diff --git a/specification/ai/Foundry/datasets/routes.tsp b/specification/ai/Foundry/datasets/routes.tsp
index cf271c5c886d..8b53eda1f884 100644
--- a/specification/ai/Foundry/datasets/routes.tsp
+++ b/specification/ai/Foundry/datasets/routes.tsp
@@ -13,7 +13,15 @@ using Azure.ClientGenerator.Core;
 
 namespace Azure.AI.Projects;
 
-alias ListDatasetVersionsParameters = {};
+alias ListDatasetVersionsParameters = {
+  @doc("Filter datasets by taxonomy ID. Returns datasets where tags['taxonomy_id'] matches the provided value.")
+  @Http.query
+  taxonomyId?: string;
+
+  @doc("Filter datasets by evaluation run ID. Returns datasets where tags['eval_run_id'] matches the provided value.")
+  @Http.query
+  evalRunId?: string;
+};
 
 #suppress "@azure-tools/typespec-azure-core/use-standard-operations" "We are using service specific operation templates"
 @added(Versions.v2025_05_01)
diff --git a/specification/ai/Foundry/evaluation_taxonomies/models.tsp b/specification/ai/Foundry/evaluation_taxonomies/models.tsp
index 450f87a28e30..ddf575026af5 100644
--- a/specification/ai/Foundry/evaluation_taxonomies/models.tsp
+++ b/specification/ai/Foundry/evaluation_taxonomies/models.tsp
@@ -40,6 +40,9 @@ union EvaluationTaxonomyInputType {
 
   @doc("Policy.")
   policy: "policy",
+
+  @doc("Behavior-based taxonomy input for custom behavior definitions")
+  behavior: "behavior",
 }
 
 @added(Versions.v2025_11_15_preview)
@@ -65,6 +68,22 @@ model AgentTaxonomyInput extends EvaluationTaxonomyInput {
   riskCategories: RiskCategory[];
 }
 
+@added(Versions.v2025_11_15_preview)
+@removed(Versions.v1)
+@doc("Input configuration for the evaluation taxonomy when the input type is behavior.")
+model BehaviorTaxonomyInput extends EvaluationTaxonomyInput {
+  @doc("Input type of the evaluation taxonomy.")
+  type: EvaluationTaxonomyInputType.behavior;
+
+  @doc("Name of the behavior to evaluate")
+  behavior_name: string;
+
+  @doc("Detailed definition of the behavior (10-2000 characters)")
+  @minLength(10)
+  @maxLength(2000)
+  behavior_definition: string;
+}
+
 @added(Versions.v2025_11_15_preview)
 @removed(Versions.v1)
 @doc("Taxonomy category definition.")
@@ -101,9 +120,12 @@ model TaxonomySubCategory {
   @doc("Description of the taxonomy sub-category.")
   description?: string;
 
-  @doc("List of taxonomy items under this sub-category.")
+  @doc("Whether this sub-category is enabled for evaluation.")
   enabled: boolean;
 
+  @doc("List of subtopics for this sub-category.")
+  subtopics?: string[];
+
   @doc("Additional properties for the taxonomy sub-category.")
   properties?: Record<string>;
 }
diff --git a/specification/ai/Foundry/evaluation_taxonomies/routes.tsp b/specification/ai/Foundry/evaluation_taxonomies/routes.tsp
index 26988e23b71e..0cc0a985eece 100644
--- a/specification/ai/Foundry/evaluation_taxonomies/routes.tsp
+++ b/specification/ai/Foundry/evaluation_taxonomies/routes.tsp
@@ -3,6 +3,9 @@ import "@azure-tools/typespec-autorest";
 import "@typespec/versioning";
 import "@azure-tools/typespec-azure-core";
 import "./models.tsp";
+import "../datasets/models.tsp";
+import "../evaluators/models.tsp";
+import "../openai-evaluations/models.tsp";
 
 using TypeSpec.Http;
 using TypeSpec.Versioning;
@@ -73,4 +76,52 @@ interface EvaluationTaxonomies {
     },
     OkResponse<EvaluationTaxonomy>
   >;
+
+  @doc("List datasets generated from this taxonomy.")
+  @get
+  @route("/evaluationtaxonomies/{name}/datasets")
+  listDatasets is Azure.Core.Foundations.Operation<
+    {
+      @doc("The name of the evaluation taxonomy.")
+      @path
+      name: string;
+
+      @doc("Filter by taxonomy version.")
+      @query
+      version?: string;
+    },
+    Azure.Core.Page<DatasetVersion>
+  >;
+
+  @doc("List evaluation runs that used this taxonomy.")
+  @get
+  @route("/evaluationtaxonomies/{name}/runs")
+  listRuns is Azure.Core.Foundations.Operation<
+    {
+      @doc("The name of the evaluation taxonomy.")
+      @path
+      name: string;
+
+      @doc("Filter by taxonomy version.")
+      @query
+      version?: string;
+    },
+    AgentsPagedResult<EvalRun>
+  >;
+
+  @doc("List evaluators referencing this taxonomy.")
+  @get
+  @route("/evaluationtaxonomies/{name}/evaluators")
+  listEvaluators is Azure.Core.Foundations.Operation<
+    {
+      @doc("The name of the evaluation taxonomy.")
+      @path
+      name: string;
+
+      @doc("Filter by taxonomy version.")
+      @query
+      version?: string;
+    },
+    Azure.Core.Page<EvaluatorVersion>
+  >;
 }
diff --git a/specification/ai/Foundry/evaluators/models.tsp b/specification/ai/Foundry/evaluators/models.tsp
index 2ceb0b1ecfa6..dca3cc2ab392 100644
--- a/specification/ai/Foundry/evaluators/models.tsp
+++ b/specification/ai/Foundry/evaluators/models.tsp
@@ -60,6 +60,9 @@ union EvaluatorDefinitionType {
 
   @doc("OpenAI graders")
   openai_graders: "openai_graders",
+
+  @doc("Behavior-based definition that auto-creates a linked taxonomy")
+  behavior: "behavior",
 }
 
 #suppress "@azure-tools/typespec-azure-core/no-unknown"
@@ -101,6 +104,29 @@ model PromptBasedEvaluatorDefinition extends EvaluatorDefinition {
   prompt_text: string;
 }
 
+@doc("Behavior-based evaluator definition that auto-creates a linked taxonomy")
+@added(Versions.v2025_11_15_preview)
+@removed(Versions.v1)
+model BehaviorBasedEvaluatorDefinition extends EvaluatorDefinition {
+  type: EvaluatorDefinitionType.behavior;
+
+  @doc("Name of the behavior to evaluate")
+  behavior_name: string;
+
+  @doc("Detailed definition of the behavior (10-2000 characters)")
+  @minLength(10)
+  @maxLength(2000)
+  behavior_definition: string;
+
+  @doc("ID of the auto-created linked taxonomy (read-only, set by service)")
+  @visibility(Lifecycle.Read)
+  taxonomy_id?: string;
+
+  @doc("Current version of the linked taxonomy (read-only, set by service)")
+  @visibility(Lifecycle.Read)
+  taxonomy_version?: string;
+}
+
 @doc("Evaluator Definition")
 @resource("evaluators")
 @added(Versions.v2025_11_15_preview)
diff --git a/specification/ai/Foundry/evaluators/routes.tsp b/specification/ai/Foundry/evaluators/routes.tsp
index 8f5de3db47f0..df5ae0b64f68 100644
--- a/specification/ai/Foundry/evaluators/routes.tsp
+++ b/specification/ai/Foundry/evaluators/routes.tsp
@@ -17,6 +17,10 @@ alias ListEvaluatorVersionsParameters = {
   @Http.query
   type?: EvaluatorType | "all";
 
+  @doc("Filter evaluators by taxonomy ID. Returns only evaluators with definition.type='taxonomy' and matching taxonomy_id.")
+  @Http.query
+  taxonomyId?: string;
+
   @doc("A limit on the number of objects to be returned. Limit can range between 1 and 100, and the default is 20.")
   @Http.query
   limit?: int32 = 20;
diff --git a/specification/ai/Foundry/openai-evaluations/models.tsp b/specification/ai/Foundry/openai-evaluations/models.tsp
index ff79b1488d44..6483321c1030 100644
--- a/specification/ai/Foundry/openai-evaluations/models.tsp
+++ b/specification/ai/Foundry/openai-evaluations/models.tsp
@@ -198,6 +198,9 @@ model RedTeamTaxonomyItemGenerationParams extends RedTeamItemGenerationParams {
 
   /** The source from which JSONL content is read. */
   source: OpenAI.EvalJsonlFileContentSource;
+
+  /** Description of the application for context-aware seed generation. */
+  application_description?: string;
 }
 
 /** Represents the set of parameters used to control item generation operations. */