diff --git a/changelog/3855.added.2.md b/changelog/3855.added.2.md
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+- Added optional `llm` field to `LLMContextSummarizationConfig` for routing summarization to a dedicated LLM service (e.g., a cheaper/faster model) instead of the pipeline's primary model.
diff --git a/changelog/3855.added.3.md b/changelog/3855.added.3.md
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+- Added `summarization_timeout` to `LLMContextSummarizationConfig` (default 120s) to prevent hung LLM calls from permanently blocking future summarizations.
diff --git a/changelog/3855.added.4.md b/changelog/3855.added.4.md
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+- Added `on_summary_applied` event to `LLMContextSummarizer` for observability, providing message counts before and after context summarization.
diff --git a/changelog/3855.added.md b/changelog/3855.added.md
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+- Added `summary_message_template` to `LLMContextSummarizationConfig` for customizing how summaries are formatted when injected into context (e.g., wrapping in XML tags).
diff --git a/changelog/3855.changed.md b/changelog/3855.changed.md
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+- Updated context summarization to use `user` role instead of `assistant` for summary messages.