From 5f6d3fa96bd125626bcca004f5fad2291c6ef36a Mon Sep 17 00:00:00 2001
From: Alex Fournier <afournier@nvidia.com>
Date: Wed, 2 Sep 2026 09:35:21 -0700
Subject: [PATCH] fix(translation): preserve OpenAI tool strictness for
 Anthropic

Signed-off-by: Alex Fournier <afournier@nvidia.com>
---
 .../src/codecs/anthropic/buffered.rs          |  8 +++-
 .../tests/request_translation.rs              | 38 +++++++++++++++++++
 2 files changed, 44 insertions(+), 2 deletions(-)

diff --git a/crates/switchyard-translation/src/codecs/anthropic/buffered.rs b/crates/switchyard-translation/src/codecs/anthropic/buffered.rs
index 723744021..87b907fb5 100644
--- a/crates/switchyard-translation/src/codecs/anthropic/buffered.rs
+++ b/crates/switchyard-translation/src/codecs/anthropic/buffered.rs
@@ -1044,11 +1044,15 @@ fn encode_anthropic_tools(tools: &[ToolDefinition]) -> Value {
         tools
             .iter()
             .map(|tool| {
-                json!({
+                let mut item = json!({
                     "name": tool.name,
                     "description": tool.description.clone().unwrap_or_default(),
                     "input_schema": tool.parameters,
-                })
+                });
+                if let Some(strict) = tool.strict {
+                    item["strict"] = Value::Bool(strict);
+                }
+                item
             })
             .collect(),
     )
diff --git a/crates/switchyard-translation/tests/request_translation.rs b/crates/switchyard-translation/tests/request_translation.rs
index 22b710b05..7338a8d16 100644
--- a/crates/switchyard-translation/tests/request_translation.rs
+++ b/crates/switchyard-translation/tests/request_translation.rs
@@ -1853,6 +1853,44 @@ fn openai_schema_constraints_are_removed_from_anthropic_output_format() -> TestR
     Ok(())
 }
 
+// Verifies OpenAI tool strictness survives translation to Anthropic.
+#[test]
+fn openai_tool_strictness_is_preserved_for_anthropic() -> TestResult {
+    let engine = TranslationEngine::default();
+    let body = json!({
+        "model": "gpt-5",
+        "messages": [{"role": "user", "content": "Use a tool."}],
+        "tools": [
+            {
+                "type": "function",
+                "function": {"name": "strict", "parameters": {}, "strict": true}
+            },
+            {
+                "type": "function",
+                "function": {"name": "non_strict", "parameters": {}, "strict": false}
+            },
+            {
+                "type": "function",
+                "function": {"name": "unspecified", "parameters": {}}
+            }
+        ]
+    });
+
+    let output = engine
+        .translate_request(
+            WireFormat::OpenAiChat,
+            WireFormat::AnthropicMessages,
+            &body,
+            &TranslationPolicy::default(),
+        )?
+        .body;
+
+    assert_eq!(output["tools"][0]["strict"], true);
+    assert_eq!(output["tools"][1]["strict"], false);
+    assert!(output["tools"][2].get("strict").is_none());
+    Ok(())
+}
+
 // Verifies Anthropic-bound OpenAI requests get the required max_tokens fallback.
 #[test]
 fn openai_request_to_anthropic_adds_required_default_max_tokens() -> TestResult {