chore(spec): Update A2A types from specification 🤖 (#350)

This PR updates `src/a2a/types.py` based on the latest
`specification/json/a2a.json` from
[a2aproject/A2A](a2aproject/A2A@ef4a305).

Author: a2a-bot

.github/actions/spelling/allow.txt

@@ -45,6 +45,7 @@ INR
 isready
 JPY
 JSONRPCt
+JWS
 kwarg
 langgraph
 lifecycles

src/a2a/grpc/a2a_pb2.py

@@ -202,7 +202,7 @@ class AgentInterface(_message.Message):
     def __init__(self, url: _Optional[str] = ..., transport: _Optional[str] = ...) -> None: ...
 
 class AgentCard(_message.Message):
-    __slots__ = ("protocol_version", "name", "description", "url", "preferred_transport", "additional_interfaces", "provider", "version", "documentation_url", "capabilities", "security_schemes", "security", "default_input_modes", "default_output_modes", "skills", "supports_authenticated_extended_card")
+    __slots__ = ("protocol_version", "name", "description", "url", "preferred_transport", "additional_interfaces", "provider", "version", "documentation_url", "capabilities", "security_schemes", "security", "default_input_modes", "default_output_modes", "skills", "supports_authenticated_extended_card", "signatures")
     class SecuritySchemesEntry(_message.Message):
         __slots__ = ("key", "value")
         KEY_FIELD_NUMBER: _ClassVar[int]
@@ -226,6 +226,7 @@ class AgentCard(_message.Message):
     DEFAULT_OUTPUT_MODES_FIELD_NUMBER: _ClassVar[int]
     SKILLS_FIELD_NUMBER: _ClassVar[int]
     SUPPORTS_AUTHENTICATED_EXTENDED_CARD_FIELD_NUMBER: _ClassVar[int]
+    SIGNATURES_FIELD_NUMBER: _ClassVar[int]
     protocol_version: str
     name: str
     description: str
@@ -242,7 +243,8 @@ class AgentCard(_message.Message):
     default_output_modes: _containers.RepeatedScalarFieldContainer[str]
     skills: _containers.RepeatedCompositeFieldContainer[AgentSkill]
     supports_authenticated_extended_card: bool
-    def __init__(self, protocol_version: _Optional[str] = ..., name: _Optional[str] = ..., description: _Optional[str] = ..., url: _Optional[str] = ..., preferred_transport: _Optional[str] = ..., additional_interfaces: _Optional[_Iterable[_Union[AgentInterface, _Mapping]]] = ..., provider: _Optional[_Union[AgentProvider, _Mapping]] = ..., version: _Optional[str] = ..., documentation_url: _Optional[str] = ..., capabilities: _Optional[_Union[AgentCapabilities, _Mapping]] = ..., security_schemes: _Optional[_Mapping[str, SecurityScheme]] = ..., security: _Optional[_Iterable[_Union[Security, _Mapping]]] = ..., default_input_modes: _Optional[_Iterable[str]] = ..., default_output_modes: _Optional[_Iterable[str]] = ..., skills: _Optional[_Iterable[_Union[AgentSkill, _Mapping]]] = ..., supports_authenticated_extended_card: bool = ...) -> None: ...
+    signatures: _containers.RepeatedCompositeFieldContainer[AgentCardSignature]
+    def __init__(self, protocol_version: _Optional[str] = ..., name: _Optional[str] = ..., description: _Optional[str] = ..., url: _Optional[str] = ..., preferred_transport: _Optional[str] = ..., additional_interfaces: _Optional[_Iterable[_Union[AgentInterface, _Mapping]]] = ..., provider: _Optional[_Union[AgentProvider, _Mapping]] = ..., version: _Optional[str] = ..., documentation_url: _Optional[str] = ..., capabilities: _Optional[_Union[AgentCapabilities, _Mapping]] = ..., security_schemes: _Optional[_Mapping[str, SecurityScheme]] = ..., security: _Optional[_Iterable[_Union[Security, _Mapping]]] = ..., default_input_modes: _Optional[_Iterable[str]] = ..., default_output_modes: _Optional[_Iterable[str]] = ..., skills: _Optional[_Iterable[_Union[AgentSkill, _Mapping]]] = ..., supports_authenticated_extended_card: bool = ..., signatures: _Optional[_Iterable[_Union[AgentCardSignature, _Mapping]]] = ...) -> None: ...
 
 class AgentProvider(_message.Message):
     __slots__ = ("url", "organization")
@@ -292,6 +294,16 @@ class AgentSkill(_message.Message):
     output_modes: _containers.RepeatedScalarFieldContainer[str]
     def __init__(self, id: _Optional[str] = ..., name: _Optional[str] = ..., description: _Optional[str] = ..., tags: _Optional[_Iterable[str]] = ..., examples: _Optional[_Iterable[str]] = ..., input_modes: _Optional[_Iterable[str]] = ..., output_modes: _Optional[_Iterable[str]] = ...) -> None: ...
 
+class AgentCardSignature(_message.Message):
+    __slots__ = ("protected", "signature", "header")
+    PROTECTED_FIELD_NUMBER: _ClassVar[int]
+    SIGNATURE_FIELD_NUMBER: _ClassVar[int]
+    HEADER_FIELD_NUMBER: _ClassVar[int]
+    protected: str
+    signature: str
+    header: _struct_pb2.Struct
+    def __init__(self, protected: _Optional[str] = ..., signature: _Optional[str] = ..., header: _Optional[_Union[_struct_pb2.Struct, _Mapping]] = ...) -> None: ...
+
 class TaskPushNotificationConfig(_message.Message):
     __slots__ = ("name", "push_notification_config")
     NAME_FIELD_NUMBER: _ClassVar[int]

src/a2a/grpc/a2a_pb2.pyi

@@ -48,6 +48,27 @@ class APIKeySecurityScheme(A2ABaseModel):
     """
 
 
+class AgentCardSignature(A2ABaseModel):
+    """
+    AgentCardSignature represents a JWS signature of an AgentCard.
+    This follows the JSON format of an RFC 7515 JSON Web Signature (JWS).
+    """
+
+    header: dict[str, Any] | None = None
+    """
+    The unprotected JWS header values.
+    """
+    protected: str
+    """
+    The protected JWS header for the signature. This is a Base64url-encoded
+    JSON object, as per RFC 7515.
+    """
+    signature: str
+    """
+    The computed signature, Base64url-encoded.
+    """
+
+
 class AgentExtension(A2ABaseModel):
     """
     A declaration of a protocol extension supported by an Agent.
@@ -1705,6 +1726,10 @@ class AgentCard(A2ABaseModel):
     A declaration of the security schemes available to authorize requests. The key is the
     scheme name. Follows the OpenAPI 3.0 Security Scheme Object.
     """
+    signatures: list[AgentCardSignature] | None = None
+    """
+    JSON Web Signatures computed for this AgentCard.
+    """
     skills: list[AgentSkill]
     """
     The set of skills, or distinct capabilities, that the agent can perform.