diff --git a/AGENTS.md b/AGENTS.md
index 9aae7e66..234d60ac 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -66,13 +66,14 @@ Configured in `agent/server.py:get_agent`, runs around every model call (in this
 1. `SanitizeToolInputsMiddleware` — strips/normalizes tool inputs before they reach tools.
 2. `ModelCallLimitMiddleware` (from `langchain.agents.middleware`) — caps model calls at `MODEL_CALL_RECURSION_LIMIT` (~half of `DEFAULT_RECURSION_LIMIT`); `exit_behavior="end"`.
 3. `ToolErrorMiddleware` — catches tool exceptions and surfaces them as tool messages.
-4. `check_message_queue_before_model` — pulls Linear comments / Slack messages that arrived mid-run from the thread queue and injects them as user messages before the next LLM call. This is what makes "message the agent while it's working" work.
-5. `SlackAssistantStatusMiddleware` — keeps the Slack "assistant is typing"-style status up to date around model calls.
-6. `ensure_no_empty_msg` — after-model hook; when the model emits a message with no tool call (and hasn't already messaged the user or confirmed completion) it re-injects a synthetic `no_op` / `confirming_completion` tool call so the run continues instead of ending prematurely.
-7. `notify_step_limit_reached` — after-agent hook that posts a Slack reply when the agent hits the step limit, so the user gets a clear signal instead of silence.
-8. `SandboxCircuitBreakerMiddleware` — trips the agent out of repeated sandbox failures instead of looping.
-9. `ModelFallbackMiddleware` (optional) — added only when `LLM_FALLBACK_MODEL_ID` or the per-model default fallback differs from the primary model.
-10. `SanitizeThinkingBlocksMiddleware` — strips malformed empty Anthropic thinking blocks immediately before provider calls.
+4. `SubdirAgentsReadMiddleware` — appends applicable ancestor `AGENTS.md` instructions to `read_file` results once per run, so scoped rules are visible before edits.
+5. `check_message_queue_before_model` — pulls Linear comments / Slack messages that arrived mid-run from the thread queue and injects them as user messages before the next LLM call. This is what makes "message the agent while it's working" work.
+6. `SlackAssistantStatusMiddleware` — keeps the Slack "assistant is typing"-style status up to date around model calls.
+7. `ensure_no_empty_msg` — after-model hook; when the model emits a message with no tool call (and hasn't already messaged the user or confirmed completion) it re-injects a synthetic `no_op` / `confirming_completion` tool call so the run continues instead of ending prematurely.
+8. `notify_step_limit_reached` — after-agent hook that posts a Slack reply when the agent hits the step limit, so the user gets a clear signal instead of silence.
+9. `SandboxCircuitBreakerMiddleware` — trips the agent out of repeated sandbox failures instead of looping.
+10. `ModelFallbackMiddleware` (optional) — added only when `LLM_FALLBACK_MODEL_ID` or the per-model default fallback differs from the primary model.
+11. `SanitizeThinkingBlocksMiddleware` — strips malformed empty Anthropic thinking blocks immediately before provider calls.
 
 The system prompt instructs the agent to call a tool every turn, and `ensure_no_empty_msg` re-injects a tool call when it doesn't — together these keep runs from stopping partway through a task.
 
diff --git a/agent/middleware/__init__.py b/agent/middleware/__init__.py
index 02c55d80..c40ce67b 100644
--- a/agent/middleware/__init__.py
+++ b/agent/middleware/__init__.py
@@ -11,6 +11,7 @@ from .sandbox_circuit_breaker import SandboxCircuitBreakerMiddleware
 from .sanitize_thinking_blocks import SanitizeThinkingBlocksMiddleware
 from .sanitize_tool_inputs import SanitizeToolInputsMiddleware
 from .settle_review_check import settle_review_check_on_exit
+from .subdir_agents import SubdirAgentsReadMiddleware
 from .tool_artifact import ToolArtifactMiddleware
 from .tool_error_handler import ToolErrorMiddleware
 from .workflow_push_guard import WorkflowPushGuardMiddleware
@@ -22,6 +23,7 @@ __all__ = [
     "RepairOrphanedToolCallsMiddleware",
     "SanitizeThinkingBlocksMiddleware",
     "SanitizeToolInputsMiddleware",
+    "SubdirAgentsReadMiddleware",
     "ToolArtifactMiddleware",
     "ToolErrorMiddleware",
     "WorkflowPushGuardMiddleware",
diff --git a/agent/middleware/subdir_agents.py b/agent/middleware/subdir_agents.py
new file mode 100644
index 00000000..e4a65242
--- /dev/null
+++ b/agent/middleware/subdir_agents.py
@@ -0,0 +1,197 @@
+"""Auto-load applicable ``AGENTS.md`` files after file reads."""
+
+from __future__ import annotations
+
+import logging
+import posixpath
+from collections import defaultdict
+from collections.abc import Awaitable, Callable, Iterable, Mapping
+from typing import Any
+
+from langchain.agents.middleware.types import AgentMiddleware, AgentState
+from langchain_core.messages import ToolMessage
+from langgraph.config import get_config
+from langgraph.prebuilt.tool_node import ToolCallRequest
+from langgraph.types import Command
+
+from ..utils.sandbox_state import SANDBOX_BACKENDS
+
+logger = logging.getLogger(__name__)
+
+_READ_FILE = "read_file"
+_AGENTS_MD = "AGENTS.md"
+_MAX_AGENTS_LINES = 1_000
+_MAX_AGENTS_BYTES = 64 * 1024
+
+
+def _tool_name(request: ToolCallRequest) -> str | None:
+    tool_call = getattr(request, "tool_call", None)
+    if isinstance(tool_call, Mapping):
+        name = tool_call.get("name")
+        return name if isinstance(name, str) and name else None
+    return None
+
+
+def _tool_args(request: ToolCallRequest) -> dict[str, Any]:
+    tool_call = getattr(request, "tool_call", None)
+    if isinstance(tool_call, Mapping):
+        args = tool_call.get("args")
+        if isinstance(args, Mapping):
+            return dict(args)
+    return {}
+
+
+def _thread_id(request: ToolCallRequest) -> str | None:
+    runtime_config = getattr(getattr(request, "runtime", None), "config", None)
+    config: Mapping[str, Any] | None = (
+        runtime_config if isinstance(runtime_config, Mapping) else None
+    )
+    if config is None:
+        try:
+            maybe_config = get_config()
+        except Exception:
+            return None
+        config = maybe_config if isinstance(maybe_config, Mapping) else None
+    if config is None:
+        return None
+    configurable = config.get("configurable", {})
+    if not isinstance(configurable, Mapping):
+        return None
+    thread_id = configurable.get("thread_id")
+    return thread_id if isinstance(thread_id, str) and thread_id else None
+
+
+def _file_path(args: Mapping[str, Any]) -> str | None:
+    raw = args.get("file_path")
+    if not isinstance(raw, str):
+        return None
+    path = raw.strip()
+    if not path.startswith("/"):
+        return None
+    return posixpath.normpath(path)
+
+
+def _candidate_agents_paths(file_path: str) -> list[str]:
+    current = posixpath.dirname(file_path)
+    candidates: list[str] = []
+    while current and current != "/":
+        candidates.append(posixpath.join(current, _AGENTS_MD))
+        parent = posixpath.dirname(current)
+        if parent == current:
+            break
+        current = parent
+    candidates.reverse()
+    return [candidate for candidate in candidates if candidate != file_path]
+
+
+def _extract_text(result: Any) -> str | None:
+    error = getattr(result, "error", None)
+    if error:
+        return None
+
+    file_data = getattr(result, "file_data", None)
+    if file_data is None:
+        return None
+
+    if isinstance(file_data, Mapping):
+        encoding = file_data.get("encoding")
+        content = file_data.get("content")
+    else:
+        encoding = getattr(file_data, "encoding", None)
+        content = getattr(file_data, "content", None)
+
+    if encoding is not None and encoding != "utf-8":
+        return None
+    if not isinstance(content, str) or not content.strip():
+        return None
+
+    encoded = content.encode("utf-8")
+    if len(encoded) <= _MAX_AGENTS_BYTES:
+        return content
+    return encoded[:_MAX_AGENTS_BYTES].decode("utf-8", errors="ignore") + "\n\n[truncated]"
+
+
+def _system_reminder(file_path: str, loaded: Iterable[tuple[str, str]]) -> str:
+    sections = [f"Instructions from: {path}\n{content.rstrip()}" for path, content in loaded]
+    body = "\n\n".join(sections)
+    return (
+        "<system-reminder>\n"
+        f"Loaded applicable AGENTS.md instructions for `{file_path}`. "
+        "Follow these before editing files under their scopes; more deeply nested "
+        "instructions take precedence.\n\n"
+        f"{body}\n"
+        "</system-reminder>"
+    )
+
+
+def _can_append_reminder(result: ToolMessage | Command) -> bool:
+    return (
+        isinstance(result, ToolMessage)
+        and getattr(result, "status", None) != "error"
+        and isinstance(result.content, str)
+    )
+
+
+def _append_reminder(result: ToolMessage | Command, reminder: str | None) -> ToolMessage | Command:
+    if reminder is not None and _can_append_reminder(result):
+        result.content = f"{result.content}\n\n{reminder}"
+    return result
+
+
+class SubdirAgentsReadMiddleware(AgentMiddleware):
+    """Append applicable ancestor ``AGENTS.md`` files to ``read_file`` results."""
+
+    state_schema = AgentState
+
+    def __init__(self) -> None:
+        self._loaded: defaultdict[str, set[str]] = defaultdict(set)
+
+    def _thread_key(self, request: ToolCallRequest) -> str:
+        return _thread_id(request) or "__unknown_thread__"
+
+    def _backend(self, request: ToolCallRequest) -> Any | None:
+        thread_id = _thread_id(request)
+        if not thread_id:
+            return None
+        return SANDBOX_BACKENDS.get(thread_id)
+
+    def _mark_direct_agents_read(self, request: ToolCallRequest, file_path: str) -> bool:
+        if posixpath.basename(file_path) != _AGENTS_MD:
+            return False
+        self._loaded[self._thread_key(request)].add(file_path)
+        return True
+
+    async def _load_async(self, request: ToolCallRequest, file_path: str) -> str | None:
+        if self._mark_direct_agents_read(request, file_path):
+            return None
+        backend = self._backend(request)
+        if backend is None:
+            return None
+        loaded_paths = self._loaded[self._thread_key(request)]
+        loaded: list[tuple[str, str]] = []
+        for path in _candidate_agents_paths(file_path):
+            if path in loaded_paths:
+                continue
+            loaded_paths.add(path)
+            try:
+                text = _extract_text(await backend.aread(path, offset=0, limit=_MAX_AGENTS_LINES))
+            except Exception:
+                logger.debug("subdir_agents: aread failed for %s", path, exc_info=True)
+                continue
+            if text is None:
+                continue
+            loaded.append((path, text))
+        return _system_reminder(file_path, loaded) if loaded else None
+
+    async def awrap_tool_call(
+        self,
+        request: ToolCallRequest,
+        handler: Callable[[ToolCallRequest], Awaitable[ToolMessage | Command]],
+    ) -> ToolMessage | Command:
+        if _tool_name(request) != _READ_FILE:
+            return await handler(request)
+        result = await handler(request)
+        file_path = _file_path(_tool_args(request))
+        if file_path is None or not _can_append_reminder(result):
+            return result
+        return _append_reminder(result, await self._load_async(request, file_path))
diff --git a/agent/server.py b/agent/server.py
index 37de7367..48afa4d0 100644
--- a/agent/server.py
+++ b/agent/server.py
@@ -61,6 +61,7 @@ from .middleware import (
     SanitizeThinkingBlocksMiddleware,
     SanitizeToolInputsMiddleware,
     SlackAssistantStatusMiddleware,
+    SubdirAgentsReadMiddleware,
     ToolArtifactMiddleware,
     ToolErrorMiddleware,
     WorkflowPushGuardMiddleware,
@@ -82,6 +83,7 @@ from .tools import (
     linear_list_teams,
     linear_update_issue,
     open_pull_request,
+    report_platform_issue,
     request_pr_review,
     save_plan,
     schedule_thread_wakeup,
@@ -957,6 +959,7 @@ async def get_agent(config: RunnableConfig) -> Pregel:
             linear_update_issue,
             open_pull_request,
             request_pr_review,
+            report_platform_issue,
             schedule_thread_wakeup,
             slack_add_reaction,
             slack_read_thread_messages,
@@ -973,6 +976,7 @@ async def get_agent(config: RunnableConfig) -> Pregel:
             SanitizeToolInputsMiddleware(),
             ModelCallLimitMiddleware(run_limit=MODEL_CALL_RECURSION_LIMIT, exit_behavior="end"),
             ToolErrorMiddleware(),
+            SubdirAgentsReadMiddleware(),
             ToolArtifactMiddleware(),
             WorkflowPushGuardMiddleware(),
             refresh_github_proxy_before_model,
diff --git a/agent/tools/__init__.py b/agent/tools/__init__.py
index 96aa85d0..8642474d 100644
--- a/agent/tools/__init__.py
+++ b/agent/tools/__init__.py
@@ -15,6 +15,7 @@ from .open_pull_request import open_pull_request
 from .publish_review import publish_review
 from .read_repo_file import read_repo_file
 from .reply_to_finding_thread import reply_to_finding_thread
+from .report_platform_issue import report_platform_issue
 from .request_pr_review import request_pr_review
 from .resolve_finding_thread import resolve_finding_thread
 from .save_plan import save_plan
@@ -44,6 +45,7 @@ __all__ = [
     "open_pull_request",
     "publish_review",
     "read_repo_file",
+    "report_platform_issue",
     "request_pr_review",
     "reply_to_finding_thread",
     "resolve_finding_thread",
diff --git a/agent/tools/report_platform_issue.py b/agent/tools/report_platform_issue.py
new file mode 100644
index 00000000..8d5afee9
--- /dev/null
+++ b/agent/tools/report_platform_issue.py
@@ -0,0 +1,16 @@
+import secrets
+import time
+import uuid
+
+
+def _uuid7() -> str:
+    timestamp_ms = (time.time_ns() // 1_000_000) & ((1 << 48) - 1)
+    rand_a = secrets.randbits(12)
+    rand_b = secrets.randbits(62)
+    uuid_int = (timestamp_ms << 80) | (0x7 << 76) | (rand_a << 64) | (0b10 << 62) | rand_b
+    return str(uuid.UUID(int=uuid_int))
+
+
+async def report_platform_issue() -> dict[str, str]:
+    """Report an issue with the sandbox or execution environment."""
+    return {"report_id": _uuid7()}
diff --git a/tests/test_agent_assembly_context.py b/tests/test_agent_assembly_context.py
index fa1cb237..43668bf5 100644
--- a/tests/test_agent_assembly_context.py
+++ b/tests/test_agent_assembly_context.py
@@ -92,6 +92,16 @@ async def test_agent_does_not_add_custom_repair_middleware() -> None:
     assert "RepairOrphanedToolCallsMiddleware" not in names
 
 
+@pytest.mark.asyncio
+async def test_agent_wires_subdir_agents_middleware_after_tool_error() -> None:
+    captured = await _capture_create_deep_agent_kwargs()
+    middleware = captured["middleware"]
+    assert isinstance(middleware, list)
+    names = [type(m).__name__ for m in middleware]
+    assert "SubdirAgentsReadMiddleware" in names
+    assert names.index("ToolErrorMiddleware") < names.index("SubdirAgentsReadMiddleware")
+
+
 @pytest.mark.asyncio
 async def test_agent_keeps_message_queue_and_step_limit_middleware() -> None:
     captured = await _capture_create_deep_agent_kwargs()
@@ -101,3 +111,13 @@ async def test_agent_keeps_message_queue_and_step_limit_middleware() -> None:
     present = {type(m).__name__ for m in middleware}
     assert "check_message_queue_before_model" in present
     assert "notify_step_limit_reached" in present
+
+
+@pytest.mark.asyncio
+async def test_agent_includes_report_platform_issue_tool() -> None:
+    from agent.tools import report_platform_issue
+
+    captured = await _capture_create_deep_agent_kwargs()
+    tools = captured["tools"]
+    assert isinstance(tools, list)
+    assert report_platform_issue in tools
diff --git a/tests/test_report_platform_issue_tool.py b/tests/test_report_platform_issue_tool.py
new file mode 100644
index 00000000..0422ecd3
--- /dev/null
+++ b/tests/test_report_platform_issue_tool.py
@@ -0,0 +1,20 @@
+from __future__ import annotations
+
+import uuid
+
+
+async def test_report_platform_issue_returns_uuid7_report_id() -> None:
+    from agent.tools.report_platform_issue import report_platform_issue
+
+    result = await report_platform_issue()
+
+    assert set(result) == {"report_id"}
+    report_id = uuid.UUID(result["report_id"])
+    assert report_id.version == 7
+    assert report_id.variant == uuid.RFC_4122
+
+
+def test_report_platform_issue_exported() -> None:
+    from agent.tools import report_platform_issue
+
+    assert callable(report_platform_issue)
diff --git a/tests/test_subdir_agents_middleware.py b/tests/test_subdir_agents_middleware.py
new file mode 100644
index 00000000..488e45d5
--- /dev/null
+++ b/tests/test_subdir_agents_middleware.py
@@ -0,0 +1,161 @@
+"""Tests for subdirectory AGENTS.md auto-loading on read_file."""
+
+from __future__ import annotations
+
+from types import SimpleNamespace
+from typing import Any
+
+import pytest
+from langchain_core.messages import ToolMessage
+
+from agent.middleware.subdir_agents import SubdirAgentsReadMiddleware
+from agent.utils import sandbox_state
+
+
+class FakeReadResult:
+    def __init__(
+        self, *, content: str | None = None, encoding: str = "utf-8", error: str | None = None
+    ) -> None:
+        self.error = error
+        self.file_data = None if content is None else {"content": content, "encoding": encoding}
+
+
+class FakeBackend:
+    def __init__(self, results: dict[str, Any]) -> None:
+        self.results = results
+        self.reads: list[str] = []
+
+    async def aread(self, file_path: str, offset: int = 0, limit: int = 2000) -> Any:
+        self.reads.append(file_path)
+        result = self.results.get(file_path)
+        if isinstance(result, Exception):
+            raise result
+        if result is None:
+            return FakeReadResult(error="File not found")
+        return result
+
+
+def _request(name: str, args: dict[str, Any], thread_id: str = "t1") -> Any:
+    return SimpleNamespace(
+        tool_call={"name": name, "args": args, "id": "call-1"},
+        runtime=SimpleNamespace(config={"configurable": {"thread_id": thread_id}}),
+    )
+
+
+def _ok(name: str, content: str = "file content") -> ToolMessage:
+    return ToolMessage(content=content, tool_call_id="call-1", status="success", name=name)
+
+
+@pytest.fixture
+def register_backend():
+    registered: list[str] = []
+
+    def _register(thread_id: str, backend: Any) -> Any:
+        sandbox_state.SANDBOX_BACKENDS[thread_id] = backend
+        registered.append(thread_id)
+        return backend
+
+    yield _register
+    for thread_id in registered:
+        sandbox_state.SANDBOX_BACKENDS.pop(thread_id, None)
+
+
+async def test_read_file_appends_applicable_agents_in_root_to_leaf_order(register_backend) -> None:
+    backend = FakeBackend(
+        {
+            "/repo/AGENTS.md": FakeReadResult(content="root rules"),
+            "/repo/pkg/AGENTS.md": FakeReadResult(content="pkg rules"),
+        }
+    )
+    register_backend("t1", backend)
+    request = _request("read_file", {"file_path": "/repo/pkg/src/app.py"})
+
+    async def handler(_req: Any) -> ToolMessage:
+        return _ok("read_file")
+
+    result = await SubdirAgentsReadMiddleware().awrap_tool_call(request, handler)
+
+    assert isinstance(result.content, str)
+    assert "<system-reminder>" in result.content
+    assert "Loaded applicable AGENTS.md instructions for `/repo/pkg/src/app.py`" in result.content
+    assert result.content.index("Instructions from: /repo/AGENTS.md") < result.content.index(
+        "Instructions from: /repo/pkg/AGENTS.md"
+    )
+    assert "root rules" in result.content
+    assert "pkg rules" in result.content
+    assert backend.reads == [
+        "/repo/AGENTS.md",
+        "/repo/pkg/AGENTS.md",
+        "/repo/pkg/src/AGENTS.md",
+    ]
+
+
+async def test_read_file_does_not_reload_same_agents_file(register_backend) -> None:
+    backend = FakeBackend({"/repo/pkg/AGENTS.md": FakeReadResult(content="pkg rules")})
+    register_backend("t1", backend)
+    middleware = SubdirAgentsReadMiddleware()
+
+    async def handler(_req: Any) -> ToolMessage:
+        return _ok("read_file")
+
+    first = await middleware.awrap_tool_call(
+        _request("read_file", {"file_path": "/repo/pkg/a.py"}), handler
+    )
+    second = await middleware.awrap_tool_call(
+        _request("read_file", {"file_path": "/repo/pkg/b.py"}), handler
+    )
+
+    assert isinstance(first.content, str)
+    assert "pkg rules" in first.content
+    assert isinstance(second.content, str)
+    assert "system-reminder" not in second.content
+    assert backend.reads == ["/repo/AGENTS.md", "/repo/pkg/AGENTS.md"]
+
+
+async def test_reading_agents_md_directly_does_not_append_reminder(register_backend) -> None:
+    backend = FakeBackend({"/repo/pkg/AGENTS.md": FakeReadResult(content="pkg rules")})
+    register_backend("t1", backend)
+    request = _request("read_file", {"file_path": "/repo/pkg/AGENTS.md"})
+
+    async def handler(_req: Any) -> ToolMessage:
+        return _ok("read_file", "pkg rules")
+
+    result = await SubdirAgentsReadMiddleware().awrap_tool_call(request, handler)
+
+    assert result.content == "pkg rules"
+    assert backend.reads == []
+
+
+async def test_non_read_file_tool_is_untouched(register_backend) -> None:
+    backend = FakeBackend({"/repo/AGENTS.md": FakeReadResult(content="root rules")})
+    register_backend("t1", backend)
+    request = _request("edit_file", {"file_path": "/repo/a.py"})
+
+    async def handler(_req: Any) -> ToolMessage:
+        return _ok("edit_file")
+
+    result = await SubdirAgentsReadMiddleware().awrap_tool_call(request, handler)
+
+    assert result.content == "file content"
+    assert backend.reads == []
+
+
+async def test_missing_backend_is_graceful() -> None:
+    request = _request("read_file", {"file_path": "/repo/a.py"}, thread_id="absent-thread")
+
+    async def handler(_req: Any) -> ToolMessage:
+        return _ok("read_file")
+
+    result = await SubdirAgentsReadMiddleware().awrap_tool_call(request, handler)
+
+    assert result.content == "file content"
+
+
+def test_sync_tool_call_is_not_supported() -> None:
+    request = _request("read_file", {"file_path": "/repo/a.py"})
+
+    def handler(_req: Any) -> ToolMessage:
+        return _ok("read_file")
+
+    with pytest.raises(NotImplementedError):
+        SubdirAgentsReadMiddleware().wrap_tool_call(request, handler)