fix(agents): substitute prompt placeholders in a single pass

lib/crewai/src/crewai/experimental/agent_executor.py

@@ -8,6 +8,7 @@
 from datetime import datetime
 import inspect
 import json
+import re
 import threading
 from typing import TYPE_CHECKING, Any, Literal, TypeVar, cast
 from uuid import uuid4
@@ -3149,16 +3150,22 @@ async def _ainject_files_from_inputs(self, inputs: dict[str, Any]) -> None:
     def _format_prompt(prompt: str, inputs: dict[str, str]) -> str:
         """Format prompt template with input values.
 
+        Substitutes every placeholder in a single pass so a substituted value
+        that itself contains a placeholder token (e.g. task input mentioning
+        the literal ``{tools}``) is not clobbered by a later replacement.
+
         Args:
             prompt: Template string.
             inputs: Values to substitute.
 
         Returns:
             Formatted prompt.
         """
-        prompt = prompt.replace("{input}", inputs["input"])
-        prompt = prompt.replace("{tool_names}", inputs["tool_names"])
-        return prompt.replace("{tools}", inputs["tools"])
+        return re.sub(
+            r"\{(input|tool_names|tools)\}",
+            lambda match: inputs[match.group(1)],
+            prompt,
+        )
 
     def _handle_human_feedback(self, formatted_answer: AgentFinish) -> AgentFinish:
         """Process human feedback and refine answer.

lib/crewai/tests/agents/test_agent_executor.py

@@ -475,6 +475,29 @@ def test_format_prompt(self, mock_dependencies):
         assert "tool1, tool2" in result
         assert "desc" in result
 
+    def test_format_prompt_preserves_placeholder_tokens_in_values(
+        self, mock_dependencies
+    ):
+        """A value containing a placeholder token must not be re-substituted.
+
+        Regression: sequential ``str.replace`` substituted ``{input}`` first, so
+        task input that legitimately mentioned ``{tools}`` or ``{tool_names}``
+        had those tokens clobbered by the later replacements.
+        """
+        executor = _build_executor(**mock_dependencies)
+        inputs = {
+            "input": "explain the {tools} and {tool_names} placeholders",
+            "tool_names": "search",
+            "tools": "search: web search",
+        }
+
+        result = executor._format_prompt("Task: {input}\nTools: {tools}", inputs)
+
+        assert result == (
+            "Task: explain the {tools} and {tool_names} placeholders\n"
+            "Tools: search: web search"
+        )
+
     def test_is_training_mode_false(self, mock_dependencies):
         """Test training mode detection when not in training."""
         executor = _build_executor(**mock_dependencies)