feat(unstable-v2): tighten v2 field validation

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

@@ -810,6 +810,7 @@ pub struct AuthMethodEnvVar {
     /// Optional link to a page where the user can obtain their credentials.
     #[serde_as(deserialize_as = "DefaultOnError")]
     #[schemars(extend("x-deserialize-default-on-error" = true))]
+    #[schemars(url)]
     #[serde(default)]
     pub link: Option<String>,
     /// The _meta property is reserved by ACP to allow clients and agents to attach additional
@@ -2013,7 +2014,7 @@ pub struct SessionInfo {
     pub title: Option<String>,
     /// ISO 8601 timestamp of last activity
     #[serde_as(deserialize_as = "DefaultOnError")]
-    #[schemars(extend("x-deserialize-default-on-error" = true))]
+    #[schemars(extend("x-deserialize-default-on-error" = true, "format" = "date-time"))]
     #[serde(default)]
     pub updated_at: Option<String>,
     /// The _meta property is reserved by ACP to allow clients and agents to attach additional
@@ -3612,6 +3613,7 @@ pub struct ProviderCurrentConfig {
     /// Protocol currently used by this provider.
     pub api_type: LlmProtocol,
     /// Base URL currently used by this provider.
+    #[schemars(url)]
     pub base_url: String,
     /// The _meta property is reserved by ACP to allow clients and agents to attach additional
     /// metadata to their interactions. Implementations MUST NOT make assumptions about values at
@@ -3853,6 +3855,7 @@ pub struct SetProviderRequest {
     /// Protocol type for this provider.
     pub api_type: LlmProtocol,
     /// Base URL for requests sent through this provider.
+    #[schemars(url)]
     pub base_url: String,
     /// Full headers map for this provider.
     /// May include authorization, routing, or other integration-specific headers.

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 {
@@ -341,7 +341,7 @@
     pub title: MaybeUndefined<String>,
     /// ISO 8601 timestamp of last activity. Set to null to clear.
     #[serde_as(deserialize_as = "DefaultOnError")]
-    #[schemars(extend("x-deserialize-default-on-error" = true))]
+    #[schemars(extend("x-deserialize-default-on-error" = true, "format" = "date-time"))]
     #[serde(default, skip_serializing_if = "MaybeUndefined::is_undefined")]
     pub updated_at: MaybeUndefined<String>,
     /// The _meta property is reserved by ACP to allow clients and agents to attach additional
@@ -710,6 +710,7 @@
     /// Total cumulative cost for session.
     pub amount: f64,
     /// ISO 4217 currency code (e.g., "USD", "EUR").
+    #[schemars(pattern(r"^[A-Z]{3}$"))]
     pub currency: String,
     /// The _meta property is reserved by ACP to allow clients and agents to attach additional
     /// metadata to their interactions. Implementations MUST NOT make assumptions about values at
@@ -1297,6 +1298,8 @@
     #[serde(default)]
     pub subject: Option<RequestPermissionSubject>,
     /// Available permission options for the user to choose from.
+    /// Must contain at least one option.
+    #[schemars(length(min = 1))]
     pub options: Vec<PermissionOption>,
     /// The _meta property is reserved by ACP to allow clients and agents to attach additional
     /// metadata to their interactions. Implementations MUST NOT make assumptions about values at

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

@@ -742,8 +742,10 @@ pub struct Annotations {
     #[serde(default)]
     pub audience: Option<Vec<Role>>,
     /// Timestamp indicating when the underlying resource was last modified.
+    ///
+    /// Must be an ISO 8601 formatted string (e.g., "2025-01-12T15:00:58Z").
     #[serde_as(deserialize_as = "DefaultOnError")]
-    #[schemars(extend("x-deserialize-default-on-error" = true))]
+    #[schemars(extend("x-deserialize-default-on-error" = true, "format" = "date-time"))]
     #[serde(default)]
     pub last_modified: Option<String>,
     /// Relative importance of this content when clients choose what to surface.
@@ -984,6 +986,7 @@ mod tests {
 
         assert_eq!(json["properties"]["priority"]["minimum"], 0);
         assert_eq!(json["properties"]["priority"]["maximum"], 1);
+        assert_eq!(json["properties"]["lastModified"]["format"], "date-time");
     }
 
     #[test]

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

@@ -142,6 +142,7 @@ pub struct StringPropertySchema {
     #[serde(default)]
     pub max_length: Option<u32>,
     /// Pattern the string must match.
+    #[schemars(extend("format" = "regex"))]
     #[serde(default)]
     pub pattern: Option<String>,
     /// String format.
@@ -153,10 +154,14 @@ pub struct StringPropertySchema {
     #[serde(default)]
     pub default: Option<String>,
     /// Enum values for untitled single-select enums.
+    /// Must contain at least one value when present.
+    #[schemars(length(min = 1))]
     #[serde(default)]
     #[serde(rename = "enum")]
     pub enum_values: Option<Vec<String>>,
     /// Titled enum options for titled single-select enums.
+    /// Must contain at least one option when present.
+    #[schemars(length(min = 1))]
     #[serde(default)]
     #[serde(rename = "oneOf")]
     pub one_of: Option<Vec<EnumOption>>,
@@ -558,7 +563,8 @@ impl BooleanPropertySchema {
 #[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize, JsonSchema)]
 #[non_exhaustive]
 pub struct StringMultiSelectItems {
-    /// Allowed enum values.
+    /// Allowed enum values. Must contain at least one value.
+    #[schemars(length(min = 1))]
     #[serde(rename = "enum")]
     pub values: Vec<String>,
     /// The _meta property is reserved by ACP to allow clients and agents to attach additional
@@ -598,7 +604,8 @@ impl StringMultiSelectItems {
 #[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize, JsonSchema)]
 #[non_exhaustive]
 pub struct TitledMultiSelectItems {
-    /// Titled enum options.
+    /// Titled enum options. Must contain at least one option.
+    #[schemars(length(min = 1))]
     #[serde(rename = "anyOf")]
     pub options: Vec<EnumOption>,
     /// The _meta property is reserved by ACP to allow clients and agents to attach additional
@@ -1667,7 +1674,7 @@ pub struct ElicitationUrlMode {
     /// The unique identifier for this elicitation.
     pub elicitation_id: ElicitationId,
     /// The URL to direct the user to.
-    #[schemars(extend("format" = "uri"))]
+    #[schemars(url)]
     pub url: String,
 }
 

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

@@ -1028,6 +1028,7 @@ pub struct DidOpenDocumentNotification {
     /// The session ID for this notification.
     pub session_id: SessionId,
     /// The URI of the opened document.
+    #[schemars(url)]
     pub uri: String,
     /// The language identifier of the document (e.g., "rust", "python").
     pub language_id: String,
@@ -1090,6 +1091,7 @@ pub struct DidChangeDocumentNotification {
     /// The session ID for this notification.
     pub session_id: SessionId,
     /// The URI of the changed document.
+    #[schemars(url)]
     pub uri: String,
     /// The new version number of the document.
     pub version: i64,
@@ -1210,6 +1212,7 @@ pub struct DidCloseDocumentNotification {
     /// The session ID for this notification.
     pub session_id: SessionId,
     /// The URI of the closed document.
+    #[schemars(url)]
     pub uri: String,
     /// The _meta property is reserved by ACP to allow clients and agents to attach additional
     /// metadata to their interactions. Implementations MUST NOT make assumptions about values at
@@ -1257,6 +1260,7 @@ pub struct DidSaveDocumentNotification {
     /// The session ID for this notification.
     pub session_id: SessionId,
     /// The URI of the saved document.
+    #[schemars(url)]
     pub uri: String,
     /// The _meta property is reserved by ACP to allow clients and agents to attach additional
     /// metadata to their interactions. Implementations MUST NOT make assumptions about values at
@@ -1304,6 +1308,7 @@ pub struct DidFocusDocumentNotification {
     /// The session ID for this notification.
     pub session_id: SessionId,
     /// The URI of the focused document.
+    #[schemars(url)]
     pub uri: String,
     /// The version number of the document.
     pub version: i64,
@@ -1368,6 +1373,7 @@ pub struct StartNesRequest {
     /// The root URI of the workspace.
     #[serde_as(deserialize_as = "DefaultOnError")]
     #[schemars(extend("x-deserialize-default-on-error" = true))]
+    #[schemars(url)]
     #[serde(default)]
     pub workspace_uri: Option<String>,
     /// The workspace folders.
@@ -1452,6 +1458,7 @@ impl Default for StartNesRequest {
 #[non_exhaustive]
 pub struct WorkspaceFolder {
     /// The URI of the folder.
+    #[schemars(url)]
     pub uri: String,
     /// The display name of the folder.
     pub name: String,
@@ -1710,6 +1717,7 @@ pub struct SuggestNesRequest {
     /// The session ID for this request.
     pub session_id: SessionId,
     /// The URI of the document to suggest for.
+    #[schemars(url)]
     pub uri: String,
     /// The version number of the document.
     pub version: i64,
@@ -1892,6 +1900,7 @@ impl NesSuggestContext {
 #[non_exhaustive]
 pub struct NesRecentFile {
     /// The URI of the file.
+    #[schemars(url)]
     pub uri: String,
     /// The language identifier.
     pub language_id: String,
@@ -1945,6 +1954,7 @@ impl NesRecentFile {
 #[non_exhaustive]
 pub struct NesRelatedSnippet {
     /// The URI of the file containing the snippets.
+    #[schemars(url)]
     pub uri: String,
     /// The code excerpts.
     pub excerpts: Vec<NesExcerpt>,
@@ -2040,6 +2050,7 @@ impl NesExcerpt {
 #[non_exhaustive]
 pub struct NesEditHistoryEntry {
     /// The URI of the edited file.
+    #[schemars(url)]
     pub uri: String,
     /// A diff representing the edit.
     pub diff: String,
@@ -2088,6 +2099,7 @@ pub struct NesUserAction {
     /// The kind of action (e.g., "insertChar", "cursorMovement").
     pub action: String,
     /// The URI of the file where the action occurred.
+    #[schemars(url)]
     pub uri: String,
     /// The position where the action occurred.
     pub position: Position,
@@ -2143,6 +2155,7 @@ impl NesUserAction {
 #[non_exhaustive]
 pub struct NesOpenFile {
     /// The URI of the file.
+    #[schemars(url)]
     pub uri: String,
     /// The language identifier.
     pub language_id: String,
@@ -2215,6 +2228,7 @@ impl NesOpenFile {
 #[non_exhaustive]
 pub struct NesDiagnostic {
     /// The URI of the file containing the diagnostic.
+    #[schemars(url)]
     pub uri: String,
     /// The range of the diagnostic.
     pub range: Range,
@@ -2455,8 +2469,10 @@ pub struct NesEditSuggestion {
     /// Unique identifier for accept/reject tracking.
     pub suggestion_id: NesSuggestionId,
     /// The URI of the file to edit.
+    #[schemars(url)]
     pub uri: String,
-    /// The text edits to apply.
+    /// The text edits to apply. Must contain at least one edit.
+    #[schemars(length(min = 1))]
     pub edits: Vec<NesTextEdit>,
     /// Optional suggested cursor position after applying edits.
     #[serde_as(deserialize_as = "DefaultOnError")]
@@ -2567,6 +2583,7 @@ pub struct NesJumpSuggestion {
     /// Unique identifier for accept/reject tracking.
     pub suggestion_id: NesSuggestionId,
     /// The file to navigate to.
+    #[schemars(url)]
     pub uri: String,
     /// The target position within the file.
     pub position: Position,
@@ -2620,6 +2637,7 @@ pub struct NesRenameSuggestion {
     /// Unique identifier for accept/reject tracking.
     pub suggestion_id: NesSuggestionId,
     /// The file URI containing the symbol.
+    #[schemars(url)]
     pub uri: String,
     /// The position of the symbol to rename.
     pub position: Position,
@@ -2677,6 +2695,7 @@ pub struct NesSearchAndReplaceSuggestion {
     /// Unique identifier for accept/reject tracking.
     pub suggestion_id: NesSuggestionId,
     /// The file URI to search within.
+    #[schemars(url)]
     pub uri: String,
     /// The text or pattern to find.
     pub search: String,

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

@@ -280,6 +280,7 @@ pub struct PlanFile {
     /// The plan ID to update.
     pub plan_id: PlanId,
     /// The URI of the file containing the plan.
+    #[schemars(url)]
     pub uri: String,
     /// The _meta property is reserved by ACP to allow clients and agents to attach additional
     /// metadata to their interactions. Implementations MUST NOT make assumptions about values at