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feat: add modern client lifecycle modes (SEP-2575) (#995)

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* feat: add modern client lifecycle modes

* refactor: drop modern naming and dead cleanup

* fix: gate request metadata on inline lifecycle only
This commit is contained in:
Dale Seo 2026-07-16 17:12:16 -04:00 • committed by GitHub
commit 2e2c79173c
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1 changed files with 1525 additions and 306 deletions
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38
crates/rmcp/src/handler/server.rs
View file

@ -41,22 +41,30 @@ impl<H: ServerHandler> Service<RoleServer> for H {
));
}
}
if matches!(&request, ClientRequest::DiscoverRequest(_)) {
if requested_version.is_none() {
// Self-contained metadata is required only when the request itself uses
// the inline lifecycle: a discover opener, a session that started without
// `initialize`, or a request that declares 2026-07-28+ in its own _meta.
// Sessions that negotiated via `initialize` (or `serve_directly`) keep the
// session model and may omit per-request metadata.
let requires_request_metadata = uses_inline_negotiation
&& (matches!(&request, ClientRequest::DiscoverRequest(_))
|| context.peer.request_metadata_required()
|| requested_version.as_ref().is_some_and(|version| {
version.as_str() >= ProtocolVersion::V_2026_07_28.as_str()
}));
if requires_request_metadata {
// Inline lifecycle requests are defined by the 2026-07-28 protocol.
// Validate that lifecycle contract even when a request selects an
// older application protocol version.
let missing = context
.meta
.missing_required_keys(&ProtocolVersion::V_2026_07_28);
if !missing.is_empty() {
return Err(McpError::invalid_params(
"server/discover requires protocolVersion in request _meta",
None,
));
}
if context.meta.client_info().is_none() {
return Err(McpError::invalid_params(
"server/discover requires clientInfo in request _meta",
None,
));
}
if context.meta.client_capabilities().is_none() {
return Err(McpError::invalid_params(
"server/discover requires clientCapabilities in request _meta",
format!(
"request _meta is missing or has malformed required fields: {}",
missing.join(", ")
),
None,
));
}