Struct ExtendedAgentCard 

pub struct ExtendedAgentCard {
    pub public: AgentCard,
}

The card an authenticated peer may fetch: the same agent, in more detail.

A2A’s GetExtendedAgentCard exists because the public card is read by anyone, and some of what a peer legitimately wants to know is not for everyone: which tools an agent may reach, what it is allowed to spend, and what part it plays in a larger arrangement.

Why this is a separate type

Serving the wrong card is a one-line mistake with no symptom — the response is valid JSON either way, and the extra fields simply appear on a public endpoint where nobody notices until somebody reads them. A distinct type makes that a compile error instead: a handler for the public path cannot return this, because it is not an AgentCard.

What it still will not say

Not the model, and not the protected-field rules. Which model an agent runs on is a fact about a supply chain, and the exact fields a sink guards is a map of where to push — both are disclosure that helps an attacker more than a caller. The tool names are here because a peer deciding whether to delegate genuinely needs to know what the far side can reach.

Where the extra detail lives

In the EXT_GOVERNANCE extension under capabilities.extensions — the spec’s own slot for what its schema does not name — rather than as top-level fields, which the official conformance kit rejects outright. Injected at derive time, not at serialization, so a signature taken over the card covers the disclosure: an extension added after signing would be exactly the unverifiable claim the signature exists to prevent.

Fields

public: AgentCard

The card, with the governance extension included.

Implementations

impl ExtendedAgentCard

pub fn derive( manifest: &Manifest, url: impl Into<String>, ) -> Result<Self, ManifestError>

Derive the authenticated card.

Errors

If the manifest’s digest cannot be computed.

pub fn tools(&self) -> Vec<ExtendedTool>

The tools the governance extension discloses.

pub fn budget(&self) -> Option<ExtendedBudget>

The per-run budget the governance extension discloses, when one is.

pub fn topology(&self) -> Option<String>

The declared topology, when one is.

Trait Implementations

impl Clone for ExtendedAgentCard

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for ExtendedAgentCard

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for ExtendedAgentCard

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Eq for ExtendedAgentCard

impl PartialEq for ExtendedAgentCard

fn eq(&self, other: &Self) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl Serialize for ExtendedAgentCard

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

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl StructuralPartialEq for ExtendedAgentCard