fix(schema): remove enum discriminators from invalid schemas

agent-client-protocol-schema/src/v1/elicitation.rs

@@ -730,7 +730,6 @@ fn other_multi_select_items_schema(schema: &mut Schema) {
 /// Items for a multi-select (array) property schema.
 #[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize, JsonSchema)]
 #[serde(tag = "type", rename_all = "snake_case")]
-#[schemars(extend("discriminator" = {"propertyName": "type"}))]
 #[non_exhaustive]
 pub enum MultiSelectItems {
     /// Multi-select string items with plain string values.
@@ -868,7 +867,6 @@ impl MultiSelectPropertySchema {
 /// Multi-select enums use the `Array` variant.
 #[derive(Debug, Clone, PartialEq, Serialize, Deserialize, JsonSchema)]
 #[serde(tag = "type", rename_all = "snake_case")]
-#[schemars(extend("discriminator" = {"propertyName": "type"}))]
 #[non_exhaustive]
 pub enum ElicitationPropertySchema {
     /// String property (or single-select enum when `enum`/`oneOf` is set).
@@ -1517,7 +1515,6 @@ impl CreateElicitationRequest {
 /// The mode of elicitation, determining how user input is collected.
 #[derive(Debug, Clone, Serialize, Deserialize, JsonSchema, PartialEq)]
 #[serde(tag = "mode", rename_all = "snake_case")]
-#[schemars(extend("discriminator" = {"propertyName": "mode"}))]
 #[non_exhaustive]
 pub enum ElicitationMode {
     /// Form-based elicitation where the client renders a form from the provided schema.
@@ -1798,7 +1795,6 @@ impl CreateElicitationResponse {
 /// The user's action in response to an elicitation.
 #[derive(Debug, Clone, Serialize, Deserialize, JsonSchema, PartialEq)]
 #[serde(tag = "action", rename_all = "snake_case")]
-#[schemars(extend("discriminator" = {"propertyName": "action"}))]
 #[non_exhaustive]
 pub enum ElicitationAction {
     /// The user accepted and provided content.

agent-client-protocol-schema/src/v2/agent.rs

@@ -1481,7 +1481,6 @@ impl ResumeSessionRequest {
 /// Replay includes the position identified by the cursor.
 #[derive(Debug, Clone, Serialize, Deserialize, JsonSchema, PartialEq, Eq)]
 #[serde(tag = "type", rename_all = "snake_case")]
-#[schemars(extend("discriminator" = {"propertyName": "type"}))]
 #[non_exhaustive]
 pub enum ReplayFrom {
     /// Replay the whole conversation from its first replayable entry.
@@ -2337,7 +2336,6 @@ pub enum SessionConfigOptionCategory {
 /// Type-specific session configuration option payload.
 #[derive(Debug, Clone, Serialize, Deserialize, JsonSchema, PartialEq, Eq)]
 #[serde(tag = "type", rename_all = "snake_case")]
-#[schemars(extend("discriminator" = {"propertyName": "type"}))]
 #[non_exhaustive]
 pub enum SessionConfigKind {
     /// Single-value selector (dropdown).
@@ -2539,7 +2537,6 @@ impl SessionConfigOption {
 /// text option would get its own variant.
 #[derive(Debug, Clone, Serialize, JsonSchema, PartialEq, Eq)]
 #[serde(tag = "type", rename_all = "snake_case")]
-#[schemars(extend("discriminator" = {"propertyName": "type"}))]
 #[non_exhaustive]
 pub enum SessionConfigOptionValue {
     /// A [`SessionConfigValueId`] string value (`type: "id"`).
@@ -2849,7 +2846,6 @@ impl SetSessionConfigOptionResponse {
 /// See protocol docs: [MCP Servers](https://agentclientprotocol.com/protocol/session-setup#mcp-servers)
 #[derive(Debug, Clone, Serialize, Deserialize, JsonSchema, PartialEq, Eq)]
 #[serde(tag = "type", rename_all = "snake_case")]
-#[schemars(extend("discriminator" = {"propertyName": "type"}))]
 #[non_exhaustive]
 pub enum McpServer {
     /// HTTP transport configuration

agent-client-protocol-schema/src/v2/client.rs

@@ -66,7 +66,7 @@
 }
 
 impl UpdateSessionNotification {
     /// Builds [`SessionNotification`] with the required notification fields set; optional fields start unset or empty.
     #[must_use]
     pub fn new(session_id: impl Into<SessionId>, update: SessionUpdate) -> Self {
         Self {
@@ -95,7 +95,6 @@
 /// See protocol docs: [Agent Reports Output](https://agentclientprotocol.com/protocol/prompt-lifecycle#3-agent-reports-output)
 #[derive(Debug, Clone, Serialize, Deserialize, JsonSchema, PartialEq)]
 #[serde(tag = "sessionUpdate", rename_all = "snake_case")]
-#[schemars(extend("discriminator" = {"propertyName": "sessionUpdate"}))]
 #[non_exhaustive]
 pub enum SessionUpdate {
     /// A chunk of the user's message being streamed.
@@ -459,7 +458,6 @@
 /// that the session is idle, or that progress is blocked on user action.
 #[derive(Debug, Clone, Serialize, Deserialize, JsonSchema, PartialEq)]
 #[serde(tag = "state", rename_all = "snake_case")]
-#[schemars(extend("discriminator" = {"propertyName": "state"}))]
 #[non_exhaustive]
 pub enum StateUpdate {
     /// The agent is actively processing work in the session.
@@ -1131,7 +1129,6 @@
 /// The input specification for a command.
 #[derive(Debug, Clone, Serialize, Deserialize, JsonSchema, PartialEq, Eq)]
 #[serde(tag = "type", rename_all = "snake_case")]
-#[schemars(extend("discriminator" = {"propertyName": "type"}))]
 #[non_exhaustive]
 pub enum AvailableCommandInput {
     /// All text that was typed after the command name is provided as input.
@@ -1360,7 +1357,6 @@
 /// The operation requiring permission.
 #[derive(Debug, Clone, Serialize, Deserialize, JsonSchema, PartialEq)]
 #[serde(tag = "type", rename_all = "snake_case")]
-#[schemars(extend("discriminator" = {"propertyName": "type"}))]
 #[non_exhaustive]
 pub enum RequestPermissionSubject {
     /// Permission is requested before executing a tool call.
@@ -1609,7 +1605,6 @@
 /// The outcome of a permission request.
 #[derive(Debug, Clone, Serialize, Deserialize, JsonSchema, PartialEq, Eq)]
 #[serde(tag = "outcome", rename_all = "snake_case")]
-#[schemars(extend("discriminator" = {"propertyName": "outcome"}))]
 #[non_exhaustive]
 pub enum RequestPermissionOutcome {
     /// Active session work was cancelled before the user responded.

agent-client-protocol-schema/src/v2/content.rs

@@ -35,7 +35,6 @@ use crate::{IntoOption, SkipListener};
 /// See protocol docs: [Content](https://agentclientprotocol.com/protocol/content)
 #[derive(Debug, Clone, PartialEq, Deserialize, Serialize, JsonSchema)]
 #[serde(tag = "type", rename_all = "snake_case")]
-#[schemars(extend("discriminator" = {"propertyName": "type"}))]
 #[non_exhaustive]
 pub enum ContentBlock {
     /// Text content. May be plain text or formatted with Markdown.

agent-client-protocol-schema/src/v2/elicitation.rs

@@ -730,7 +730,6 @@ fn other_multi_select_items_schema(schema: &mut Schema) {
 /// Items for a multi-select (array) property schema.
 #[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize, JsonSchema)]
 #[serde(tag = "type", rename_all = "snake_case")]
-#[schemars(extend("discriminator" = {"propertyName": "type"}))]
 #[non_exhaustive]
 pub enum MultiSelectItems {
     /// Multi-select string items with plain string values.
@@ -871,7 +870,6 @@ impl MultiSelectPropertySchema {
 /// Multi-select enums use the `Array` variant.
 #[derive(Debug, Clone, PartialEq, Serialize, Deserialize, JsonSchema)]
 #[serde(tag = "type", rename_all = "snake_case")]
-#[schemars(extend("discriminator" = {"propertyName": "type"}))]
 #[non_exhaustive]
 pub enum ElicitationPropertySchema {
     /// String property (or single-select enum when `enum`/`oneOf` is set).
@@ -1503,7 +1501,6 @@ impl CreateElicitationRequest {
 /// The mode of elicitation, determining how user input is collected.
 #[derive(Debug, Clone, Serialize, Deserialize, JsonSchema, PartialEq)]
 #[serde(tag = "mode", rename_all = "snake_case")]
-#[schemars(extend("discriminator" = {"propertyName": "mode"}))]
 #[non_exhaustive]
 pub enum ElicitationMode {
     /// Form-based elicitation where the client renders a form from the provided schema.
@@ -1763,7 +1760,6 @@ impl CreateElicitationResponse {
 /// The user's action in response to an elicitation.
 #[derive(Debug, Clone, Serialize, Deserialize, JsonSchema, PartialEq)]
 #[serde(tag = "action", rename_all = "snake_case")]
-#[schemars(extend("discriminator" = {"propertyName": "action"}))]
 #[non_exhaustive]
 pub enum ElicitationAction {
     /// The user accepted and provided content.

agent-client-protocol-schema/src/v2/nes.rs

@@ -2352,7 +2352,6 @@ impl SuggestNesResponse {
 /// A suggestion returned by the agent.
 #[derive(Debug, Clone, Serialize, Deserialize, JsonSchema, PartialEq, Eq)]
 #[serde(tag = "kind", rename_all = "camelCase")]
-#[schemars(extend("discriminator" = {"propertyName": "kind"}))]
 #[non_exhaustive]
 pub enum NesSuggestion {
     /// A text edit suggestion.

agent-client-protocol-schema/src/v2/plan.rs

@@ -74,7 +74,6 @@ impl PlanUpdate {
 /// Updated content for a plan.
 #[derive(Debug, Clone, Serialize, Deserialize, JsonSchema, PartialEq, Eq)]
 #[serde(tag = "type", rename_all = "snake_case")]
-#[schemars(extend("discriminator" = {"propertyName": "type"}))]
 #[non_exhaustive]
 pub enum PlanUpdateContent {
     /// Structured plan entries.

agent-client-protocol-schema/src/v2/tool_call.rs

@@ -347,7 +347,6 @@ pub enum ToolCallStatus {
 /// See protocol docs: [Content](https://agentclientprotocol.com/protocol/tool-calls#content)
 #[derive(Debug, Clone, PartialEq, Serialize, Deserialize, JsonSchema)]
 #[serde(tag = "type", rename_all = "snake_case")]
-#[schemars(extend("discriminator" = {"propertyName": "type"}))]
 #[non_exhaustive]
 pub enum ToolCallContent {
     /// Standard content block (text, images, resources).
@@ -738,7 +737,6 @@ impl DiffChange {
 /// File operation for a [`DiffChange`].
 #[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize, JsonSchema)]
 #[serde(tag = "operation", rename_all = "snake_case")]
-#[schemars(extend("discriminator" = {"propertyName": "operation"}))]
 #[non_exhaustive]
 pub enum DiffChangeOperation {
     /// A file was added.

schema/v1/schema.unstable.json

@@ -1483,9 +1483,6 @@
           }
         }
       ],
-      "discriminator": {
-        "propertyName": "mode"
-      },
       "required": ["message"],
       "x-side": "client",
       "x-method": "elicitation/create"
@@ -1739,10 +1736,7 @@
           },
           "additionalProperties": true
         }
-      ],
-      "discriminator": {
-        "propertyName": "type"
-      }
+      ]
     },
     "StringFormat": {
       "description": "String format types for string properties in elicitation schemas.",
@@ -2021,10 +2015,7 @@
             }
           ]
         }
-      ],
-      "discriminator": {
-        "propertyName": "type"
-      }
+      ]
     },
     "StringMultiSelectItems": {
       "description": "String item schema for multi-select enum properties.",
@@ -8255,9 +8246,6 @@
           "additionalProperties": true
         }
       ],
-      "discriminator": {
-        "propertyName": "action"
-      },
       "x-side": "client",
       "x-method": "elicitation/create"
     },

schema/v2/schema.json

@@ -625,10 +625,7 @@
           },
           "additionalProperties": true
         }
-      ],
-      "discriminator": {
-        "propertyName": "type"
-      }
+      ]
     },
     "ToolCallUpdate": {
       "description": "Represents an upsert for a tool call that the language model has requested.\n\nTool calls are actions that the agent executes on behalf of the language model,\nsuch as reading files, executing code, or fetching data from external sources.\n\nOnly [`ToolCallUpdate::tool_call_id`] is required. Other fields have patch semantics:\nomitted fields leave the existing tool call value unchanged, `null` clears or\nunsets the value, and concrete values replace the previous value. For\ncollection fields, concrete arrays replace the previous collection, and both\n`null` and `[]` clear the collection. When a client receives a tool call ID it\nhas not seen before, omitted fields use client defaults.\n\nSee protocol docs: [Tool Calls](https://agentclientprotocol.com/protocol/v2/tool-calls)",
@@ -872,10 +869,7 @@
           },
           "additionalProperties": true
         }
-      ],
-      "discriminator": {
-        "propertyName": "type"
-      }
+      ]
     },
     "ContentBlock": {
       "description": "Content blocks represent displayable information in the Agent Client Protocol.\n\nThey provide a structured way to handle various types of user-facing content—whether\nit's text from language models, images for analysis, or embedded resources for context.\n\nContent blocks appear in:\n- User prompts sent via `session/prompt`\n- Language model output reported through `session/update` notifications as\n  message updates or streamed chunks\n- Progress updates and results from tool calls\n\nThis structure is compatible with the Model Context Protocol (MCP), enabling\nagents to seamlessly forward content from MCP tool outputs without transformation.\n\nSee protocol docs: [Content](https://agentclientprotocol.com/protocol/v2/content)",
@@ -1027,10 +1021,7 @@
           },
           "additionalProperties": true
         }
-      ],
-      "discriminator": {
-        "propertyName": "type"
-      }
+      ]
     },
     "Annotations": {
       "description": "Optional annotations for the client. The client can use annotations to inform how objects are used or displayed",
@@ -1620,10 +1611,7 @@
           },
           "additionalProperties": true
         }
-      ],
-      "discriminator": {
-        "propertyName": "operation"
-      }
+      ]
     },
     "DiffFileType": {
       "description": "Kind of file content represented by a diff change.",
@@ -2642,10 +2630,7 @@
           },
           "additionalProperties": true
         }
-      ],
-      "discriminator": {
-        "propertyName": "type"
-      }
+      ]
     },
     "SessionConfigId": {
       "description": "Unique identifier for a session configuration option.",
@@ -3522,10 +3507,7 @@
           },
           "additionalProperties": true
         }
-      ],
-      "discriminator": {
-        "propertyName": "sessionUpdate"
-      }
+      ]
     },
     "MessageId": {
       "description": "Unique identifier for a message within a session.",
@@ -3831,10 +3813,7 @@
           },
           "additionalProperties": true
         }
-      ],
-      "discriminator": {
-        "propertyName": "state"
-      }
+      ]
     },
     "ToolCallContentChunk": {
       "description": "A streamed item of tool-call content.\n\nTool-call content chunks append one [`ToolCallContent`] item to the current\ncontent for the matching [`ToolCallId`]. Agents can use\n[`ToolCallUpdate::content`] when they need to replace the whole content\ncollection instead.",
@@ -3939,10 +3918,7 @@
           },
           "additionalProperties": true
         }
-      ],
-      "discriminator": {
-        "propertyName": "type"
-      }
+      ]
     },
     "PlanId": {
       "description": "Unique identifier for a plan within a session.",
@@ -4161,10 +4137,7 @@
           },
           "additionalProperties": true
         }
-      ],
-      "discriminator": {
-        "propertyName": "type"
-      }
+      ]
     },
     "TextCommandInput": {
       "description": "All text that was typed after the command name is provided as input.",
@@ -4644,10 +4617,7 @@
           },
           "additionalProperties": true
         }
-      ],
-      "discriminator": {
-        "propertyName": "type"
-      }
+      ]
     },
     "HttpHeader": {
       "description": "An HTTP header to set when making requests to the MCP server.",
@@ -4909,10 +4879,7 @@
           },
           "additionalProperties": true
         }
-      ],
-      "discriminator": {
-        "propertyName": "type"
-      }
+      ]
     },
     "ReplayFromStart": {
       "description": "Inclusive replay cursor requesting replay from the start of the conversation.",
@@ -5053,9 +5020,6 @@
           "additionalProperties": true
         }
       ],
-      "discriminator": {
-        "propertyName": "type"
-      },
       "x-side": "agent",
       "x-method": "session/set_config_option"
     },
@@ -5248,10 +5212,7 @@
           },
           "additionalProperties": true
         }
-      ],
-      "discriminator": {
-        "propertyName": "outcome"
-      }
+      ]
     },
     "SelectedPermissionOutcome": {
       "description": "The user selected one of the provided options.",