c9d36b04bf
Three pages carried names the 2026-07-28 specification does not use: "Multi-Round-Trip Results" for the pattern the specification titles Multi Round-Trip Requests (MRTR) and serves at basic/patterns/mrtr - the results are the `InputRequiredResult` wire type, not the feature - plus "Completions" for the utility the specification titles Completion, and "Notification Subscriptions" for the pattern it titles Subscriptions. Retitle the three pages to the specification's names, move them to /server/mrtr/ and /client/mrtr/, /server/completion/, and /server/subscriptions/ following the specification's slugs, update every internal reference, and keep the URLs published with v1.3.0 working via jekyll-redirect-from. The Discovery page keeps its title but moves from /server/discovery/ to /server/discover/, matching the specification's slug and the `server/discover` RPC, with its published URL redirected the same way.
46 lines
2.3 KiB
Markdown
46 lines
2.3 KiB
Markdown
---
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layout: default
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title: Overview
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nav_order: 1
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permalink: /client/
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redirect_from:
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- /building-clients.html
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- /building-clients/
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---
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# Building an MCP Client
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The `MCP::Client` class provides an interface for interacting with MCP servers.
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This class supports:
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- Lifecycle negotiation and connection via `MCP::Client#connect`, adopting the modern lifecycle
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when the server serves it; see [Lifecycle](/client/lifecycle/)
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- Server discovery via the `server/discover` method (`MCP::Client#discover`); see [Explicit Discovery](/client/lifecycle/#explicit-discovery)
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- Liveness check via the `ping` method (`MCP::Client#ping`)
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- Tool listing via the `tools/list` method (`MCP::Client#tools`)
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- Tool invocation via the `tools/call` method (`MCP::Client#call_tool`)
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- Resource listing via the `resources/list` method (`MCP::Client#resources`)
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- Resource template listing via the `resources/templates/list` method (`MCP::Client#resource_templates`)
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- Resource reading via the `resources/read` method (`MCP::Client#read_resource`)
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- Prompt listing via the `prompts/list` method (`MCP::Client#prompts`)
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- Prompt retrieval via the `prompts/get` method (`MCP::Client#get_prompt`)
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- Completion requests via the `completion/complete` method (`MCP::Client#complete`); see [Completion](/server/completion/)
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- Automatic driving of multi round-trip `input_required` results once `on_elicitation`, `on_sampling`,
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or `on_roots` handlers are registered; see [Multi Round-Trip Requests](/client/mrtr/)
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- Cancellation of in-flight requests via the `cancellation:` keyword; see [Cancellation](/client/cancellation/)
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- Cursor-based page iteration on the `list_*` methods and whole-collection fetching with
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the `max_pages` guard; see [Pagination](/client/pagination/)
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- Automatic JSON-RPC 2.0 message formatting
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- UUID request ID generation
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Clients are initialized with a [transport layer](/client/transports/) instance that handles the low-level communication mechanics.
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Authorization is handled by the transport layer; see [Authorization](/client/authorization/).
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## Tool Objects
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The client provides a wrapper class for tools returned by the server:
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- `MCP::Client::Tool` - Represents a single tool with its metadata
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This class provides easy access to tool properties like name, description, input schema, and output schema.
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