Reference tables for Copilot Studio YAML authoring: triggers, actions, variables, entities, Power Fx functions, templates. Preloaded by author and advisor agents.
Topics with OnRecognizedIntent have two routing mechanisms — which one matters depends on the orchestration mode:
modelDescription — used by generative orchestration (GenerativeActionsEnabled: true). The AI orchestrator reads this to decide routing. Primary mechanism for generative agents.
Trigger phrases (triggerQueries) — used by classic orchestration. Pattern-matched against the user's utterance. Secondary hints when generative orchestration is enabled.
System triggers (OnConversationStart, OnUnknownIntent, OnError, etc.) fire automatically and don't use either mechanism.
Kind
Purpose
OnRecognizedIntent
Trigger phrases matched
OnConversationStart
Conversation begins
OnUnknownIntent
No topic matched (fallback)
OnEscalate
User requests human agent
OnError
Error handling
OnSystemRedirect
Triggered by redirect only
OnSelectIntent
Multiple topics matched (disambiguation)
OnSignIn
Authentication required
OnToolSelected
Child agent invocation
OnKnowledgeRequested
Custom knowledge source search triggered (YAML-only, no UI)
OnGeneratedResponse
Intercept AI-generated response before sending
OnOutgoingMessage
Non-functional (2026-03-15) — exists in schema but does not fire at runtime. Do not use.
YAML-Only Features
These features work at runtime but are not visible in the Copilot Studio UI. Warn users that UI edits may silently remove them.
Feature
Notes
triggerCondition on knowledge sources
The UI only exposes this as an on/off toggle (=false to exclude from UniversalSearchTool). Arbitrary Power Fx expressions (e.g., =Global.UserDepartment = "HR") work at runtime but can only be set via YAML. Use with caution. (2026-03-16)
Action Types
Kind
Purpose
SendActivity
Send a message
Question
Ask user for input
SetVariable
Set/compute a variable (Power Fx expression, prefix =)
SetTextVariable
Set a text variable using template interpolation ({}). Useful for converting non-text types (e.g., Number) to text: "You have {Topic.Count} items"
ConditionGroup
Branching logic
BeginDialog
Call another topic
ReplaceDialog
Replace current topic
EndDialog
End current topic
CancelAllDialogs
Cancel all topics
ClearAllVariables
Clear variables
SearchAndSummarizeContent
Generative answers (grounded in knowledge)
AnswerQuestionWithAI
AI answer (conversation history + general knowledge only)
EditTable
Modify a collection
CSATQuestion
Customer satisfaction
LogCustomTelemetryEvent
Logging
OAuthInput
Sign-in prompt
SearchKnowledgeSources
Search knowledge sources (returns raw results, no AI summary)
CreateSearchQuery
AI-generated search query from user input
Connector Actions (TaskDialog)
Connector actions (kind: TaskDialog) invoke external connector operations. They are stored in actions/ and require a connection reference in connectionreferences.mcs.yml.
Use /add-action to create new actions from available connectors. The schema describes the structural properties of TaskDialog and InvokeConnectorTaskAction, but the specific inputs and outputs for each connector operation are connector-specific — use the connector lookup script (connector-lookup.bundle.js) to get the full operation details.
Action Structure
Field
Purpose
kind: TaskDialog
Identifies this as a connector action
inputs
Inputs: AutomaticTaskInput (AI-provided) or ManualTaskInput (fixed value)
modelDisplayName
Display name for AI orchestrator routing
modelDescription
Description for AI orchestrator routing
outputs
Output property names returned by the connector
action.kind
Always InvokeConnectorTaskAction for connector actions
action.connectionReference
Logical name of the connection (registered in connectionreferences.mcs.yml)
action.connectionProperties.mode
Maker (maker's credentials) or Invoker (end user's credentials)
action.operationId
The connector's specific operation identifier
outputMode
Usually All — exports all operation outputs
Input Types
Input Kind
Use When
Notes
AutomaticTaskInput
The AI orchestrator should provide the value based on context
Includes description for the AI to understand what to provide
ManualTaskInput
A fixed/hardcoded value (e.g., timezone, folder path)
Can only hardcode strings. Non-string values (IDs, enums) should be reviewed by the user after pushing
$-Prefixed Property Names (SharePoint, OData)
Some connectors (notably SharePoint) use OData parameters like $filter, $orderby, $top. These require special quoting in TaskDialog YAML — both single and double quotes:
"'$filter'" means: the outer "" are YAML string delimiters; the inner '' are part of the literal value sent to the runtime. Using $filter, "$filter", or '$filter' alone will fail.
InvokeConnectorAction (inline in topics) uses a different format — the parameters/ prefix with no inner single quotes:
AI-rewritten search query (available in OnKnowledgeRequested)
System.KeywordSearchQuery
Keyword version of search query (available in OnKnowledgeRequested)
System.SearchResults
Table to populate with custom search results — schema: Content, ContentLocation, Title (available in OnKnowledgeRequested)
System.ContinueResponse
Set to false in OnGeneratedResponse to suppress auto-send
System.Response.FormattedText
The AI-generated response text (available in OnGeneratedResponse)
Variable Scopes
Prefix
Scope
Lifetime
Topic.<name>
Topic variable
Current topic only
Global.<name>
Global variable
Entire conversation (defined in variables/ folder)
System.<name>
System variable
Built-in, read-only
Global variables are defined as YAML files in variables/<Name>.mcs.yml (kind: GlobalVariableComponent). aIVisibility accepts UseInAIContext (orchestrator can read and reason about the value) or Hidden (orchestrator unaware — use for flags and internal bookkeeping).
Prebuilt Entities
Entity
Use Case
BooleanPrebuiltEntity
Yes/No questions
NumberPrebuiltEntity
Numeric inputs
StringPrebuiltEntity
Free text
DateTimePrebuiltEntity
Date/time
EMailPrebuiltEntity
Email addresses
Power Fx Expression Reference
Only use functions from the supported list below. Copilot Studio supports a subset of Power Fx — using unsupported functions will cause errors.
