From 236e8082dc8f6f95c34781987aaf328da14c15cf Mon Sep 17 00:00:00 2001
From: evalstate <1936278+evalstate@users.noreply.github.com>
Date: Tue, 25 Nov 2025 23:34:59 +0000
Subject: [PATCH] integration test

---
 src/fast_agent/core/fastagent.py              |  9 +++++
 .../integration/instruction_templates/FOO.md  |  1 +
 .../fastagent.config.yaml                     |  7 ++++
 .../test_file_silent_instruction.py           | 38 +++++++++++++++++++
 4 files changed, 55 insertions(+)
 create mode 100644 tests/integration/instruction_templates/FOO.md
 create mode 100644 tests/integration/instruction_templates/fastagent.config.yaml
 create mode 100644 tests/integration/instruction_templates/test_file_silent_instruction.py

diff --git a/src/fast_agent/core/fastagent.py b/src/fast_agent/core/fastagent.py
index 79e3f174..b0693684 100644
--- a/src/fast_agent/core/fastagent.py
+++ b/src/fast_agent/core/fastagent.py
@@ -865,6 +865,15 @@ def _apply_instruction_context(
             if request_params is not None:
                 request_params.systemPrompt = resolved
 
+            # TODO -- find a cleaner way of doing this
+            # Keep any attached LLM in sync so the provider sees the resolved prompt
+            llm = getattr(agent, "_llm", None)
+            if llm is not None:
+                if getattr(llm, "default_request_params", None) is not None:
+                    llm.default_request_params.systemPrompt = resolved
+                if hasattr(llm, "instruction"):
+                    llm.instruction = resolved
+
     def _apply_skills_to_agent_configs(self, default_skills: list[SkillManifest]) -> None:
         self._default_skill_manifests = list(default_skills)
 
diff --git a/tests/integration/instruction_templates/FOO.md b/tests/integration/instruction_templates/FOO.md
new file mode 100644
index 00000000..5b1daa9b
--- /dev/null
+++ b/tests/integration/instruction_templates/FOO.md
@@ -0,0 +1 @@
+This text came from FOO.md and should replace the placeholder.
diff --git a/tests/integration/instruction_templates/fastagent.config.yaml b/tests/integration/instruction_templates/fastagent.config.yaml
new file mode 100644
index 00000000..6adebe3f
--- /dev/null
+++ b/tests/integration/instruction_templates/fastagent.config.yaml
@@ -0,0 +1,7 @@
+default_model: passthrough
+
+logger:
+  level: "error"
+  progress_display: false
+  show_chat: false
+  show_tools: false
diff --git a/tests/integration/instruction_templates/test_file_silent_instruction.py b/tests/integration/instruction_templates/test_file_silent_instruction.py
new file mode 100644
index 00000000..0ba63dcb
--- /dev/null
+++ b/tests/integration/instruction_templates/test_file_silent_instruction.py
@@ -0,0 +1,38 @@
+from pathlib import Path
+
+import pytest
+
+
+@pytest.mark.integration
+@pytest.mark.asyncio
+async def test_file_silent_reaches_llm_request_params(fast_agent):
+    """Ensure {{file_silent:...}} is resolved before the LLM sees the system prompt."""
+    fast = fast_agent
+    file_text = Path("FOO.md").read_text(encoding="utf-8").strip()
+
+    @fast.agent(
+        name="file_template_agent",
+        instruction="System prompt start. {{file_silent:FOO.md}}",
+        model="passthrough",
+    )
+    async def agent_function():
+        async with fast.run() as agent_app:
+            agent = agent_app.file_template_agent
+
+            # Agent-facing instruction should have the file contents applied
+            assert "{{file_silent:FOO.md}}" not in agent.instruction
+            assert file_text in agent.instruction
+
+            # The LLM request params (what the provider sees) should also be resolved
+            request_params = agent.llm.get_request_params()
+            assert request_params.systemPrompt is not None
+            assert "{{file_silent:FOO.md}}" not in request_params.systemPrompt
+            assert file_text in request_params.systemPrompt
+
+            # Default params should stay in sync for future calls
+            assert file_text in agent.llm.default_request_params.systemPrompt
+
+            response = await agent.send("ping")
+            assert "ping" in response
+
+    await agent_function()