Struct ClientCapabilities 

pub struct ClientCapabilities {
    pub elicitation: Option<ClientCapabilitiesElicitation>,
    pub experimental: Option<BTreeMap<String, Map<String, Value>>>,
    pub extensions: Option<BTreeMap<String, Map<String, Value>>>,
    pub roots: Option<ClientCapabilitiesRoots>,
    pub sampling: Option<ClientCapabilitiesSampling>,
}

Capabilities a client may support. Known capabilities are defined here, in this schema, but this is not a closed set: any client can define its own, additional capabilities.

Fields

elicitation: Option<ClientCapabilitiesElicitation>

Present if the client supports elicitation from the server.

experimental: Option<BTreeMap<String, Map<String, Value>>>

Experimental, non-standard capabilities that the client supports.

extensions: Option<BTreeMap<String, Map<String, Value>>>

Optional MCP extensions that the client supports. Keys are extension identifiers (e.g., “io.modelcontextprotocol/oauth-client-credentials”), and values are per-extension settings objects. An empty object indicates support with no settings.

Keys MUST follow the MetaObject_meta``, with a mandatory prefix.

roots: Option<ClientCapabilitiesRoots>

👎Deprecated:

Deprecated as of protocol version 2026-07-28 (SEP-2577). Remains in the specification for at least twelve months; see the deprecated features registry.

Present if the client supports listing roots.

sampling: Option<ClientCapabilitiesSampling>

👎Deprecated:

Deprecated as of protocol version 2026-07-28 (SEP-2577). Remains in the specification for at least twelve months; see the deprecated features registry.

Present if the client supports sampling from an LLM.

Trait Implementations

impl Clone for ClientCapabilities

fn clone(&self) -> ClientCapabilities

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for ClientCapabilities

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

Formats the value using the given formatter.

impl Default for ClientCapabilities

fn default() -> ClientCapabilities

Returns the “default value” for a type.

impl<'de> Deserialize<'de> for ClientCapabilities

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

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl PartialEq for ClientCapabilities

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

Equality operator ==.

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

Inequality operator !=.

impl Serialize for ClientCapabilities

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 StructuralPartialEq for ClientCapabilities