Python: Adding AgentFileStore and FileAccessProvider to support file access operations.

python/packages/core/AGENTS.md

@@ -76,6 +76,14 @@ agent_framework/
 - **`SkillScriptRunner`** - Protocol for file-based script execution. Any callable matching `(skill, script, args) -> Any` satisfies it. Code-defined scripts do not use a runner.
 - **`SkillsProvider`** - Context provider (extends `ContextProvider`) that discovers file-based skills from `SKILL.md` files and/or accepts code-defined `Skill` instances. Follows progressive disclosure: advertise → load → read resources / run scripts.
 
+### File Access Harness (`_harness/_file_access.py`)
+
+- **`AgentFileStore`** - Abstract async store backing the file-access harness. Implementations expose `write_file`, `read_file`, `delete_file`, `list_files`, `file_exists`, `search_files`, and `create_directory` over forward-slash relative paths.
+- **`InMemoryAgentFileStore`** - Dict-backed store suitable for tests and lightweight scenarios.
+- **`FileSystemAgentFileStore`** - Disk-backed store rooted under a configurable directory. Enforces relative-path normalization, root containment, and rejects symlink/reparse-point segments to prevent escape.
+- **`FileSearchResult`** / **`FileSearchMatch`** - `SerializationMixin` DTOs returned by `search_files`, carrying the matching file name, a context snippet, and the matching lines with 1-based line numbers.
+- **`FileAccessProvider`** - `ContextProvider` that adds shared file-access tools (`file_access_save_file`, `file_access_read_file`, `file_access_delete_file`, `file_access_list_files`, `file_access_search_files`) plus default usage instructions to each invocation. Unlike `MemoryContextProvider`, the store is intentionally shared across sessions and agents.
+
 ### Workflows (`_workflows/`)
 
 - **`Workflow`** - Graph-based workflow definition

python/packages/core/agent_framework/__init__.py

@@ -79,6 +79,16 @@
     tool_calls_present,
 )
 from ._feature_stage import ExperimentalFeature, ReleaseCandidateFeature
+from ._harness._file_access import (
+    DEFAULT_FILE_ACCESS_INSTRUCTIONS,
+    DEFAULT_FILE_ACCESS_SOURCE_ID,
+    AgentFileStore,
+    FileAccessProvider,
+    FileSearchMatch,
+    FileSearchResult,
+    FileSystemAgentFileStore,
+    InMemoryAgentFileStore,
+)
 from ._harness._memory import (
     DEFAULT_MEMORY_SOURCE_ID,
     MemoryContextProvider,
@@ -297,6 +307,8 @@
     "AGENT_FRAMEWORK_USER_AGENT",
     "APP_INFO",
     "COMPACTION_STATE_KEY",
+    "DEFAULT_FILE_ACCESS_INSTRUCTIONS",
+    "DEFAULT_FILE_ACCESS_SOURCE_ID",
     "DEFAULT_MAX_ITERATIONS",
     "DEFAULT_MEMORY_SOURCE_ID",
     "DEFAULT_MODE_SOURCE_ID",
@@ -321,6 +333,7 @@
     "AgentExecutor",
     "AgentExecutorRequest",
     "AgentExecutorResponse",
+    "AgentFileStore",
     "AgentFrameworkException",
     "AgentMiddleware",
     "AgentMiddlewareLayer",
@@ -376,11 +389,15 @@
     "ExperimentalFeature",
     "FanInEdgeGroup",
     "FanOutEdgeGroup",
+    "FileAccessProvider",
     "FileCheckpointStorage",
     "FileHistoryProvider",
+    "FileSearchMatch",
+    "FileSearchResult",
     "FileSkill",
     "FileSkillScript",
     "FileSkillsSource",
+    "FileSystemAgentFileStore",
     "FilteringSkillsSource",
     "FinalT",
     "FinishReason",
@@ -397,6 +414,7 @@
     "GeneratedEmbeddings",
     "GraphConnectivityError",
     "HistoryProvider",
+    "InMemoryAgentFileStore",
     "InMemoryCheckpointStorage",
     "InMemoryHistoryProvider",
     "InMemorySkillsSource",