diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5c93dd1554..acfdbfb1a7 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,6 +8,7 @@
 
 ### 🔧 Bug Fixes & Refactors
 
+- **fix(translator):** treat `developer` role as system in OpenAI → Claude translation — `openAIToClaude` now extracts `developer`-role messages into `systemParts` (same as `system`) and filters them from the non-system message list, preventing identity context injected via the Responses API `developer` role from silently becoming an assistant turn when routing to a Claude-format provider. ([#2407](https://github.com/diegosouzapw/OmniRoute/issues/2407))
 - **fix(antigravity):** deduplicate `removeHeaderCaseInsensitive` — export canonical implementation from `antigravityClientProfile.ts` and remove the local copy in `antigravity.ts`; export `AntigravityCredentialsLike` type for cross-module use. (#2433 — thanks @Gi99lin)
 
 ### 🔒 Security Fixes
diff --git a/docs/i18n/ar/CHANGELOG.md b/docs/i18n/ar/CHANGELOG.md
index b7c21c9d11..c7eb743fba 100644
--- a/docs/i18n/ar/CHANGELOG.md
+++ b/docs/i18n/ar/CHANGELOG.md
@@ -10,6 +10,7 @@
 
 ### 🔧 Bug Fixes & Refactors
 
+- **fix(translator):** treat `developer` role as system in OpenAI → Claude translation — `openAIToClaude` now extracts `developer`-role messages into `systemParts` (same as `system`) and filters them from the non-system message list, preventing identity context injected via the Responses API `developer` role from silently becoming an assistant turn when routing to a Claude-format provider. ([#2407](https://github.com/diegosouzapw/OmniRoute/issues/2407))
 - **fix(antigravity):** deduplicate `removeHeaderCaseInsensitive` — export canonical implementation from `antigravityClientProfile.ts` and remove the local copy in `antigravity.ts`; export `AntigravityCredentialsLike` type for cross-module use. (#2433 — thanks @Gi99lin)
 
 ### 🔒 Security Fixes
diff --git a/docs/i18n/az/CHANGELOG.md b/docs/i18n/az/CHANGELOG.md
index bc45a6ecf8..2e22b4d40f 100644
--- a/docs/i18n/az/CHANGELOG.md
+++ b/docs/i18n/az/CHANGELOG.md
@@ -10,6 +10,7 @@
 
 ### 🔧 Bug Fixes & Refactors
 
+- **fix(translator):** treat `developer` role as system in OpenAI → Claude translation — `openAIToClaude` now extracts `developer`-role messages into `systemParts` (same as `system`) and filters them from the non-system message list, preventing identity context injected via the Responses API `developer` role from silently becoming an assistant turn when routing to a Claude-format provider. ([#2407](https://github.com/diegosouzapw/OmniRoute/issues/2407))
 - **fix(antigravity):** deduplicate `removeHeaderCaseInsensitive` — export canonical implementation from `antigravityClientProfile.ts` and remove the local copy in `antigravity.ts`; export `AntigravityCredentialsLike` type for cross-module use. (#2433 — thanks @Gi99lin)
 
 ### 🔒 Security Fixes
diff --git a/docs/i18n/bg/CHANGELOG.md b/docs/i18n/bg/CHANGELOG.md
index 0ec2bc8ae3..b81806c374 100644
--- a/docs/i18n/bg/CHANGELOG.md
+++ b/docs/i18n/bg/CHANGELOG.md
@@ -10,6 +10,7 @@
 
 ### 🔧 Bug Fixes & Refactors
 
+- **fix(translator):** treat `developer` role as system in OpenAI → Claude translation — `openAIToClaude` now extracts `developer`-role messages into `systemParts` (same as `system`) and filters them from the non-system message list, preventing identity context injected via the Responses API `developer` role from silently becoming an assistant turn when routing to a Claude-format provider. ([#2407](https://github.com/diegosouzapw/OmniRoute/issues/2407))
 - **fix(antigravity):** deduplicate `removeHeaderCaseInsensitive` — export canonical implementation from `antigravityClientProfile.ts` and remove the local copy in `antigravity.ts`; export `AntigravityCredentialsLike` type for cross-module use. (#2433 — thanks @Gi99lin)
 
 ### 🔒 Security Fixes
diff --git a/docs/i18n/bn/CHANGELOG.md b/docs/i18n/bn/CHANGELOG.md
index 33f397f68f..e7250e504d 100644
--- a/docs/i18n/bn/CHANGELOG.md
+++ b/docs/i18n/bn/CHANGELOG.md
@@ -10,6 +10,7 @@
 
 ### 🔧 Bug Fixes & Refactors
 
+- **fix(translator):** treat `developer` role as system in OpenAI → Claude translation — `openAIToClaude` now extracts `developer`-role messages into `systemParts` (same as `system`) and filters them from the non-system message list, preventing identity context injected via the Responses API `developer` role from silently becoming an assistant turn when routing to a Claude-format provider. ([#2407](https://github.com/diegosouzapw/OmniRoute/issues/2407))
 - **fix(antigravity):** deduplicate `removeHeaderCaseInsensitive` — export canonical implementation from `antigravityClientProfile.ts` and remove the local copy in `antigravity.ts`; export `AntigravityCredentialsLike` type for cross-module use. (#2433 — thanks @Gi99lin)
 
 ### 🔒 Security Fixes
diff --git a/docs/i18n/cs/CHANGELOG.md b/docs/i18n/cs/CHANGELOG.md
index 1e7bc07aea..5f0d6690e1 100644
--- a/docs/i18n/cs/CHANGELOG.md
+++ b/docs/i18n/cs/CHANGELOG.md
@@ -10,6 +10,7 @@
 
 ### 🔧 Bug Fixes & Refactors
 
+- **fix(translator):** treat `developer` role as system in OpenAI → Claude translation — `openAIToClaude` now extracts `developer`-role messages into `systemParts` (same as `system`) and filters them from the non-system message list, preventing identity context injected via the Responses API `developer` role from silently becoming an assistant turn when routing to a Claude-format provider. ([#2407](https://github.com/diegosouzapw/OmniRoute/issues/2407))
 - **fix(antigravity):** deduplicate `removeHeaderCaseInsensitive` — export canonical implementation from `antigravityClientProfile.ts` and remove the local copy in `antigravity.ts`; export `AntigravityCredentialsLike` type for cross-module use. (#2433 — thanks @Gi99lin)
 
 ### 🔒 Security Fixes
diff --git a/docs/i18n/da/CHANGELOG.md b/docs/i18n/da/CHANGELOG.md
index 7f22d71a0f..2e470cb4c5 100644
--- a/docs/i18n/da/CHANGELOG.md
+++ b/docs/i18n/da/CHANGELOG.md
@@ -10,6 +10,7 @@
 
 ### 🔧 Bug Fixes & Refactors
 
+- **fix(translator):** treat `developer` role as system in OpenAI → Claude translation — `openAIToClaude` now extracts `developer`-role messages into `systemParts` (same as `system`) and filters them from the non-system message list, preventing identity context injected via the Responses API `developer` role from silently becoming an assistant turn when routing to a Claude-format provider. ([#2407](https://github.com/diegosouzapw/OmniRoute/issues/2407))
 - **fix(antigravity):** deduplicate `removeHeaderCaseInsensitive` — export canonical implementation from `antigravityClientProfile.ts` and remove the local copy in `antigravity.ts`; export `AntigravityCredentialsLike` type for cross-module use. (#2433 — thanks @Gi99lin)
 
 ### 🔒 Security Fixes
diff --git a/docs/i18n/de/CHANGELOG.md b/docs/i18n/de/CHANGELOG.md
index 2ab37987a1..042d1a334d 100644
--- a/docs/i18n/de/CHANGELOG.md
+++ b/docs/i18n/de/CHANGELOG.md
@@ -10,6 +10,7 @@
 
 ### 🔧 Bug Fixes & Refactors
 
+- **fix(translator):** treat `developer` role as system in OpenAI → Claude translation — `openAIToClaude` now extracts `developer`-role messages into `systemParts` (same as `system`) and filters them from the non-system message list, preventing identity context injected via the Responses API `developer` role from silently becoming an assistant turn when routing to a Claude-format provider. ([#2407](https://github.com/diegosouzapw/OmniRoute/issues/2407))
 - **fix(antigravity):** deduplicate `removeHeaderCaseInsensitive` — export canonical implementation from `antigravityClientProfile.ts` and remove the local copy in `antigravity.ts`; export `AntigravityCredentialsLike` type for cross-module use. (#2433 — thanks @Gi99lin)
 
 ### 🔒 Security Fixes
diff --git a/docs/i18n/es/CHANGELOG.md b/docs/i18n/es/CHANGELOG.md
index e7bed0f738..920fa6e17a 100644
--- a/docs/i18n/es/CHANGELOG.md
+++ b/docs/i18n/es/CHANGELOG.md
@@ -10,6 +10,7 @@
 
 ### 🔧 Bug Fixes & Refactors
 
+- **fix(translator):** treat `developer` role as system in OpenAI → Claude translation — `openAIToClaude` now extracts `developer`-role messages into `systemParts` (same as `system`) and filters them from the non-system message list, preventing identity context injected via the Responses API `developer` role from silently becoming an assistant turn when routing to a Claude-format provider. ([#2407](https://github.com/diegosouzapw/OmniRoute/issues/2407))
 - **fix(antigravity):** deduplicate `removeHeaderCaseInsensitive` — export canonical implementation from `antigravityClientProfile.ts` and remove the local copy in `antigravity.ts`; export `AntigravityCredentialsLike` type for cross-module use. (#2433 — thanks @Gi99lin)
 
 ### 🔒 Security Fixes
diff --git a/docs/i18n/fa/CHANGELOG.md b/docs/i18n/fa/CHANGELOG.md
index 77b2df660a..f0f388a659 100644
--- a/docs/i18n/fa/CHANGELOG.md
+++ b/docs/i18n/fa/CHANGELOG.md
@@ -10,6 +10,7 @@
 
 ### 🔧 Bug Fixes & Refactors
 
+- **fix(translator):** treat `developer` role as system in OpenAI → Claude translation — `openAIToClaude` now extracts `developer`-role messages into `systemParts` (same as `system`) and filters them from the non-system message list, preventing identity context injected via the Responses API `developer` role from silently becoming an assistant turn when routing to a Claude-format provider. ([#2407](https://github.com/diegosouzapw/OmniRoute/issues/2407))
 - **fix(antigravity):** deduplicate `removeHeaderCaseInsensitive` — export canonical implementation from `antigravityClientProfile.ts` and remove the local copy in `antigravity.ts`; export `AntigravityCredentialsLike` type for cross-module use. (#2433 — thanks @Gi99lin)
 
 ### 🔒 Security Fixes
diff --git a/docs/i18n/fi/CHANGELOG.md b/docs/i18n/fi/CHANGELOG.md
index b20de2fa87..a7a8b99203 100644
--- a/docs/i18n/fi/CHANGELOG.md
+++ b/docs/i18n/fi/CHANGELOG.md
@@ -10,6 +10,7 @@
 
 ### 🔧 Bug Fixes & Refactors
 
+- **fix(translator):** treat `developer` role as system in OpenAI → Claude translation — `openAIToClaude` now extracts `developer`-role messages into `systemParts` (same as `system`) and filters them from the non-system message list, preventing identity context injected via the Responses API `developer` role from silently becoming an assistant turn when routing to a Claude-format provider. ([#2407](https://github.com/diegosouzapw/OmniRoute/issues/2407))
 - **fix(antigravity):** deduplicate `removeHeaderCaseInsensitive` — export canonical implementation from `antigravityClientProfile.ts` and remove the local copy in `antigravity.ts`; export `AntigravityCredentialsLike` type for cross-module use. (#2433 — thanks @Gi99lin)
 
 ### 🔒 Security Fixes
diff --git a/docs/i18n/fr/CHANGELOG.md b/docs/i18n/fr/CHANGELOG.md
index b49c1dc223..d7a4748a3b 100644
--- a/docs/i18n/fr/CHANGELOG.md
+++ b/docs/i18n/fr/CHANGELOG.md
@@ -10,6 +10,7 @@
 
 ### 🔧 Bug Fixes & Refactors
 
+- **fix(translator):** treat `developer` role as system in OpenAI → Claude translation — `openAIToClaude` now extracts `developer`-role messages into `systemParts` (same as `system`) and filters them from the non-system message list, preventing identity context injected via the Responses API `developer` role from silently becoming an assistant turn when routing to a Claude-format provider. ([#2407](https://github.com/diegosouzapw/OmniRoute/issues/2407))
 - **fix(antigravity):** deduplicate `removeHeaderCaseInsensitive` — export canonical implementation from `antigravityClientProfile.ts` and remove the local copy in `antigravity.ts`; export `AntigravityCredentialsLike` type for cross-module use. (#2433 — thanks @Gi99lin)
 
 ### 🔒 Security Fixes
diff --git a/docs/i18n/gu/CHANGELOG.md b/docs/i18n/gu/CHANGELOG.md
index 64d476f914..b1e3480184 100644
--- a/docs/i18n/gu/CHANGELOG.md
+++ b/docs/i18n/gu/CHANGELOG.md
@@ -10,6 +10,7 @@
 
 ### 🔧 Bug Fixes & Refactors
 
+- **fix(translator):** treat `developer` role as system in OpenAI → Claude translation — `openAIToClaude` now extracts `developer`-role messages into `systemParts` (same as `system`) and filters them from the non-system message list, preventing identity context injected via the Responses API `developer` role from silently becoming an assistant turn when routing to a Claude-format provider. ([#2407](https://github.com/diegosouzapw/OmniRoute/issues/2407))
 - **fix(antigravity):** deduplicate `removeHeaderCaseInsensitive` — export canonical implementation from `antigravityClientProfile.ts` and remove the local copy in `antigravity.ts`; export `AntigravityCredentialsLike` type for cross-module use. (#2433 — thanks @Gi99lin)
 
 ### 🔒 Security Fixes
diff --git a/docs/i18n/he/CHANGELOG.md b/docs/i18n/he/CHANGELOG.md
index ede93f89e0..9a81272daf 100644
--- a/docs/i18n/he/CHANGELOG.md
+++ b/docs/i18n/he/CHANGELOG.md
@@ -10,6 +10,7 @@
 
 ### 🔧 Bug Fixes & Refactors
 
+- **fix(translator):** treat `developer` role as system in OpenAI → Claude translation — `openAIToClaude` now extracts `developer`-role messages into `systemParts` (same as `system`) and filters them from the non-system message list, preventing identity context injected via the Responses API `developer` role from silently becoming an assistant turn when routing to a Claude-format provider. ([#2407](https://github.com/diegosouzapw/OmniRoute/issues/2407))
 - **fix(antigravity):** deduplicate `removeHeaderCaseInsensitive` — export canonical implementation from `antigravityClientProfile.ts` and remove the local copy in `antigravity.ts`; export `AntigravityCredentialsLike` type for cross-module use. (#2433 — thanks @Gi99lin)
 
 ### 🔒 Security Fixes
diff --git a/docs/i18n/hi/CHANGELOG.md b/docs/i18n/hi/CHANGELOG.md
index 7ce3a5f9fb..64e0e3d3c8 100644
--- a/docs/i18n/hi/CHANGELOG.md
+++ b/docs/i18n/hi/CHANGELOG.md
@@ -10,6 +10,7 @@
 
 ### 🔧 Bug Fixes & Refactors
 
+- **fix(translator):** treat `developer` role as system in OpenAI → Claude translation — `openAIToClaude` now extracts `developer`-role messages into `systemParts` (same as `system`) and filters them from the non-system message list, preventing identity context injected via the Responses API `developer` role from silently becoming an assistant turn when routing to a Claude-format provider. ([#2407](https://github.com/diegosouzapw/OmniRoute/issues/2407))
 - **fix(antigravity):** deduplicate `removeHeaderCaseInsensitive` — export canonical implementation from `antigravityClientProfile.ts` and remove the local copy in `antigravity.ts`; export `AntigravityCredentialsLike` type for cross-module use. (#2433 — thanks @Gi99lin)
 
 ### 🔒 Security Fixes
diff --git a/docs/i18n/hu/CHANGELOG.md b/docs/i18n/hu/CHANGELOG.md
index 46e8f533dd..989c131268 100644
--- a/docs/i18n/hu/CHANGELOG.md
+++ b/docs/i18n/hu/CHANGELOG.md
@@ -10,6 +10,7 @@
 
 ### 🔧 Bug Fixes & Refactors
 
+- **fix(translator):** treat `developer` role as system in OpenAI → Claude translation — `openAIToClaude` now extracts `developer`-role messages into `systemParts` (same as `system`) and filters them from the non-system message list, preventing identity context injected via the Responses API `developer` role from silently becoming an assistant turn when routing to a Claude-format provider. ([#2407](https://github.com/diegosouzapw/OmniRoute/issues/2407))
 - **fix(antigravity):** deduplicate `removeHeaderCaseInsensitive` — export canonical implementation from `antigravityClientProfile.ts` and remove the local copy in `antigravity.ts`; export `AntigravityCredentialsLike` type for cross-module use. (#2433 — thanks @Gi99lin)
 
 ### 🔒 Security Fixes
diff --git a/docs/i18n/id/CHANGELOG.md b/docs/i18n/id/CHANGELOG.md
index 542f97ef76..6e066b3023 100644
--- a/docs/i18n/id/CHANGELOG.md
+++ b/docs/i18n/id/CHANGELOG.md
@@ -10,6 +10,7 @@
 
 ### 🔧 Bug Fixes & Refactors
 
+- **fix(translator):** treat `developer` role as system in OpenAI → Claude translation — `openAIToClaude` now extracts `developer`-role messages into `systemParts` (same as `system`) and filters them from the non-system message list, preventing identity context injected via the Responses API `developer` role from silently becoming an assistant turn when routing to a Claude-format provider. ([#2407](https://github.com/diegosouzapw/OmniRoute/issues/2407))
 - **fix(antigravity):** deduplicate `removeHeaderCaseInsensitive` — export canonical implementation from `antigravityClientProfile.ts` and remove the local copy in `antigravity.ts`; export `AntigravityCredentialsLike` type for cross-module use. (#2433 — thanks @Gi99lin)
 
 ### 🔒 Security Fixes
diff --git a/docs/i18n/in/CHANGELOG.md b/docs/i18n/in/CHANGELOG.md
index 01bff32dd2..cdff8561e4 100644
--- a/docs/i18n/in/CHANGELOG.md
+++ b/docs/i18n/in/CHANGELOG.md
@@ -10,6 +10,7 @@
 
 ### 🔧 Bug Fixes & Refactors
 
+- **fix(translator):** treat `developer` role as system in OpenAI → Claude translation — `openAIToClaude` now extracts `developer`-role messages into `systemParts` (same as `system`) and filters them from the non-system message list, preventing identity context injected via the Responses API `developer` role from silently becoming an assistant turn when routing to a Claude-format provider. ([#2407](https://github.com/diegosouzapw/OmniRoute/issues/2407))
 - **fix(antigravity):** deduplicate `removeHeaderCaseInsensitive` — export canonical implementation from `antigravityClientProfile.ts` and remove the local copy in `antigravity.ts`; export `AntigravityCredentialsLike` type for cross-module use. (#2433 — thanks @Gi99lin)
 
 ### 🔒 Security Fixes
diff --git a/docs/i18n/it/CHANGELOG.md b/docs/i18n/it/CHANGELOG.md
index 3ad29f7452..70900b5a07 100644
--- a/docs/i18n/it/CHANGELOG.md
+++ b/docs/i18n/it/CHANGELOG.md
@@ -10,6 +10,7 @@
 
 ### 🔧 Bug Fixes & Refactors
 
+- **fix(translator):** treat `developer` role as system in OpenAI → Claude translation — `openAIToClaude` now extracts `developer`-role messages into `systemParts` (same as `system`) and filters them from the non-system message list, preventing identity context injected via the Responses API `developer` role from silently becoming an assistant turn when routing to a Claude-format provider. ([#2407](https://github.com/diegosouzapw/OmniRoute/issues/2407))
 - **fix(antigravity):** deduplicate `removeHeaderCaseInsensitive` — export canonical implementation from `antigravityClientProfile.ts` and remove the local copy in `antigravity.ts`; export `AntigravityCredentialsLike` type for cross-module use. (#2433 — thanks @Gi99lin)
 
 ### 🔒 Security Fixes
diff --git a/docs/i18n/ja/CHANGELOG.md b/docs/i18n/ja/CHANGELOG.md
index 56d68ab955..ebf906a992 100644
--- a/docs/i18n/ja/CHANGELOG.md
+++ b/docs/i18n/ja/CHANGELOG.md
@@ -10,6 +10,7 @@
 
 ### 🔧 Bug Fixes & Refactors
 
+- **fix(translator):** treat `developer` role as system in OpenAI → Claude translation — `openAIToClaude` now extracts `developer`-role messages into `systemParts` (same as `system`) and filters them from the non-system message list, preventing identity context injected via the Responses API `developer` role from silently becoming an assistant turn when routing to a Claude-format provider. ([#2407](https://github.com/diegosouzapw/OmniRoute/issues/2407))
 - **fix(antigravity):** deduplicate `removeHeaderCaseInsensitive` — export canonical implementation from `antigravityClientProfile.ts` and remove the local copy in `antigravity.ts`; export `AntigravityCredentialsLike` type for cross-module use. (#2433 — thanks @Gi99lin)
 
 ### 🔒 Security Fixes
diff --git a/docs/i18n/ko/CHANGELOG.md b/docs/i18n/ko/CHANGELOG.md
index 6bfa6f2f82..18e64bd9e2 100644
--- a/docs/i18n/ko/CHANGELOG.md
+++ b/docs/i18n/ko/CHANGELOG.md
@@ -10,6 +10,7 @@
 
 ### 🔧 Bug Fixes & Refactors
 
+- **fix(translator):** treat `developer` role as system in OpenAI → Claude translation — `openAIToClaude` now extracts `developer`-role messages into `systemParts` (same as `system`) and filters them from the non-system message list, preventing identity context injected via the Responses API `developer` role from silently becoming an assistant turn when routing to a Claude-format provider. ([#2407](https://github.com/diegosouzapw/OmniRoute/issues/2407))
 - **fix(antigravity):** deduplicate `removeHeaderCaseInsensitive` — export canonical implementation from `antigravityClientProfile.ts` and remove the local copy in `antigravity.ts`; export `AntigravityCredentialsLike` type for cross-module use. (#2433 — thanks @Gi99lin)
 
 ### 🔒 Security Fixes
diff --git a/docs/i18n/mr/CHANGELOG.md b/docs/i18n/mr/CHANGELOG.md
index aaf1b4d10a..3833a2a49f 100644
--- a/docs/i18n/mr/CHANGELOG.md
+++ b/docs/i18n/mr/CHANGELOG.md
@@ -10,6 +10,7 @@
 
 ### 🔧 Bug Fixes & Refactors
 
+- **fix(translator):** treat `developer` role as system in OpenAI → Claude translation — `openAIToClaude` now extracts `developer`-role messages into `systemParts` (same as `system`) and filters them from the non-system message list, preventing identity context injected via the Responses API `developer` role from silently becoming an assistant turn when routing to a Claude-format provider. ([#2407](https://github.com/diegosouzapw/OmniRoute/issues/2407))
 - **fix(antigravity):** deduplicate `removeHeaderCaseInsensitive` — export canonical implementation from `antigravityClientProfile.ts` and remove the local copy in `antigravity.ts`; export `AntigravityCredentialsLike` type for cross-module use. (#2433 — thanks @Gi99lin)
 
 ### 🔒 Security Fixes
diff --git a/docs/i18n/ms/CHANGELOG.md b/docs/i18n/ms/CHANGELOG.md
index 0063a9049f..03a5294e8e 100644
--- a/docs/i18n/ms/CHANGELOG.md
+++ b/docs/i18n/ms/CHANGELOG.md
@@ -10,6 +10,7 @@
 
 ### 🔧 Bug Fixes & Refactors
 
+- **fix(translator):** treat `developer` role as system in OpenAI → Claude translation — `openAIToClaude` now extracts `developer`-role messages into `systemParts` (same as `system`) and filters them from the non-system message list, preventing identity context injected via the Responses API `developer` role from silently becoming an assistant turn when routing to a Claude-format provider. ([#2407](https://github.com/diegosouzapw/OmniRoute/issues/2407))
 - **fix(antigravity):** deduplicate `removeHeaderCaseInsensitive` — export canonical implementation from `antigravityClientProfile.ts` and remove the local copy in `antigravity.ts`; export `AntigravityCredentialsLike` type for cross-module use. (#2433 — thanks @Gi99lin)
 
 ### 🔒 Security Fixes
diff --git a/docs/i18n/nl/CHANGELOG.md b/docs/i18n/nl/CHANGELOG.md
index 53eadd469c..7661ed7778 100644
--- a/docs/i18n/nl/CHANGELOG.md
+++ b/docs/i18n/nl/CHANGELOG.md
@@ -10,6 +10,7 @@
 
 ### 🔧 Bug Fixes & Refactors
 
+- **fix(translator):** treat `developer` role as system in OpenAI → Claude translation — `openAIToClaude` now extracts `developer`-role messages into `systemParts` (same as `system`) and filters them from the non-system message list, preventing identity context injected via the Responses API `developer` role from silently becoming an assistant turn when routing to a Claude-format provider. ([#2407](https://github.com/diegosouzapw/OmniRoute/issues/2407))
 - **fix(antigravity):** deduplicate `removeHeaderCaseInsensitive` — export canonical implementation from `antigravityClientProfile.ts` and remove the local copy in `antigravity.ts`; export `AntigravityCredentialsLike` type for cross-module use. (#2433 — thanks @Gi99lin)
 
 ### 🔒 Security Fixes
diff --git a/docs/i18n/no/CHANGELOG.md b/docs/i18n/no/CHANGELOG.md
index e57770216e..bbf45715fc 100644
--- a/docs/i18n/no/CHANGELOG.md
+++ b/docs/i18n/no/CHANGELOG.md
@@ -10,6 +10,7 @@
 
 ### 🔧 Bug Fixes & Refactors
 
+- **fix(translator):** treat `developer` role as system in OpenAI → Claude translation — `openAIToClaude` now extracts `developer`-role messages into `systemParts` (same as `system`) and filters them from the non-system message list, preventing identity context injected via the Responses API `developer` role from silently becoming an assistant turn when routing to a Claude-format provider. ([#2407](https://github.com/diegosouzapw/OmniRoute/issues/2407))
 - **fix(antigravity):** deduplicate `removeHeaderCaseInsensitive` — export canonical implementation from `antigravityClientProfile.ts` and remove the local copy in `antigravity.ts`; export `AntigravityCredentialsLike` type for cross-module use. (#2433 — thanks @Gi99lin)
 
 ### 🔒 Security Fixes
diff --git a/docs/i18n/phi/CHANGELOG.md b/docs/i18n/phi/CHANGELOG.md
index 3140108a54..330a5e6c4e 100644
--- a/docs/i18n/phi/CHANGELOG.md
+++ b/docs/i18n/phi/CHANGELOG.md
@@ -10,6 +10,7 @@
 
 ### 🔧 Bug Fixes & Refactors
 
+- **fix(translator):** treat `developer` role as system in OpenAI → Claude translation — `openAIToClaude` now extracts `developer`-role messages into `systemParts` (same as `system`) and filters them from the non-system message list, preventing identity context injected via the Responses API `developer` role from silently becoming an assistant turn when routing to a Claude-format provider. ([#2407](https://github.com/diegosouzapw/OmniRoute/issues/2407))
 - **fix(antigravity):** deduplicate `removeHeaderCaseInsensitive` — export canonical implementation from `antigravityClientProfile.ts` and remove the local copy in `antigravity.ts`; export `AntigravityCredentialsLike` type for cross-module use. (#2433 — thanks @Gi99lin)
 
 ### 🔒 Security Fixes
diff --git a/docs/i18n/pl/CHANGELOG.md b/docs/i18n/pl/CHANGELOG.md
index eaf36aa02a..03638aeed7 100644
--- a/docs/i18n/pl/CHANGELOG.md
+++ b/docs/i18n/pl/CHANGELOG.md
@@ -10,6 +10,7 @@
 
 ### 🔧 Bug Fixes & Refactors
 
+- **fix(translator):** treat `developer` role as system in OpenAI → Claude translation — `openAIToClaude` now extracts `developer`-role messages into `systemParts` (same as `system`) and filters them from the non-system message list, preventing identity context injected via the Responses API `developer` role from silently becoming an assistant turn when routing to a Claude-format provider. ([#2407](https://github.com/diegosouzapw/OmniRoute/issues/2407))
 - **fix(antigravity):** deduplicate `removeHeaderCaseInsensitive` — export canonical implementation from `antigravityClientProfile.ts` and remove the local copy in `antigravity.ts`; export `AntigravityCredentialsLike` type for cross-module use. (#2433 — thanks @Gi99lin)
 
 ### 🔒 Security Fixes
diff --git a/docs/i18n/pt-BR/CHANGELOG.md b/docs/i18n/pt-BR/CHANGELOG.md
index 4421301aa4..804127e213 100644
--- a/docs/i18n/pt-BR/CHANGELOG.md
+++ b/docs/i18n/pt-BR/CHANGELOG.md
@@ -10,6 +10,7 @@
 
 ### 🔧 Bug Fixes & Refactors
 
+- **fix(translator):** treat `developer` role as system in OpenAI → Claude translation — `openAIToClaude` now extracts `developer`-role messages into `systemParts` (same as `system`) and filters them from the non-system message list, preventing identity context injected via the Responses API `developer` role from silently becoming an assistant turn when routing to a Claude-format provider. ([#2407](https://github.com/diegosouzapw/OmniRoute/issues/2407))
 - **fix(antigravity):** deduplicate `removeHeaderCaseInsensitive` — export canonical implementation from `antigravityClientProfile.ts` and remove the local copy in `antigravity.ts`; export `AntigravityCredentialsLike` type for cross-module use. (#2433 — thanks @Gi99lin)
 
 ### 🔒 Security Fixes
diff --git a/docs/i18n/pt/CHANGELOG.md b/docs/i18n/pt/CHANGELOG.md
index fef52a21a3..8cae4d40e6 100644
--- a/docs/i18n/pt/CHANGELOG.md
+++ b/docs/i18n/pt/CHANGELOG.md
@@ -10,6 +10,7 @@
 
 ### 🔧 Bug Fixes & Refactors
 
+- **fix(translator):** treat `developer` role as system in OpenAI → Claude translation — `openAIToClaude` now extracts `developer`-role messages into `systemParts` (same as `system`) and filters them from the non-system message list, preventing identity context injected via the Responses API `developer` role from silently becoming an assistant turn when routing to a Claude-format provider. ([#2407](https://github.com/diegosouzapw/OmniRoute/issues/2407))
 - **fix(antigravity):** deduplicate `removeHeaderCaseInsensitive` — export canonical implementation from `antigravityClientProfile.ts` and remove the local copy in `antigravity.ts`; export `AntigravityCredentialsLike` type for cross-module use. (#2433 — thanks @Gi99lin)
 
 ### 🔒 Security Fixes
diff --git a/docs/i18n/ro/CHANGELOG.md b/docs/i18n/ro/CHANGELOG.md
index b7bad0a634..8b7bef443b 100644
--- a/docs/i18n/ro/CHANGELOG.md
+++ b/docs/i18n/ro/CHANGELOG.md
@@ -10,6 +10,7 @@
 
 ### 🔧 Bug Fixes & Refactors
 
+- **fix(translator):** treat `developer` role as system in OpenAI → Claude translation — `openAIToClaude` now extracts `developer`-role messages into `systemParts` (same as `system`) and filters them from the non-system message list, preventing identity context injected via the Responses API `developer` role from silently becoming an assistant turn when routing to a Claude-format provider. ([#2407](https://github.com/diegosouzapw/OmniRoute/issues/2407))
 - **fix(antigravity):** deduplicate `removeHeaderCaseInsensitive` — export canonical implementation from `antigravityClientProfile.ts` and remove the local copy in `antigravity.ts`; export `AntigravityCredentialsLike` type for cross-module use. (#2433 — thanks @Gi99lin)
 
 ### 🔒 Security Fixes
diff --git a/docs/i18n/ru/CHANGELOG.md b/docs/i18n/ru/CHANGELOG.md
index 0943eaad04..e5377997f6 100644
--- a/docs/i18n/ru/CHANGELOG.md
+++ b/docs/i18n/ru/CHANGELOG.md
@@ -10,6 +10,7 @@
 
 ### 🔧 Bug Fixes & Refactors
 
+- **fix(translator):** treat `developer` role as system in OpenAI → Claude translation — `openAIToClaude` now extracts `developer`-role messages into `systemParts` (same as `system`) and filters them from the non-system message list, preventing identity context injected via the Responses API `developer` role from silently becoming an assistant turn when routing to a Claude-format provider. ([#2407](https://github.com/diegosouzapw/OmniRoute/issues/2407))
 - **fix(antigravity):** deduplicate `removeHeaderCaseInsensitive` — export canonical implementation from `antigravityClientProfile.ts` and remove the local copy in `antigravity.ts`; export `AntigravityCredentialsLike` type for cross-module use. (#2433 — thanks @Gi99lin)
 
 ### 🔒 Security Fixes
diff --git a/docs/i18n/sk/CHANGELOG.md b/docs/i18n/sk/CHANGELOG.md
index 9c99e46148..16c1837dab 100644
--- a/docs/i18n/sk/CHANGELOG.md
+++ b/docs/i18n/sk/CHANGELOG.md
@@ -10,6 +10,7 @@
 
 ### 🔧 Bug Fixes & Refactors
 
+- **fix(translator):** treat `developer` role as system in OpenAI → Claude translation — `openAIToClaude` now extracts `developer`-role messages into `systemParts` (same as `system`) and filters them from the non-system message list, preventing identity context injected via the Responses API `developer` role from silently becoming an assistant turn when routing to a Claude-format provider. ([#2407](https://github.com/diegosouzapw/OmniRoute/issues/2407))
 - **fix(antigravity):** deduplicate `removeHeaderCaseInsensitive` — export canonical implementation from `antigravityClientProfile.ts` and remove the local copy in `antigravity.ts`; export `AntigravityCredentialsLike` type for cross-module use. (#2433 — thanks @Gi99lin)
 
 ### 🔒 Security Fixes
diff --git a/docs/i18n/sv/CHANGELOG.md b/docs/i18n/sv/CHANGELOG.md
index 3bc1e118c1..8f94f974fc 100644
--- a/docs/i18n/sv/CHANGELOG.md
+++ b/docs/i18n/sv/CHANGELOG.md
@@ -10,6 +10,7 @@
 
 ### 🔧 Bug Fixes & Refactors
 
+- **fix(translator):** treat `developer` role as system in OpenAI → Claude translation — `openAIToClaude` now extracts `developer`-role messages into `systemParts` (same as `system`) and filters them from the non-system message list, preventing identity context injected via the Responses API `developer` role from silently becoming an assistant turn when routing to a Claude-format provider. ([#2407](https://github.com/diegosouzapw/OmniRoute/issues/2407))
 - **fix(antigravity):** deduplicate `removeHeaderCaseInsensitive` — export canonical implementation from `antigravityClientProfile.ts` and remove the local copy in `antigravity.ts`; export `AntigravityCredentialsLike` type for cross-module use. (#2433 — thanks @Gi99lin)
 
 ### 🔒 Security Fixes
diff --git a/docs/i18n/sw/CHANGELOG.md b/docs/i18n/sw/CHANGELOG.md
index 06d39af3a3..7e192256b3 100644
--- a/docs/i18n/sw/CHANGELOG.md
+++ b/docs/i18n/sw/CHANGELOG.md
@@ -10,6 +10,7 @@
 
 ### 🔧 Bug Fixes & Refactors
 
+- **fix(translator):** treat `developer` role as system in OpenAI → Claude translation — `openAIToClaude` now extracts `developer`-role messages into `systemParts` (same as `system`) and filters them from the non-system message list, preventing identity context injected via the Responses API `developer` role from silently becoming an assistant turn when routing to a Claude-format provider. ([#2407](https://github.com/diegosouzapw/OmniRoute/issues/2407))
 - **fix(antigravity):** deduplicate `removeHeaderCaseInsensitive` — export canonical implementation from `antigravityClientProfile.ts` and remove the local copy in `antigravity.ts`; export `AntigravityCredentialsLike` type for cross-module use. (#2433 — thanks @Gi99lin)
 
 ### 🔒 Security Fixes
diff --git a/docs/i18n/ta/CHANGELOG.md b/docs/i18n/ta/CHANGELOG.md
index 17d1a791aa..ae45a485d0 100644
--- a/docs/i18n/ta/CHANGELOG.md
+++ b/docs/i18n/ta/CHANGELOG.md
@@ -10,6 +10,7 @@
 
 ### 🔧 Bug Fixes & Refactors
 
+- **fix(translator):** treat `developer` role as system in OpenAI → Claude translation — `openAIToClaude` now extracts `developer`-role messages into `systemParts` (same as `system`) and filters them from the non-system message list, preventing identity context injected via the Responses API `developer` role from silently becoming an assistant turn when routing to a Claude-format provider. ([#2407](https://github.com/diegosouzapw/OmniRoute/issues/2407))
 - **fix(antigravity):** deduplicate `removeHeaderCaseInsensitive` — export canonical implementation from `antigravityClientProfile.ts` and remove the local copy in `antigravity.ts`; export `AntigravityCredentialsLike` type for cross-module use. (#2433 — thanks @Gi99lin)
 
 ### 🔒 Security Fixes
diff --git a/docs/i18n/te/CHANGELOG.md b/docs/i18n/te/CHANGELOG.md
index 53ba13e923..8d56c098cc 100644
--- a/docs/i18n/te/CHANGELOG.md
+++ b/docs/i18n/te/CHANGELOG.md
@@ -10,6 +10,7 @@
 
 ### 🔧 Bug Fixes & Refactors
 
+- **fix(translator):** treat `developer` role as system in OpenAI → Claude translation — `openAIToClaude` now extracts `developer`-role messages into `systemParts` (same as `system`) and filters them from the non-system message list, preventing identity context injected via the Responses API `developer` role from silently becoming an assistant turn when routing to a Claude-format provider. ([#2407](https://github.com/diegosouzapw/OmniRoute/issues/2407))
 - **fix(antigravity):** deduplicate `removeHeaderCaseInsensitive` — export canonical implementation from `antigravityClientProfile.ts` and remove the local copy in `antigravity.ts`; export `AntigravityCredentialsLike` type for cross-module use. (#2433 — thanks @Gi99lin)
 
 ### 🔒 Security Fixes
diff --git a/docs/i18n/th/CHANGELOG.md b/docs/i18n/th/CHANGELOG.md
index 84dc58e61d..a924af11a9 100644
--- a/docs/i18n/th/CHANGELOG.md
+++ b/docs/i18n/th/CHANGELOG.md
@@ -10,6 +10,7 @@
 
 ### 🔧 Bug Fixes & Refactors
 
+- **fix(translator):** treat `developer` role as system in OpenAI → Claude translation — `openAIToClaude` now extracts `developer`-role messages into `systemParts` (same as `system`) and filters them from the non-system message list, preventing identity context injected via the Responses API `developer` role from silently becoming an assistant turn when routing to a Claude-format provider. ([#2407](https://github.com/diegosouzapw/OmniRoute/issues/2407))
 - **fix(antigravity):** deduplicate `removeHeaderCaseInsensitive` — export canonical implementation from `antigravityClientProfile.ts` and remove the local copy in `antigravity.ts`; export `AntigravityCredentialsLike` type for cross-module use. (#2433 — thanks @Gi99lin)
 
 ### 🔒 Security Fixes
diff --git a/docs/i18n/tr/CHANGELOG.md b/docs/i18n/tr/CHANGELOG.md
index b08d753d90..3f7d715850 100644
--- a/docs/i18n/tr/CHANGELOG.md
+++ b/docs/i18n/tr/CHANGELOG.md
@@ -10,6 +10,7 @@
 
 ### 🔧 Bug Fixes & Refactors
 
+- **fix(translator):** treat `developer` role as system in OpenAI → Claude translation — `openAIToClaude` now extracts `developer`-role messages into `systemParts` (same as `system`) and filters them from the non-system message list, preventing identity context injected via the Responses API `developer` role from silently becoming an assistant turn when routing to a Claude-format provider. ([#2407](https://github.com/diegosouzapw/OmniRoute/issues/2407))
 - **fix(antigravity):** deduplicate `removeHeaderCaseInsensitive` — export canonical implementation from `antigravityClientProfile.ts` and remove the local copy in `antigravity.ts`; export `AntigravityCredentialsLike` type for cross-module use. (#2433 — thanks @Gi99lin)
 
 ### 🔒 Security Fixes
diff --git a/docs/i18n/uk-UA/CHANGELOG.md b/docs/i18n/uk-UA/CHANGELOG.md
index 83da9f3086..cb6f45b621 100644
--- a/docs/i18n/uk-UA/CHANGELOG.md
+++ b/docs/i18n/uk-UA/CHANGELOG.md
@@ -10,6 +10,7 @@
 
 ### 🔧 Bug Fixes & Refactors
 
+- **fix(translator):** treat `developer` role as system in OpenAI → Claude translation — `openAIToClaude` now extracts `developer`-role messages into `systemParts` (same as `system`) and filters them from the non-system message list, preventing identity context injected via the Responses API `developer` role from silently becoming an assistant turn when routing to a Claude-format provider. ([#2407](https://github.com/diegosouzapw/OmniRoute/issues/2407))
 - **fix(antigravity):** deduplicate `removeHeaderCaseInsensitive` — export canonical implementation from `antigravityClientProfile.ts` and remove the local copy in `antigravity.ts`; export `AntigravityCredentialsLike` type for cross-module use. (#2433 — thanks @Gi99lin)
 
 ### 🔒 Security Fixes
diff --git a/docs/i18n/ur/CHANGELOG.md b/docs/i18n/ur/CHANGELOG.md
index 6defbccea8..38cb13d0f8 100644
--- a/docs/i18n/ur/CHANGELOG.md
+++ b/docs/i18n/ur/CHANGELOG.md
@@ -10,6 +10,7 @@
 
 ### 🔧 Bug Fixes & Refactors
 
+- **fix(translator):** treat `developer` role as system in OpenAI → Claude translation — `openAIToClaude` now extracts `developer`-role messages into `systemParts` (same as `system`) and filters them from the non-system message list, preventing identity context injected via the Responses API `developer` role from silently becoming an assistant turn when routing to a Claude-format provider. ([#2407](https://github.com/diegosouzapw/OmniRoute/issues/2407))
 - **fix(antigravity):** deduplicate `removeHeaderCaseInsensitive` — export canonical implementation from `antigravityClientProfile.ts` and remove the local copy in `antigravity.ts`; export `AntigravityCredentialsLike` type for cross-module use. (#2433 — thanks @Gi99lin)
 
 ### 🔒 Security Fixes
diff --git a/docs/i18n/vi/CHANGELOG.md b/docs/i18n/vi/CHANGELOG.md
index eb1efe686c..891e6c0b1c 100644
--- a/docs/i18n/vi/CHANGELOG.md
+++ b/docs/i18n/vi/CHANGELOG.md
@@ -10,6 +10,7 @@
 
 ### 🔧 Bug Fixes & Refactors
 
+- **fix(translator):** treat `developer` role as system in OpenAI → Claude translation — `openAIToClaude` now extracts `developer`-role messages into `systemParts` (same as `system`) and filters them from the non-system message list, preventing identity context injected via the Responses API `developer` role from silently becoming an assistant turn when routing to a Claude-format provider. ([#2407](https://github.com/diegosouzapw/OmniRoute/issues/2407))
 - **fix(antigravity):** deduplicate `removeHeaderCaseInsensitive` — export canonical implementation from `antigravityClientProfile.ts` and remove the local copy in `antigravity.ts`; export `AntigravityCredentialsLike` type for cross-module use. (#2433 — thanks @Gi99lin)
 
 ### 🔒 Security Fixes
diff --git a/docs/i18n/zh-CN/CHANGELOG.md b/docs/i18n/zh-CN/CHANGELOG.md
index 3260144467..6139519cba 100644
--- a/docs/i18n/zh-CN/CHANGELOG.md
+++ b/docs/i18n/zh-CN/CHANGELOG.md
@@ -10,6 +10,7 @@
 
 ### 🔧 Bug Fixes & Refactors
 
+- **fix(translator):** treat `developer` role as system in OpenAI → Claude translation — `openAIToClaude` now extracts `developer`-role messages into `systemParts` (same as `system`) and filters them from the non-system message list, preventing identity context injected via the Responses API `developer` role from silently becoming an assistant turn when routing to a Claude-format provider. ([#2407](https://github.com/diegosouzapw/OmniRoute/issues/2407))
 - **fix(antigravity):** deduplicate `removeHeaderCaseInsensitive` — export canonical implementation from `antigravityClientProfile.ts` and remove the local copy in `antigravity.ts`; export `AntigravityCredentialsLike` type for cross-module use. (#2433 — thanks @Gi99lin)
 
 ### 🔒 Security Fixes
diff --git a/open-sse/translator/request/openai-to-claude.ts b/open-sse/translator/request/openai-to-claude.ts
index 8e7262c453..b2fc5910b5 100644
--- a/open-sse/translator/request/openai-to-claude.ts
+++ b/open-sse/translator/request/openai-to-claude.ts
@@ -206,16 +206,20 @@ export function openaiToClaudeRequest(model, body, stream) {
 
   if (body.messages && Array.isArray(body.messages)) {
     // Extract system messages (T15: handle both string and array content)
+    // Also treat "developer" role as system — OpenAI Responses API uses developer role
+    // for system-level instructions, and it must reach the Claude system field, not become an assistant turn.
     for (const msg of body.messages) {
-      if (msg.role === "system") {
+      if (msg.role === "system" || msg.role === "developer") {
         systemParts.push(
           typeof msg.content === "string" ? msg.content : normalizeContentToString(msg.content)
         );
       }
     }
 
-    // Filter out system messages for separate processing
-    const nonSystemMessages = body.messages.filter((m) => m.role !== "system");
+    // Filter out system/developer messages for separate processing
+    const nonSystemMessages = body.messages.filter(
+      (m) => m.role !== "system" && m.role !== "developer"
+    );
 
     // Process messages with merging logic
     // CRITICAL: tool_result must be in separate message immediately after tool_use
diff --git a/tests/unit/translator-openai-to-claude.test.ts b/tests/unit/translator-openai-to-claude.test.ts
index c7d77f69ab..579316bba3 100644
--- a/tests/unit/translator-openai-to-claude.test.ts
+++ b/tests/unit/translator-openai-to-claude.test.ts
@@ -498,3 +498,32 @@ test("OpenAI -> Claude handles assistant tool call messages without reasoning_co
   assert.ok(toolUseBlock, "expected tool_use block to be preserved");
   assert.equal(toolUseBlock.name, `${CLAUDE_OAUTH_TOOL_PREFIX}do_thing`);
 });
+
+test("OpenAI -> Claude treats developer role as system (fix for Responses API → Claude path)", () => {
+  const MARKER = "MAGIC_IDENTITY_847261";
+  const result = openaiToClaudeRequest(
+    "claude-sonnet-4-6",
+    {
+      messages: [
+        { role: "developer", content: `You are ${MARKER}` },
+        { role: "user", content: "What is your identity?" },
+      ],
+    },
+    true
+  );
+
+  // developer content must appear in the system field, not as an assistant turn
+  const systemText =
+    typeof result.system === "string" ? result.system : JSON.stringify(result.system);
+  assert.ok(systemText.includes(MARKER), "developer content must appear in Claude system field");
+
+  // No message in the messages array should contain the marker
+  for (const msg of result.messages) {
+    const msgStr = JSON.stringify(msg);
+    assert.ok(!msgStr.includes(MARKER), "developer content must NOT appear in messages array");
+  }
+
+  // Exactly one user message
+  const userMessages = result.messages.filter((m) => m.role === "user");
+  assert.equal(userMessages.length, 1, "expected exactly one user message");
+});