An event represents a message from either the user or agent.
name 
 
  string 
 
Identifier. The resource name of the event. Format: projects/{project}/locations/{location}/reasoningEngines/{reasoningEngine}/sessions/{session}/events/{event} 
.
content 
 
  object (  Content 
 
) 
 
Optional. Content of the event provided by the author.
invocationId 
 
  string 
 
Required. The invocation id of the event, multiple events can have the same invocation id.
actions 
 
  object (  EventActions 
 
) 
 
Optional. Actions executed by the agent.
errorCode 
 
  string 
 
Optional. Error code if the response is an error. code varies by model.
| JSON representation | 
|---|
| { "name" : string , "author" : string , "content" : { object ( | 
EventActions
Actions are parts of events that are executed by the agent.
skipSummarization 
 
  boolean 
 
Optional. If true, it won't call model to summarize function response. Only used for functionResponse event.
stateDelta 
 
  object (  Struct 
 
format) 
 
Optional. Indicates that the event is updating the state with the given delta.
artifactDelta 
 
  map (key: string, value: integer) 
 
Optional. Indicates that the event is updating an artifact. key is the filename, value is the version.
escalate 
 
  boolean 
 
Optional. The agent is escalating to a higher level agent.
requestedAuthConfigs 
 
  object (  Struct 
 
format) 
 
Optional. Will only be set by a tool response indicating tool request euc. Struct key is the function call id since one function call response (from model) could correspond to multiple function calls. Struct value is the required auth config, which can be another struct.
transferAgent 
 
  string 
 
Optional. If set, the event transfers to the specified agent.
| JSON representation | 
|---|
| { "skipSummarization" : boolean , "stateDelta" : { object } , "artifactDelta" : { string : integer , ... } , "escalate" : boolean , "requestedAuthConfigs" : { object } , "transferAgent" : string } | 
EventMetadata
metadata relating to a LLM response event.
partial 
 
  boolean 
 
Optional. Indicates whether the text content is part of a unfinished text stream. Only used for streaming mode and when the content is plain text.
turnComplete 
 
  boolean 
 
Optional. Indicates whether the response from the model is complete. Only used for streaming mode.
interrupted 
 
  boolean 
 
Optional. Flag indicating that LLM was interrupted when generating the content. Usually it's due to user interruption during a bidi streaming.
longRunningToolIds[] 
 
  string 
 
Optional. Set of ids of the long running function calls. Agent client will know from this field about which function call is long running. Only valid for function call event.
branch 
 
  string 
 
Optional. The branch of the event. The format is like agent_1.agent_2.agent_3, where agent_1 is the parent of agent_2, and agent_2 is the parent of agent_3. Branch is used when multiple child agents shouldn't see their siblings' conversation history.
| JSON representation | 
|---|
|  { 
 "groundingMetadata" 
 : 
 { 
 object (  | 
GroundingMetadata
metadata returned to client when grounding is enabled.
webSearchQueries[] 
 
  string 
 
Optional. Web search queries for the following-up web search.
retrievalQueries[] 
 
  string 
 
Optional. Queries executed by the retrieval tools.
groundingChunks[] 
 
  object (  GroundingChunk 
 
) 
 
List of supporting references retrieved from specified grounding source.
groundingSupports[] 
 
  object (  GroundingSupport 
 
) 
 
Optional. List of grounding support.
sourceFlaggingUris[] 
 
  object (  SourceFlaggingUri 
 
) 
 
Optional. Output only. List of source flagging uris. This is currently populated only for Google Maps grounding.
searchEntryPoint 
 
  object (  SearchEntryPoint 
 
) 
 
Optional. Google search entry for the following-up web searches.
| JSON representation | 
|---|
| { "webSearchQueries" : [ string ] , "retrievalQueries" : [ string ] , "groundingChunks" : [ { object ( | 
SearchEntryPoint
Google search entry point.
renderedContent 
 
  string 
 
Optional. Web content snippet that can be embedded in a web page or an app webview.
sdkBlob 
 
  string ( bytes 
format) 
 
Optional. Base64 encoded JSON representing array of <search term, search url> tuple.
A base64-encoded string.
| JSON representation | 
|---|
| { "renderedContent" : string , "sdkBlob" : string } | 
GroundingChunk
Grounding chunk.
chunk_type 
 
  Union type 
 
 chunk_type 
can be only one of the following:web 
 
  object (  Web 
 
) 
 
Grounding chunk from the web.
retrievedContext 
 
  object (  RetrievedContext 
 
) 
 
Grounding chunk from context retrieved by the retrieval tools.
maps 
 
  object (  Maps 
 
) 
 
Grounding chunk from Google Maps.
| JSON representation | 
|---|
| { // chunk_type "web" : { object ( | 
Web
Chunk from the web.
uri 
 
  string 
 
URI reference of the chunk.
title 
 
  string 
 
title of the chunk.
domain 
 
  string 
 
domain of the (original) URI.
| JSON representation | 
|---|
| { "uri" : string , "title" : string , "domain" : string } | 
RetrievedContext
Chunk from context retrieved by the retrieval tools.
context_details 
 
  Union type 
 
 context_details 
can be only one of the following:ragChunk 
 
  object (  RagChunk 
 
) 
 
Additional context for the RAG retrieval result. This is only populated when using the RAG retrieval tool.
uri 
 
  string 
 
URI reference of the attribution.
title 
 
  string 
 
title of the attribution.
text 
 
  string 
 
Text of the attribution.
documentName 
 
  string 
 
Output only. The full document name for the referenced Vertex AI Search document.
| JSON representation | 
|---|
|  { 
 // context_details 
 "ragChunk" 
 : 
 { 
 object (  | 
Maps
Chunk from Google Maps.
placeAnswerSources 
 
  object (  PlaceAnswerSources 
 
) 
 
Sources used to generate the place answer. This includes review snippets and photos that were used to generate the answer, as well as uris to flag content.
uri 
 
  string 
 
URI reference of the place.
title 
 
  string 
 
title of the place.
text 
 
  string 
 
Text of the place answer.
placeId 
 
  string 
 
This Place's resource name, in places/{placeId} 
format. Can be used to look up the Place.
| JSON representation | 
|---|
|  { 
 "placeAnswerSources" 
 : 
 { 
 object (  | 
PlaceAnswerSources
Sources used to generate the place answer.
reviewSnippets[] 
 
  object (  ReviewSnippet 
 
) 
 
Snippets of reviews that are used to generate the answer.
| JSON representation | 
|---|
|  { 
 "reviewSnippets" 
 : 
 [ 
 { 
 object (  | 
ReviewSnippet
Encapsulates a review snippet.
reviewId 
 
  string 
 
id of the review referencing the place.
googleMapsUri 
 
  string 
 
A link to show the review on Google Maps.
title 
 
  string 
 
title of the review.
| JSON representation | 
|---|
| { "reviewId" : string , "googleMapsUri" : string , "title" : string } | 
GroundingSupport
Grounding support.
groundingChunkIndices[] 
 
  integer 
 
A list of indices (into 'grounding_chunk') specifying the citations associated with the claim. For instance [1,3,4] means that grounding_chunk[1], grounding_chunk[3], grounding_chunk[4] are the retrieved content attributed to the claim.
confidenceScores[] 
 
  number 
 
confidence score of the support references. Ranges from 0 to 1. 1 is the most confident. For Gemini 2.0 and before, this list must have the same size as the groundingChunkIndices. For Gemini 2.5 and after, this list will be empty and should be ignored.
segment 
 
  object (  Segment 
 
) 
 
Segment of the content this support belongs to.
| JSON representation | 
|---|
|  { 
 "groundingChunkIndices" 
 : 
 [ 
 integer 
 ] 
 , 
 "confidenceScores" 
 : 
 [ 
 number 
 ] 
 , 
 "segment" 
 : 
 { 
 object (  | 
Segment
Segment of the content.
partIndex 
 
  integer 
 
Output only. The index of a Part object within its parent Content object.
startIndex 
 
  integer 
 
Output only. Start index in the given Part, measured in bytes. Offset from the start of the Part, inclusive, starting at zero.
endIndex 
 
  integer 
 
Output only. End index in the given Part, measured in bytes. Offset from the start of the Part, exclusive, starting at zero.
text 
 
  string 
 
Output only. The text corresponding to the segment from the response.
| JSON representation | 
|---|
| { "partIndex" : integer , "startIndex" : integer , "endIndex" : integer , "text" : string } | 
RetrievalMetadata
metadata related to retrieval in the grounding flow.
googleSearchDynamicRetrievalScore 
 
  number 
 
Optional. Score indicating how likely information from Google Search could help answer the prompt. The score is in the range [0, 1] 
, where 0 is the least likely and 1 is the most likely. This score is only populated when Google Search grounding and dynamic retrieval is enabled. It will be compared to the threshold to determine whether to trigger Google Search.
| JSON representation | 
|---|
| { "googleSearchDynamicRetrievalScore" : number } | 
SourceFlaggingUri
Source content flagging uri for a place or review. This is currently populated only for Google Maps grounding.
sourceId 
 
  string 
 
id of the place or review.
flagContentUri 
 
  string 
 
A link where users can flag a problem with the source (place or review).
| JSON representation | 
|---|
| { "sourceId" : string , "flagContentUri" : string } | 

