chore(changelog): add 2025-07-31 changelog for vapi OpenAPI spec

Author: quantstruct-canvas[bot]

fern/changelog/2025-07-31.mdx

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+---
+title: "Changelog – 2025-07-31"
+---
+
+# Changelog – 2025-07-31
+
+<Frame>
+
+## ⚡️ Major Updates
+
+### Dynamic Workflow Credentials
+
+<Check /> **Workflows now support dynamic `credentials`**. You can attach a variety of credential types (e.g., OpenAI, Azure, Google, Inworld, etc.) directly to a workflow. This enables per-workflow API key management and greater flexibility for multi-provider integrations.
+
+- **Benefit:** Credentials can now be scoped at the workflow level and override organization or assistant-level defaults. This is especially useful for teams managing multiple providers or environments.
+
+### Workflow Enhancements
+
+- **Background Sound:** Workflows now support a `backgroundSound` property, allowing you to specify ambient audio or custom background sound URLs for calls. This feature improves caller experience and can be tailored for different use cases.
+- **Keypad Input Plan:** Added `keypadInputPlan` to workflows, enabling advanced handling of DTMF/keypad input during calls.
+
+## 🧩 New Features & Additions
+
+### Provider Resource Management
+- **ProviderResource:** Introduces a new object for managing external provider resources (starting with 11Labs pronunciation dictionaries). This object includes metadata such as provider, resource type, and creation/update timestamps.
+- **Pronunciation Dictionary Support:** ElevenLabs voices now support `pronunciationDictionaryLocators`, making it easier to manage and apply pronunciation dictionaries to voice settings.
+
+### Variable Extraction Improvements
+- **VariableExtractionAlias:** You can now define custom variable aliases within `variableExtractionPlan`. This allows for more flexible and reusable variable mapping in workflow and tool schemas.
+
+### Assistant Hooks & Customer Speech Timeout
+- **CustomerSpeechTimeoutOptions:** Fine-tune how long the assistant waits for customer input before triggering actions. Includes options for timeout duration, maximum triggers, and reset behavior.
+- **AssistantHookCustomerSpeechTimeout:** New hook type lets you define actions (say or tool-call) that are triggered when the customer is silent for a configurable period.
+
+### Smart Endpointing (Beta)
+- **CustomEndpointingModelSmartEndpointingPlan:** Advanced configuration for when the assistant should start/stop speaking based on custom endpointing models. This allows precise control over interruption and response timing.
+
+## 🎤 Speech & Transcriber Updates
+
+- **AzureSpeechTranscriber:**
+  - Added `segmentationStrategy` and `segmentationSilenceTimeoutMs` for fine-grained phrase boundary detection.
+  - **Renamed** `segmentationMaxTimeMs` to `segmentationMaximumTimeMs` for clarity.
+  - Deprecated and removed the old property; use the new property for time-based segmentation.
+- **FallbackAzureSpeechTranscriber:**
+  - Same improvements as above, supporting fallback plans for transcription providers.
+
+## 🗑️ Removals & Deprecations
+
+- **Assistant/Workflow Properties:**
+  - Deprecated: `messagePlan` is now marked as deprecated on assistants and workflows. Please migrate logic to use hooks or other plans.
+  - Deprecated: `backgroundDenoisingEnabled` property is now deprecated. Use `backgroundSpeechDenoisingPlan` for advanced denoising.
+  - Removed: `silenceTimeoutSeconds` and related overrides have been removed from assistants and workflows. Use the new customer speech timeout hooks for equivalent functionality.
+- **Tool Functions:**
+  - The `function` property has been removed from most tool schemas (e.g., BashTool, DtmfTool, OutputTool, etc.). Use explicit tool configuration objects instead.
+- **JsonSchema:**
+  - Removed: `value` and `target` properties. Use `title`, `format`, or `pattern` for schema metadata.
+
+## 🧹 Minor & Internal
+
+- **Artifact Improvements:**
+  - Added `variableValues` to artifacts and node artifacts, exposing the final variable state after workflow execution.
+  - Deprecated: Several artifact properties (e.g., `recordingUrl`, `videoRecordingUrl`, `stereoRecordingUrl`) are now marked as deprecated in favor of consolidated fields.
+- **API Cleanup:**
+  - Removed legacy endpoints and tool discriminator mappings from the OpenAPI paths.
+  - Internal schemas for campaign pagination, provider resource management, and credential types have been refactored for clarity and extensibility.
+
+</Frame>
+
+---
+
+**Diff range:** 2025-07-25 → 2025-07-31
+
+For more details, see the [API reference](https://api.vapi.ai/api-json) and [docs](https://github.com/quantstruct/vapi-docs).