Add changelog for 2025-08-21

fern/changelog/2025-08-14.mdx

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+1. **Handoff Tool and Dynamic Agent Routing**: You can now hand off conversations when building multi-agent systems with [`Assistant.model.tools[type=handoff]`](https://api.vapi.ai/api#:~:text=HandoffTool). Supported destinations include:
+- **Assistant Destinations**: Directly hand off to a specific assistant by assistantId or assistantName.
+- **Dynamic Destinations**: Route handoffs dynamically via a webhook to your server, which can determine the destination assistant in real time. Custom parameters such as customer intent, sentiment, or area code can be passed to the webhook for advanced routing logic.
+- **Multiple Destinations**: Support for both single handoff destination per tool with multiple tools (recommended for OpenAI) and multiple handoff destinations with one tool (recommended for Anthropic).
+
+You can read more about how to configure the handoff tool in the [API Reference](https://api.vapi.ai/api#:~:text=HandoffTool)
+
+2. **Context Engineering for Handoffs**: When handing off a conversation, you can now control what context is passed to the next assistant:
+- **All Messages**: Pass the entire conversation history. Refer to [Context Engineering Plan All](https://api.vapi.ai/api#:~:text=ContextEngineeringPlanAll)
+- **Last N Messages**: Pass only the most recent N messages. Refer to [Context Engineering Plan LastNMessages](https://api.vapi.ai/api#:~:text=ContextEngineeringPlanLastNMessages)
+- **None**: Pass no prior context. Refer to [Context Engineering Plan None](https://api.vapi.ai/api#:~:text=ContextEngineeringPlanNone)
+This gives you fine-grained control over privacy, relevance, and prompt size during agent transitions.
+
+3. **Message Metadata**: [Tool Messages](https://api.vapi.ai/api#:~:text=ToolMessage), [Assistant Messages](https://api.vapi.ai/api#:~:text=AssistantMessage), and [Developer Messages](https://api.vapi.ai/api#:~:text=DeveloperMessage) objects now support an optional metadata field, allowing you to attach arbitrary metadata to messages for downstream processing or analytics.
+
+4. **Pagination Meta Enhancement**: You can now reference `itemsBeyondRetention` boolean in paginated responses to indicate if additional items exist beyond the retention window.

fern/changelog/2025-08-21.mdx

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+1. **Enhanced Artifact Plans**: All [`Artifact Plans`](https://api.vapi.ai/api#:~:text=ArtifactPlan) now support the following properties:
+- **`loggingEnabled`** - Toggle to enable call logs
+- **`loggingPath`** - Custom path for call log uploads
+- **`structuredOutputs`** - Toggle for structured output extraction
+
+2. **Enhanced Artifact Management**: You can now extract structured data during calls with the new `structuredOutputs` property in [`Artifact`](https://api.vapi.ai/api#:~:text=Artifact).
+
+3. **Improved Cost Analysis**: You can now view detailed call costs with new fields in [`Analysis Cost Breakdown`](https://api.vapi.ai/api#:~:text=AnalysisCostBreakdown):
+- **`structuredOutput`** - Cost for structured output evaluation
+- **`structuredOutputPromptTokens`** - Prompt tokens for structured output
+- **`structuredOutputCompletionTokens`** - Completion tokens for structured output
+
+4. **Phone Number Hooks**: You can now configure hooks for call ending events with the new [`Call Ending hook for phone numbers`](https://api.vapi.ai/api#:~:text=PhoneNumberHookCallEnding) and exclude events to exclude from the hook with [`the relevant filter`](https://api.vapi.ai/api#:~:text=PhoneNumberCallEndingHookFilter)