Struct AgentCard 

pub struct AgentCard {

    pub name: String,
    pub url: Option<String>,
    pub description: String,
    pub version: String,
    pub supported_interfaces: Vec<AgentInterface>,
    pub default_input_modes: Vec<String>,
    pub default_output_modes: Vec<String>,
    pub skills: Vec<AgentSkill>,
    pub capabilities: AgentCapabilities,
    pub provider: Option<AgentProvider>,
    pub icon_url: Option<String>,
    pub documentation_url: Option<String>,
    pub security_schemes: Option<HashMap<String, SecurityScheme>>,
    pub security_requirements: Option<Vec<SecurityRequirement>>,
    pub signatures: Option<Vec<AgentCardSignature>>,
}

The root discovery document for an A2A agent.

Served at /.well-known/agent-card.json. Clients fetch this document to discover the agent’s interfaces, capabilities, skills, and security requirements before establishing a session.

In v1.0, protocol_version and url moved to AgentInterface, and supported_interfaces replaces the old url/preferred_transport/ additional_interfaces fields.

Fields

name: String

Display name of the agent.

url: Option<String>

Primary URL of the agent — accepted on input, never emitted.

This is the v0.3 top-level URL. The v1.0 lf.a2a.v1 AgentCard has no url field at all; supported_interfaces replaced it. Emitting it made this SDK’s card fail the specification’s own JSON schema — 'url' does not match any of the regexes: … — which is what CARD-EXT-001 reports (see docs/official-tck-findings.md §13).

It is still parsed, because a card published by a v0.3 peer carries it and dropping the field would fail those cards outright. The reference implementation does the same, popping url and folding it into supportedInterfaces.

Read it if you have it; to publish an agent’s address, use supported_interfaces.

description: String

Human-readable description of the agent’s purpose.

version: String

Semantic version of this agent implementation.

supported_interfaces: Vec<AgentInterface>

Transport interfaces offered by this agent.

Spec requirement: Must contain at least one element — enforced by validate, not at parse time: ProtoJSON printers omit empty repeated fields, so parsing treats absence as empty and validation reports the real problem instead of a JSON type error.

default_input_modes: Vec<String>

Default MIME types accepted as input.

ProtoJSON printers omit empty repeated fields; absence means empty.

default_output_modes: Vec<String>

Default MIME types produced as output.

ProtoJSON printers omit empty repeated fields; absence means empty.

skills: Vec<AgentSkill>

Skills offered by this agent.

Spec requirement: Must contain at least one element. Parsing treats absence as empty (ProtoJSON omits empty repeated fields).

capabilities: AgentCapabilities

Capability flags.

provider: Option<AgentProvider>

The organization operating this agent.

icon_url: Option<String>

URL of the agent’s icon image.

documentation_url: Option<String>

URL of the agent’s documentation.

security_schemes: Option<HashMap<String, SecurityScheme>>

Named security scheme definitions (OpenAPI-style).

security_requirements: Option<Vec<SecurityRequirement>>

Global security requirements for the agent.

signatures: Option<Vec<AgentCardSignature>>

Cryptographic signatures over this card.

Implementations

impl AgentCard

pub const fn validate(&self) -> Result<(), &'static str>

Validates the agent card for completeness.

Errors

Returns an error if:

• name is empty
• supported_interfaces is empty (spec requires at least one interface)

Trait Implementations

impl Clone for AgentCard

fn clone(&self) -> AgentCard

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for AgentCard

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for AgentCard

fn deserialize<__D>( __deserializer: __D, ) -> Result<AgentCard, <__D as Deserializer<'de>>::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Serialize for AgentCard

fn serialize<__S>( &self, __serializer: __S, ) -> Result<<__S as Serializer>::Ok, <__S as Serializer>::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl TryFrom<AgentCard> for AgentCard

type Error = ConvertError

The type returned in the event of a conversion error.

fn try_from( value: AgentCard, ) -> Result<AgentCard, <AgentCard as TryFrom<AgentCard>>::Error>

Performs the conversion.

impl TryFrom<AgentCard> for AgentCard

type Error = ConvertError

The type returned in the event of a conversion error.

fn try_from( value: AgentCard, ) -> Result<AgentCard, <AgentCard as TryFrom<AgentCard>>::Error>

Performs the conversion.