88831b46f6
Move the documentation that had grown to 3000+ lines in README.md onto https://ruby.sdk.modelcontextprotocol.io and slim the README down to a quick start and feature overview, following the Python SDK layout: - Add 21 server pages as the docs/_server/ collection (overview plus transports, discovery, tools, prompts, resources, roots, sampling, elicitation, multi round-trip results, notifications, notification subscriptions, cancellation, progress, ping, completions, logging, pagination, server context, configuration, and custom methods), 8 client pages as the docs/_client/ collection (overview, transports, lifecycle, multi round-trip results, cancellation, ping, pagination, and authorization), and 3 extension pages as the docs/_extensions/ collection (overview, capability extensions, and MCP Apps, following the Extensions Overview recommendation that SDK documentation list the supported extensions) - one page per topic, ordered to match the sidebar of the 2026-07-28 specification, with the client-side APIs (pinging, cancelling, and paginating from MCP::Client) documented under Building Clients - Add top-level Examples and Protocol Versions pages after Installation, linking the runnable examples in examples/ and summarizing the supported protocol versions, the era model, and client negotiation - Render the three sections as just-the-docs collections, which list every page beneath a plain category heading in the sidebar with no folding, and serve every page at an extensionless URL under /server/, /client/, and /extensions/, matching the sibling SDK documentation sites - Replace docs/building-servers.md and docs/building-clients.md with redirects to the new section overview pages via jekyll-redirect-from, redirect the previously published /installation.html to its extensionless URL, fold their content that was missing from README.md into the new pages, and update the Tool argument keys reference comment in lib/mcp/server.rb to the relocated Tools page - Reduce README.md to the badges, a compact feature overview in the Python SDK style, installation instructions, a stdio server and client quick start, and a License section, using absolute URLs for the remaining repository links so they resolve on rubygems.org - Adapt formatting where GitHub rendering habits break on the site: convert the numbered "three ways to define" lists into headings, since kramdown restarts numbering at 1 when code blocks split list items, convert GitHub-style alerts into just-the-docs callouts with the SEP-2260 server-to-client association note raised to a red warning, merge the duplicated Exception Reporting and Configuration Block Data sections into the Configuration page, and relocate the Streamable HTTP settings that were nested under the Logging section into the Transports page - Refresh the migrated content against the current implementation: correct stale claims and broken samples the README carried, note on each session-era feature how it relates to the modern lifecycle of MCP 2026-07-28, and point spec links at the latest revision, keeping deliberate 2025-11-25 pins for pages the modern revision removed - Style the site after the Rails API documentation palette (red links and accents on neutral surfaces) with matching light and dark color schemes, center the sidebar and content as one block, add a Previous/Next footer pager following the sidebar order, open external links in a new tab, and serve the MCP logo as the favicon Every code block and heading from the previous README was verified to have a home in the new docs pages or the slimmed README before the reduction; a few samples were corrected rather than copied, as noted above.
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| layout | title | nav_order |
|---|---|---|
| default | Pagination | 18 |
Pagination
The MCP Ruby SDK supports pagination
for list operations that may return large result sets. Pagination uses string cursor tokens carrying a zero-based offset,
treated as opaque by clients: the server decides page size, and the client follows nextCursor until the server omits it.
Pagination applies to tools/list, prompts/list, resources/list, and resources/templates/list,
including lists produced by a custom resources_list_handler.
Enabling Pagination
Pass page_size: to MCP::Server.new to split list responses into pages. When page_size is omitted (the default),
list responses contain all items in a single response, preserving the pre-pagination behavior.
server = MCP::Server.new(
name: "my_server",
tools: tools,
page_size: 50,
)
When page_size is set, list responses include a nextCursor field whenever more pages are available:
{
"jsonrpc": "2.0",
"id": 1,
"result": {
"tools": [
{ "name": "example_tool" }
],
"nextCursor": "50"
}
}
Invalid cursors (e.g. non-numeric, negative, or out-of-range) are rejected with JSON-RPC error code -32602 (Invalid params) per the MCP specification.
List Result Caching
Per SEP-2549, list and read results can carry cache hints telling clients how long a result stays fresh (ttlMs, max-age semantics in milliseconds;
0 means do not cache) and whether shared intermediaries may cache it (cacheScope: "public" or "private").
Emission is opt-in: pass ttl_ms: and/or cache_scope: to MCP::Server.new and both fields are added to tools/list, prompts/list, resources/list,
resources/templates/list, and resources/read results (a missing field is filled with the defaults ttlMs: 0 / cacheScope: "private",
the scope that keeps a potentially user-dependent result out of shared caches).
When neither is set, responses are serialized exactly as before.
The 2026-07-28 revision makes both hints required on these results, so on requests carrying the modern _meta envelope
the server always emits them, filling unset values with the same defaults; legacy protocol versions keep the opt-in behavior.
server = MCP::Server.new(
name: "my_server",
tools: tools,
ttl_ms: 60_000, # results stay fresh for one minute
cache_scope: "private", # only the requesting client may cache them
)
A resources_read_handler can override the hints per result by returning a full result hash instead of bare contents:
server.resources_read_handler do |params|
{ contents: [{ uri: params[:uri], mimeType: "text/plain", text: "..." }], ttlMs: 5_000 }
end
Client Side
Iterating pages, fetching whole collections with the max_pages guard, and reading the cache hints
on the result structs are documented on the client Pagination page.