Add runtime context middleware (#255)

EvoScientist/EvoScientist.py

@@ -20,7 +20,6 @@ Usage:
 import json
 import logging
 import os
-from datetime import datetime
 from pathlib import Path
 
 from langchain.agents.middleware import AgentMiddleware, HumanInTheLoopMiddleware
@@ -28,7 +27,7 @@ from langchain.agents.middleware import AgentMiddleware, HumanInTheLoopMiddlewar
 from . import paths as _paths_mod
 from .config import apply_config_to_env, get_effective_config
 from .paths import set_active_workspace, set_workspace_root
-from .prompts import RESEARCHER_INSTRUCTIONS, get_system_prompt
+from .prompts import get_system_prompt
 
 # Suppress noisy warnings from deepagents skill loader (non-string frontmatter fields, etc.)
 logging.getLogger("deepagents.middleware.skills").setLevel(logging.ERROR)
@@ -198,6 +197,7 @@ def _inject_subagent_middleware(subs: list[dict]) -> None:
         ContextOverflowMapperMiddleware,
         ToolErrorHandlerMiddleware,
         create_context_editing_middleware,
+        create_runtime_context_middleware,
     )
 
     for sa in subs:
@@ -206,21 +206,13 @@ def _inject_subagent_middleware(subs: list[dict]) -> None:
                 # No ``model=`` — subagents share the main agent's model,
                 # so defer to the factory's ``_ensure_chat_model()`` fallback.
                 create_context_editing_middleware(),
+                create_runtime_context_middleware(),
                 ToolErrorHandlerMiddleware(),
                 ContextOverflowMapperMiddleware(),
             ]
         )
 
 
-def _build_prompt_refs() -> dict:
-    """Build prompt references with the current date (not frozen at import)."""
-    return {
-        "RESEARCHER_INSTRUCTIONS": RESEARCHER_INSTRUCTIONS.format(
-            date=datetime.now().strftime("%Y-%m-%d"),
-        ),
-    }
-
-
 def _maybe_swap_async_subagents(subs: list, middleware: list | None = None) -> list:
     """Replace ``_async``-flagged sub-agents with ``AsyncSubAgent`` specs when enabled.
 
@@ -333,7 +325,6 @@ def _build_base_kwargs(base_backend, base_middleware):
     subs = load_subagents(
         SUBAGENTS_CONFIG,
         tool_registry=tool_registry,
-        prompt_refs=_build_prompt_refs(),
     )
     _inject_subagent_middleware(subs)
     subs = _maybe_swap_async_subagents(subs, base_middleware)
@@ -382,7 +373,6 @@ def load_mcp_and_build_kwargs(base_backend, base_middleware, *, on_mcp_progress=
     subs = load_subagents(
         SUBAGENTS_CONFIG,
         tool_registry=registry,
-        prompt_refs=_build_prompt_refs(),
     )
 
     _inject_subagent_middleware(subs)
@@ -476,6 +466,7 @@ def _get_default_middleware(
         create_code_interpreter_middleware,
         create_context_editing_middleware,
         create_memory_middleware,
+        create_runtime_context_middleware,
         create_tool_selector_middleware,
         load_fallback_chain,
     )
@@ -496,6 +487,7 @@ def _get_default_middleware(
         ContextOverflowMapperMiddleware(),
         ToolErrorHandlerMiddleware(),
         *create_tool_selector_middleware(model=model),
+        create_runtime_context_middleware(),
         create_memory_middleware(memory_dir, workspace_dir=workspace_dir),
     ]
 

EvoScientist/__init__.py

@@ -29,7 +29,6 @@ _EXPORTS: dict[str, tuple[str, str]] = {
     "DEFAULT_MODEL": (".llm", "DEFAULT_MODEL"),
     # Prompts
     "get_system_prompt": (".prompts", "get_system_prompt"),
-    "RESEARCHER_INSTRUCTIONS": (".prompts", "RESEARCHER_INSTRUCTIONS"),
     # Tools
     "tavily_search": (".tools", "tavily_search"),
     "think_tool": (".tools", "think_tool"),

EvoScientist/middleware/__init__.py

@@ -23,6 +23,7 @@ from .memory import (
     create_memory_middleware,
 )
 from .model_fallback import ModelFallbackMiddleware, load_fallback_chain
+from .runtime_context import RuntimeContextMiddleware, create_runtime_context_middleware
 from .tool_error_handler import ToolErrorHandlerMiddleware
 from .tool_selector import create_tool_selector_middleware
 from .utils import disable_thinking
@@ -37,11 +38,13 @@ __all__ = [
     "EvoMemoryMiddleware",
     "ModelFallbackMiddleware",
     "Question",
+    "RuntimeContextMiddleware",
     "ToolErrorHandlerMiddleware",
     "compute_context_editing_trigger",
     "create_code_interpreter_middleware",
     "create_context_editing_middleware",
     "create_memory_middleware",
+    "create_runtime_context_middleware",
     "create_tool_selector_middleware",
     "disable_thinking",
     "load_fallback_chain",

EvoScientist/middleware/runtime_context.py

@@ -0,0 +1,86 @@
+"""Runtime context middleware for EvoScientist."""
+
+from __future__ import annotations
+
+from collections.abc import Awaitable, Callable
+from datetime import datetime
+
+from langchain.agents.middleware.types import (
+    AgentMiddleware,
+    ModelRequest,
+    ModelResponse,
+)
+
+RUNTIME_CONTEXT_TEMPLATE = """<runtime_context>
+Current date: {date}
+Local timezone: {timezone}
+
+Use this context to resolve relative time references like today, yesterday, and
+next week.
+</runtime_context>"""
+
+
+def _format_timezone(now: datetime) -> str:
+    """Return a compact local timezone label for prompt injection."""
+    offset = now.utcoffset()
+    if offset is None:
+        return "local"
+
+    total_seconds = int(offset.total_seconds())
+    sign = "+" if total_seconds >= 0 else "-"
+    total_seconds = abs(total_seconds)
+    hours, remainder = divmod(total_seconds, 3600)
+    minutes = remainder // 60
+    offset_text = f"UTC{sign}{hours:02d}:{minutes:02d}"
+
+    name = now.tzname()
+    if name and name != offset_text:
+        return f"{name} ({offset_text})"
+    return offset_text
+
+
+class RuntimeContextMiddleware(AgentMiddleware):
+    """Inject per-turn runtime context into model calls."""
+
+    def __init__(self, *, now_fn: Callable[[], datetime] | None = None) -> None:
+        self._now_fn = now_fn or (lambda: datetime.now().astimezone())
+
+    def _runtime_context(self) -> str:
+        now = self._now_fn()
+        return RUNTIME_CONTEXT_TEMPLATE.format(
+            date=now.strftime("%Y-%m-%d"),
+            timezone=_format_timezone(now),
+        )
+
+    def modify_request(self, request: ModelRequest) -> ModelRequest:
+        """Append runtime context to the system prompt."""
+        from deepagents.middleware._utils import append_to_system_message
+
+        new_system = append_to_system_message(
+            request.system_message,
+            self._runtime_context(),
+        )
+        return request.override(system_message=new_system)
+
+    def wrap_model_call(
+        self,
+        request: ModelRequest,
+        handler: Callable[[ModelRequest], ModelResponse],
+    ) -> ModelResponse:
+        """Inject runtime context before the sync model handler."""
+        return handler(self.modify_request(request))
+
+    async def awrap_model_call(
+        self,
+        request: ModelRequest,
+        handler: Callable[[ModelRequest], Awaitable[ModelResponse]],
+    ) -> ModelResponse:
+        """Inject runtime context before the async model handler."""
+        return await handler(self.modify_request(request))
+
+
+def create_runtime_context_middleware(
+    *, now_fn: Callable[[], datetime] | None = None
+) -> RuntimeContextMiddleware:
+    """Build runtime-context middleware."""
+    return RuntimeContextMiddleware(now_fn=now_fn)

EvoScientist/prompts.py

@@ -13,8 +13,7 @@ The main agent's system prompt is assembled by :func:`get_system_prompt` from:
 - :data:`ASYNC_NOTIFICATIONS` — how to triage `[Async tasks update]` signals
   from async sub-agents
 
-:data:`RESEARCHER_INSTRUCTIONS` is the research-agent sub-agent prompt,
-loaded via ``_build_prompt_refs`` in ``EvoScientist.py``.
+Built-in sub-agent prompts live in ``EvoScientist/subagents/*.yaml``.
 
 Style notes
 -----------
@@ -346,56 +345,6 @@ For EACH task in the batch, independently:
 It is fine to fetch one task and defer another from the same batch.
 """
 
-# =============================================================================
-# Sub-agent research instructions
-# =============================================================================
-
-RESEARCHER_INSTRUCTIONS = """You are a research assistant. Today's date is {date}.
-
-## Task
-Use tools to gather information on the assigned topic (methods, baselines, datasets, or prior results) to support experimental planning or iteration. Prefer actionable details: datasets, metrics, code availability, and common pitfalls. Do not fabricate citations or URLs. Capture evaluation protocols (splits, metrics, calibration) and known failure modes.
-
-## Available Tools
-- `think_tool` — Reflect on findings and plan next steps
-- `read_file` — Read skill instructions when a skill matches the task (paths shown in your available skills listing)
-- Optionally, some web search tools to find information online.
-
-**CRITICAL:** Use `think_tool` after each search
-
-## Research Strategy
-1. Read the question carefully
-2. Start with broad searches
-3. After each search, reflect: Do I have enough? What's missing?
-4. Narrow searches to fill gaps
-5. Stop when you can answer confidently
-
-## Hard Limits
-- Simple queries: 2-3 searches maximum
-- Complex queries: up to 5 searches maximum
-- Stop after 5 searches regardless
-
-## Stop When
-- You can answer comprehensively
-- You have 3+ relevant sources
-- Last 2 searches returned similar information
-
-## Response Format
-Structure findings with clear headings and cite sources inline:
-
-```
-## Key Findings
-
-Finding one with context [1]. Another insight [2].
-
-## Recommended Next Experiments
-- One actionable experiment suggestion with motivation and expected outcome.
-
-### Sources
-[1] Title: URL
-[2] Title: URL
-```
-"""
-
 # =============================================================================
 # Combined exports
 # =============================================================================
@@ -414,10 +363,10 @@ def get_system_prompt() -> str:
     6. :data:`DELEGATION_STRATEGY`
     7. :data:`ASYNC_NOTIFICATIONS`
 
-    The current date is injected per-turn by
-    :class:`EvoScientist.middleware.EvoMemoryMiddleware` (piggy-backing on its
-    existing ``<evo_memory>`` injection), so the static prefix here remains
-    byte-stable across midnight rollover and across long-running daemons.
+    Runtime context is injected per-turn by
+    :class:`EvoScientist.middleware.RuntimeContextMiddleware`, so the static
+    prefix here remains byte-stable across midnight rollover and across
+    long-running daemons.
 
     Returns:
         Combined static system prompt string.

EvoScientist/subagents/_factory.py

@@ -40,7 +40,6 @@ def build_async_subagent_graph(name: str) -> Any:
     from EvoScientist.config import apply_config_to_env, get_effective_config
     from EvoScientist.EvoScientist import (
         SUBAGENTS_CONFIG,
-        _build_prompt_refs,
         _ensure_chat_model,
         _get_default_backend,
         _get_default_middleware,
@@ -63,7 +62,6 @@ def build_async_subagent_graph(name: str) -> Any:
     specs = load_subagents(
         SUBAGENTS_CONFIG,
         tool_registry=tool_registry,
-        prompt_refs=_build_prompt_refs(),
     )
     spec = next((s for s in specs if s.get("name") == name), None)
     if spec is None:

EvoScientist/subagents/research.yaml

@@ -2,4 +2,48 @@ research-agent:
   description: "Web research for methods/baselines/datasets (one topic at a time, return actionable notes + sources)."
   tools: [tavily_search, think_tool]
   skills: ["/skills/"]
-  system_prompt_ref: RESEARCHER_INSTRUCTIONS
+  system_prompt: |
+    You are a research assistant.
+
+    ## Task
+    Use tools to gather information on the assigned topic (methods, baselines, datasets, or prior results) to support experimental planning or iteration. Prefer actionable details: datasets, metrics, code availability, and common pitfalls. Do not fabricate citations or URLs. Capture evaluation protocols (splits, metrics, calibration) and known failure modes.
+
+    ## Available Tools
+    - `think_tool` - Reflect on findings and plan next steps
+    - `read_file` - Read skill instructions when a skill matches the task (paths shown in your available skills listing)
+    - Optionally, some web search tools to find information online.
+
+    **CRITICAL:** Use `think_tool` after each search
+
+    ## Research Strategy
+    1. Read the question carefully
+    2. Start with broad searches
+    3. After each search, reflect: Do I have enough? What's missing?
+    4. Narrow searches to fill gaps
+    5. Stop when you can answer confidently
+
+    ## Hard Limits
+    - Simple queries: 2-3 searches maximum
+    - Complex queries: up to 5 searches maximum
+    - Stop after 5 searches regardless
+
+    ## Stop When
+    - You can answer comprehensively
+    - You have 3+ relevant sources
+    - Last 2 searches returned similar information
+
+    ## Response Format
+    Structure findings with clear headings and cite sources inline:
+
+    ```
+    ## Key Findings
+
+    Finding one with context [1]. Another insight [2].
+
+    ## Recommended Next Experiments
+    - One actionable experiment suggestion with motivation and expected outcome.
+
+    ### Sources
+    [1] Title: URL
+    [2] Title: URL
+    ```

EvoScientist/utils.py

@@ -137,7 +137,8 @@ def load_subagents(
         research-agent:
           description: "..."
           tools: [tavily_search, think_tool]
-          system_prompt_ref: RESEARCHER_INSTRUCTIONS
+          system_prompt: |
+            ...
     """
     prompt_refs = prompt_refs or {}
 

tests/test_async_subagent_factory.py

@@ -17,7 +17,6 @@ from unittest.mock import MagicMock, patch
 @patch("EvoScientist.EvoScientist._get_default_middleware", return_value=[])
 @patch("EvoScientist.EvoScientist._get_default_backend")
 @patch("EvoScientist.EvoScientist._ensure_chat_model")
-@patch("EvoScientist.EvoScientist._build_prompt_refs", return_value={})
 @patch("EvoScientist.utils.load_subagents")
 @patch("EvoScientist.config.apply_config_to_env")
 @patch("EvoScientist.config.get_effective_config")
@@ -25,7 +24,6 @@ def test_factory_requests_async_safe_middleware(
     mock_get_cfg,
     mock_apply_env,
     mock_load_subs,
-    mock_prompt_refs,
     mock_chat,
     mock_backend,
     mock_get_mw,

tests/test_prompts.py

@@ -63,16 +63,15 @@ class TestGetSystemPrompt:
         assert 0 <= idx_identity < idx_workflow < idx_delegation
 
     def test_does_not_contain_static_date(self):
-        """Date is injected per-turn by EvoMemoryMiddleware, not baked into static prompt.
+        """Date is injected per-turn by runtime context, not baked into static prompt.
 
         Static prompt must stay byte-stable across midnight so the cache prefix
-        survives. See EvoMemoryMiddleware.modify_request for runtime injection.
+        survives. See RuntimeContextMiddleware for runtime injection.
         """
         import re
 
         result = get_system_prompt()
-        # No literal "Today's date is YYYY-MM-DD." in the static prompt.
-        assert not re.search(r"Today's date is \d{4}-\d{2}-\d{2}", result)
+        assert not re.search(r"Current date: \d{4}-\d{2}-\d{2}", result)
 
     def test_mentions_skill_manager_for_discovery(self):
         """Agent must know it can browse/install skills from the EvoSkills catalog."""

tests/test_runtime_context_middleware.py

@@ -0,0 +1,113 @@
+from __future__ import annotations
+
+from datetime import UTC, datetime
+from types import SimpleNamespace
+from unittest.mock import MagicMock, patch
+
+from langchain_core.messages import SystemMessage
+
+from EvoScientist.middleware.runtime_context import (
+    RuntimeContextMiddleware,
+    create_runtime_context_middleware,
+)
+
+
+def _request():
+    request = SimpleNamespace(
+        state={},
+        runtime=object(),
+        system_message=SystemMessage(content="base system"),
+    )
+    request.override = lambda **kwargs: SimpleNamespace(
+        **{
+            "state": request.state,
+            "runtime": request.runtime,
+            "system_message": kwargs.get("system_message", request.system_message),
+        }
+    )
+    return request
+
+
+def _system_text(modified) -> str:
+    system_message = modified.system_message
+    assert system_message is not None
+    return str(system_message.content)
+
+
+def _mock_config():
+    cfg = MagicMock()
+    cfg.enable_ask_user = False
+    cfg.auto_mode = False
+    cfg.auto_approve = False
+    cfg.model_fallbacks = None
+    cfg.code_interpreter_timeout = 60
+    cfg.code_interpreter_max_result_chars = 6000
+    return cfg
+
+
+def test_runtime_context_injects_current_date_and_timezone():
+    middleware = RuntimeContextMiddleware(
+        now_fn=lambda: datetime(2026, 6, 2, 12, 0, tzinfo=UTC)
+    )
+
+    modified = middleware.modify_request(_request())
+    system_text = _system_text(modified)
+
+    assert "<runtime_context>" in system_text
+    assert "Current date: 2026-06-02" in system_text
+    assert "Local timezone: UTC (UTC+00:00)" in system_text
+    assert "today" in system_text
+
+
+@patch(
+    "EvoScientist.middleware.create_tool_selector_middleware",
+    return_value=[MagicMock(), MagicMock()],
+)
+@patch("EvoScientist.EvoScientist._ensure_chat_model")
+@patch("EvoScientist.EvoScientist._ensure_config")
+def test_default_middleware_includes_runtime_context(
+    mock_config, mock_model, mock_tool_selector
+):
+    mock_config.return_value = _mock_config()
+    mock_model.return_value = MagicMock(profile={"max_input_tokens": 200_000})
+
+    from EvoScientist.EvoScientist import _get_default_middleware
+
+    middleware = _get_default_middleware()
+
+    assert any(isinstance(m, RuntimeContextMiddleware) for m in middleware)
+
+
+@patch(
+    "EvoScientist.middleware.create_tool_selector_middleware",
+    return_value=[MagicMock(), MagicMock()],
+)
+@patch("EvoScientist.EvoScientist._ensure_chat_model")
+@patch("EvoScientist.EvoScientist._ensure_config")
+def test_async_subagent_middleware_includes_runtime_context(
+    mock_config, mock_model, mock_tool_selector
+):
+    mock_config.return_value = _mock_config()
+    mock_model.return_value = MagicMock(profile={"max_input_tokens": 200_000})
+
+    from EvoScientist.EvoScientist import _get_default_middleware
+
+    middleware = _get_default_middleware(for_async_subagent=True)
+
+    assert any(isinstance(m, RuntimeContextMiddleware) for m in middleware)
+
+
+@patch("EvoScientist.EvoScientist._ensure_chat_model")
+def test_configured_subagent_middleware_includes_runtime_context(mock_model):
+    mock_model.return_value = MagicMock(profile={"max_input_tokens": 200_000})
+
+    from EvoScientist.EvoScientist import _inject_subagent_middleware
+
+    subs = [{"name": "test-agent"}]
+    _inject_subagent_middleware(subs)
+
+    assert any(isinstance(m, RuntimeContextMiddleware) for m in subs[0]["middleware"])
+
+
+def test_runtime_context_factory_returns_middleware():
+    assert isinstance(create_runtime_context_middleware(), RuntimeContextMiddleware)