const records = await ql.find(params.object, { filter: params.filters });
+                        const queryOpts = params.query || {};
+                        const records = await ql.find(params.object, { filter: queryOpts.filters || queryOpts.filter });
                         return { object: params.object, records, total: records.length };
                     }
                 }
diff --git a/packages/objectql/src/protocol.ts b/packages/objectql/src/protocol.ts
index 889c16adfe..cbb1803629 100644
--- a/packages/objectql/src/protocol.ts
+++ b/packages/objectql/src/protocol.ts
@@ -10,6 +10,7 @@ import type {
 } from '@objectstack/spec/api';
 import type { MetadataCacheRequest, MetadataCacheResponse, ServiceInfo, ApiRoutes, WellKnownCapabilities } from '@objectstack/spec/api';
 import type { IFeedService } from '@objectstack/spec/contracts';
+import { parseFilterAST } from '@objectstack/spec/data';
 
 // We import SchemaRegistry directly since this class lives in the same package
 import { SchemaRegistry } from './registry.js';
@@ -311,6 +312,12 @@ export class ObjectStackProtocolImplementation implements ObjectStackProtocol {
             try { options.filter = JSON.parse(options.filters); delete options.filters; } catch { /* keep as-is */ }
         }
 
+        // Filter AST array → FilterCondition object
+        // Converts ["and", ["field", "=", "val"], ...] to { $and: [{ field: "val" }, ...] }
+        if (Array.isArray(options.filter)) {
+            options.filter = parseFilterAST(options.filter);
+        }
+
         // Populate: comma-separated string → array
         if (typeof options.populate === 'string') {
             options.populate = options.populate.split(',').map((s: string) => s.trim()).filter(Boolean);
diff --git a/packages/runtime/src/http-dispatcher.ts b/packages/runtime/src/http-dispatcher.ts
index 9bf4a3d4da..93221ea5b6 100644
--- a/packages/runtime/src/http-dispatcher.ts
+++ b/packages/runtime/src/http-dispatcher.ts
@@ -401,7 +401,7 @@ export class HttpDispatcher {
             // GET /data/:object (List)
             if (m === 'GET') {
                 // Spec: broker returns FindDataResponse = { object, records, total?, hasMore? }
-                const result = await broker.call('data.query', { object: objectName, filters: query }, { request: context.request });
+                const result = await broker.call('data.query', { object: objectName, query }, { request: context.request });
                 return { handled: true, response: this.success(result) };
             }
 
@@ -941,7 +941,7 @@ export class HttpDispatcher {
                         const { object, operation } = endpoint.objectParams;
                         // Map standard CRUD operations
                         if (operation === 'find') {
-                             const result = await broker.call('data.query', { object, filters: query }, { request: context.request });
+                             const result = await broker.call('data.query', { object, query }, { request: context.request });
                              return { handled: true, response: this.success(result.data, { count: result.count }) };
                         }
                         if (operation === 'get' && query.id) {
diff --git a/packages/spec/src/data/filter.test.ts b/packages/spec/src/data/filter.test.ts
index dae2a1476e..3ec7034d15 100644
--- a/packages/spec/src/data/filter.test.ts
+++ b/packages/spec/src/data/filter.test.ts
@@ -13,6 +13,7 @@ import {
   FILTER_OPERATORS,
   LOGICAL_OPERATORS,
   ALL_OPERATORS,
+  parseFilterAST,
   type Filter,
   type QueryFilter,
   type FieldOperators,
@@ -753,3 +754,170 @@ describe('NormalizedFilterSchema', () => {
     expect(() => NormalizedFilterSchema.parse(filter)).not.toThrow();
   });
 });
+
+// ============================================================================
+// parseFilterAST Tests
+// ============================================================================
+
+describe('parseFilterAST', () => {
+  it('should return undefined for null/undefined input', () => {
+    expect(parseFilterAST(null)).toBeUndefined();
+    expect(parseFilterAST(undefined)).toBeUndefined();
+  });
+
+  it('should return undefined for empty array', () => {
+    expect(parseFilterAST([])).toBeUndefined();
+  });
+
+  it('should pass through object filters as-is', () => {
+    const filter = { status: 'active' };
+    expect(parseFilterAST(filter)).toEqual({ status: 'active' });
+  });
+
+  it('should pass through FilterCondition with $and/$or as-is', () => {
+    const filter = { $and: [{ priority: 'high' }, { status: 'active' }] };
+    expect(parseFilterAST(filter)).toEqual(filter);
+  });
+
+  it('should convert simple equality comparison', () => {
+    expect(parseFilterAST(['status', '=', 'active'])).toEqual({ status: 'active' });
+  });
+
+  it('should convert == equality comparison', () => {
+    expect(parseFilterAST(['status', '==', 'active'])).toEqual({ status: 'active' });
+  });
+
+  it('should convert != comparison', () => {
+    expect(parseFilterAST(['status', '!=', 'deleted'])).toEqual({ status: { $ne: 'deleted' } });
+  });
+
+  it('should convert <> comparison', () => {
+    expect(parseFilterAST(['status', '<>', 'deleted'])).toEqual({ status: { $ne: 'deleted' } });
+  });
+
+  it('should convert > comparison', () => {
+    expect(parseFilterAST(['age', '>', 18])).toEqual({ age: { $gt: 18 } });
+  });
+
+  it('should convert >= comparison', () => {
+    expect(parseFilterAST(['age', '>=', 18])).toEqual({ age: { $gte: 18 } });
+  });
+
+  it('should convert < comparison', () => {
+    expect(parseFilterAST(['age', '<', 65])).toEqual({ age: { $lt: 65 } });
+  });
+
+  it('should convert <= comparison', () => {
+    expect(parseFilterAST(['age', '<=', 65])).toEqual({ age: { $lte: 65 } });
+  });
+
+  it('should convert in operator', () => {
+    expect(parseFilterAST(['role', 'in', ['admin', 'editor']])).toEqual({ role: { $in: ['admin', 'editor'] } });
+  });
+
+  it('should convert not_in operator', () => {
+    expect(parseFilterAST(['role', 'not_in', ['guest']])).toEqual({ role: { $nin: ['guest'] } });
+  });
+
+  it('should convert contains/like operator', () => {
+    expect(parseFilterAST(['name', 'contains', 'John'])).toEqual({ name: { $contains: 'John' } });
+    expect(parseFilterAST(['name', 'like', 'John'])).toEqual({ name: { $contains: 'John' } });
+  });
+
+  it('should convert startswith operator', () => {
+    expect(parseFilterAST(['name', 'startswith', 'A'])).toEqual({ name: { $startsWith: 'A' } });
+    expect(parseFilterAST(['name', 'starts_with', 'A'])).toEqual({ name: { $startsWith: 'A' } });
+  });
+
+  it('should convert endswith operator', () => {
+    expect(parseFilterAST(['name', 'endswith', '.pdf'])).toEqual({ name: { $endsWith: '.pdf' } });
+    expect(parseFilterAST(['name', 'ends_with', '.pdf'])).toEqual({ name: { $endsWith: '.pdf' } });
+  });
+
+  it('should convert between operator', () => {
+    expect(parseFilterAST(['age', 'between', [18, 65]])).toEqual({ age: { $between: [18, 65] } });
+  });
+
+  it('should convert nin operator (MongoDB alias)', () => {
+    expect(parseFilterAST(['role', 'nin', ['guest']])).toEqual({ role: { $nin: ['guest'] } });
+  });
+
+  it('should convert is_null operator', () => {
+    expect(parseFilterAST(['deleted_at', 'is_null', null])).toEqual({ deleted_at: { $null: true } });
+  });
+
+  it('should convert is_not_null operator', () => {
+    expect(parseFilterAST(['deleted_at', 'is_not_null', null])).toEqual({ deleted_at: { $null: false } });
+  });
+
+  it('should convert AND logical node', () => {
+    const input = ['and', ['priority', '=', 'high'], ['status', '=', 'active']];
+    expect(parseFilterAST(input)).toEqual({
+      $and: [{ priority: 'high' }, { status: 'active' }],
+    });
+  });
+
+  it('should convert OR logical node', () => {
+    const input = ['or', ['role', '=', 'admin'], ['role', '=', 'editor']];
+    expect(parseFilterAST(input)).toEqual({
+      $or: [{ role: 'admin' }, { role: 'editor' }],
+    });
+  });
+
+  it('should handle nested logical operators', () => {
+    const input = ['and', ['status', '=', 'active'], ['or', ['priority', '=', 'high'], ['priority', '=', 'critical']]];
+    expect(parseFilterAST(input)).toEqual({
+      $and: [
+        { status: 'active' },
+        { $or: [{ priority: 'high' }, { priority: 'critical' }] },
+      ],
+    });
+  });
+
+  it('should unwrap single-child logical nodes', () => {
+    const input = ['and', ['status', '=', 'active']];
+    expect(parseFilterAST(input)).toEqual({ status: 'active' });
+  });
+
+  it('should handle case-insensitive logical operators', () => {
+    const input = ['AND', ['status', '=', 'active'], ['priority', '=', 'high']];
+    expect(parseFilterAST(input)).toEqual({
+      $and: [{ status: 'active' }, { priority: 'high' }],
+    });
+  });
+
+  it('should handle legacy flat array of conditions', () => {
+    const input = [['status', '=', 'active'], ['priority', '=', 'high']];
+    expect(parseFilterAST(input)).toEqual({
+      $and: [{ status: 'active' }, { priority: 'high' }],
+    });
+  });
+
+  it('should handle real-world browser filter example from issue', () => {
+    const input = ['and', ['priority', '=', 'high'], ['status', '=', 'active']];
+    const result = parseFilterAST(input);
+    expect(result).toEqual({
+      $and: [{ priority: 'high' }, { status: 'active' }],
+    });
+    // Validate the result is a valid FilterCondition
+    expect(() => FilterConditionSchema.parse(result)).not.toThrow();
+  });
+
+  it('should produce valid FilterCondition for complex nested AST', () => {
+    const input = [
+      'and',
+      ['status', '!=', 'deleted'],
+      ['or', ['priority', '=', 'high'], ['age', '>', 18]],
+      ['role', 'in', ['admin', 'editor']],
+    ];
+    const result = parseFilterAST(input);
+    expect(result).toEqual({
+      $and: [
+        { status: { $ne: 'deleted' } },
+        { $or: [{ priority: 'high' }, { age: { $gt: 18 } }] },
+        { role: { $in: ['admin', 'editor'] } },
+      ],
+    });
+    expect(() => FilterConditionSchema.parse(result)).not.toThrow();
+  });
+});
diff --git a/packages/spec/src/data/filter.zod.ts b/packages/spec/src/data/filter.zod.ts
index 714795a71a..9bc9424e24 100644
--- a/packages/spec/src/data/filter.zod.ts
+++ b/packages/spec/src/data/filter.zod.ts
@@ -335,6 +335,124 @@ export const NormalizedFilterSchema: z.ZodType<any> = z.lazy(() =>
 
 export type NormalizedFilter = z.infer<typeof NormalizedFilterSchema>;
 
+// ============================================================================
+// AST Array → FilterCondition Conversion
+// ============================================================================
+
+/**
+ * Operator mapping from AST infix operators to FilterCondition `$`-prefixed operators.
+ */
+const AST_OPERATOR_MAP: Record<string, string> = {
+  '=': '$eq',
+  '==': '$eq',
+  '!=': '$ne',
+  '<>': '$ne',
+  '>': '$gt',
+  '>=': '$gte',
+  '<': '$lt',
+  '<=': '$lte',
+  'in': '$in',
+  'nin': '$nin',
+  'not_in': '$nin',
+  'contains': '$contains',
+  'like': '$contains',
+  'startswith': '$startsWith',
+  'starts_with': '$startsWith',
+  'endswith': '$endsWith',
+  'ends_with': '$endsWith',
+  'between': '$between',
+  'is_null': '$null',
+  'is_not_null': '$null',
+};
+
+/**
+ * Convert a single AST comparison node `[field, operator, value]` to a FilterCondition object.
+ */
+function convertComparison(node: [string, string, unknown]): FilterCondition {
+  const [field, operator, value] = node;
+  const op = operator.toLowerCase();
+
+  // Special case: equality shorthand
+  if (op === '=' || op === '==') {
+    return { [field]: value } as FilterCondition;
+  }
+
+  // Null check operators
+  if (op === 'is_null') {
+    return { [field]: { $null: true } } as FilterCondition;
+  }
+  if (op === 'is_not_null') {
+    return { [field]: { $null: false } } as FilterCondition;
+  }
+
+  const mapped = AST_OPERATOR_MAP[op];
+  if (mapped) {
+    return { [field]: { [mapped]: value } } as FilterCondition;
+  }
+
+  // Fallback: use the operator as-is with $ prefix
+  return { [field]: { [`$${op}`]: value } } as FilterCondition;
+}
+
+/**
+ * Parse a filter from AST array format to FilterCondition object format.
+ *
+ * The AST array format is used by the ObjectUI client and the `FilterBuilder`:
+ * - Comparison: `[field, operator, value]` → `{ field: value }` or `{ field: { $op: value } }`
+ * - Logical AND: `["and", cond1, cond2, ...]` → `{ $and: [...] }`
+ * - Logical OR: `["or", cond1, cond2, ...]` → `{ $or: [...] }`
+ *
+ * If the input is already a FilterCondition object (not an array), it is returned as-is.
+ * If the input is `null` or `undefined`, it is returned as-is.
+ *
+ * @example
+ * // Simple condition
+ * parseFilterAST(["status", "=", "active"])
+ * // → { status: "active" }
+ *
+ * @example
+ * // Compound AND
+ * parseFilterAST(["and", ["priority", "=", "high"], ["status", "=", "active"]])
+ * // → { $and: [{ priority: "high" }, { status: "active" }] }
+ *
+ * @example
+ * // Object passthrough
+ * parseFilterAST({ status: "active" })
+ * // → { status: "active" }
+ */
+export function parseFilterAST(filter: unknown): FilterCondition | undefined {
+  if (filter == null) return undefined;
+  if (!Array.isArray(filter)) return filter as FilterCondition;
+  if (filter.length === 0) return undefined;
+
+  const first = filter[0];
+
+  // Logical node: ["and", cond1, cond2, ...] or ["or", cond1, cond2, ...]
+  if (typeof first === 'string' && (first.toLowerCase() === 'and' || first.toLowerCase() === 'or')) {
+    const logicOp = `$${first.toLowerCase()}` as '$and' | '$or';
+    const children = filter.slice(1).map((child: unknown) => parseFilterAST(child)).filter(Boolean) as FilterCondition[];
+    if (children.length === 0) return undefined;
+    if (children.length === 1) return children[0];
+    return { [logicOp]: children } as FilterCondition;
+  }
+
+  // Comparison node: [field, operator, value]
+  if (filter.length >= 2 && typeof first === 'string') {
+    return convertComparison(filter as [string, string, unknown]);
+  }
+
+  // Legacy flat array: [[field, op, val], [field, op, val], ...]
+  // All elements are sub-arrays → treat as implicit AND
+  if (filter.every((item: unknown) => Array.isArray(item))) {
+    const children = filter.map((child: unknown) => parseFilterAST(child)).filter(Boolean) as FilterCondition[];
+    if (children.length === 0) return undefined;
+    if (children.length === 1) return children[0];
+    return { $and: children } as FilterCondition;
+  }
+
+  return undefined;
+}
+
 // ============================================================================
 // Constants & Metadata
 // ============================================================================