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retoor 251c3dc2ba research: mcp-client-support subject (106 sources, 3 conclusions)

- wire spec: lifecycle, stdio + Streamable HTTP transports, tools,
  utilities, legacy SSE, versioning, changelog (14 Tier 1)
- client ecosystem: Claude Code/VS Code/Cursor/Codex configs,
  mcp-remote, Smithery, registries, Glama (12 Tier 1)
- security/ops: authorization draft, trust model, poisoning,
  rug pulls, production hardening (12 Tier 1) + 68 Tier 2 cards
- conclusions: minimal stdlib client on 2025-11-25, normalizer +
  resolver agent for pasted configs/GitHub URLs, untrusted-until-
  consent trust model; nothing built yet
- audit PASS (14 subjects, 797 sources, 32 conclusions)

2026-10-18 19:23:02 +02:00

3.4 KiB

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Sampling (client feature, 2025-11-25)

Metadata

Field	Value
Institute	Molodetz Institute - Research & Retrieval Division
Subject	mcp-client-support
Document type	Source Dossier
Tier	1
Source title	Sampling (MCP Specification v2025-11-25)
Source URL	https://modelcontextprotocol.io/specification/2025-11-25/client/sampling
Source publisher / author	Model Context Protocol authors (Anthropic-donated open project; site docs)
Source type	standard
Source date (published)	2025-11-25 (version stamp; no other publish date stated)
Date researched	2026-10-18
Researched by	tai (agent), model: Claude Sonnet 5, on behalf of retoor
Research method	gather-subagent direct page fetch, parent synthesis from evidence pack
Confidence	High (partial read; findings cover retrieved sections only, see Cons)
Status	Active

Summary

Sampling lets servers request LLM completions through the client ("with no server API keys necessary") via the server-to-client sampling/createMessage request carrying messages, model preferences, system prompt, and max tokens. Clients must declare the sampling capability (plus sampling.tools for tool-using requests, which servers must not send otherwise). The includeContext values thisServer/allServers are soft-deprecated and servers should avoid them.

Key findings

Sampling is servers requesting "LLM sampling ('completions' or 'generations')… via clients… with no server API keys necessary."
"Clients that support sampling MUST declare the sampling capability"; tool use in sampling needs sampling.tools, and "Servers MUST NOT send tool-enabled sampling requests to Clients that have not declared" it.
Server-to-client request sampling/createMessage with messages[], modelPreferences, systemPrompt, maxTokens; the client responds with role/content/model/stopReason.
includeContext values "thisServer"/"allServers" are "soft-deprecated"; "Servers SHOULD avoid using these values."

Pros / strengths

Sensible trust design: the client holds the keys and the model policy, and the sampling.tools sub-capability gates the riskiest (tool-using) requests so servers cannot escalate unilaterally.
Request/response shapes are explicit (messages, preferences, system prompt, max tokens in; role, content, model, stop reason out).
Soft-deprecation of the broad includeContext values shows the spec actively narrowing context leakage.

Cons / limitations / caveats

Per the pack's Uncertainty notes this page was only partially read; the sampling-with-tools flow and deeper subsections were not read, so findings cover the retrieved sections only.
No explicit author names or publish dates appear on the page; the date above is the version stamp in the URL.
Deprecated in the 2026-07-28 revision along with roots and logging, and server-initiated requests are replaced by MRTR there; also, sampling needs a real LLM backend, which is far outside a minimal stdlib client's scope.

Relevance to tai

Optional and LLM-backed, so safely omitted by a minimal client (no declared capability, -32601 if asked). Notable for tai only as a future direction: a client with model access could one day offer sampling, but the deprecation in 2026-07-28 argues against investing here.

Changelog

Date	Change
2026-10-18	Initial dossier created.

3.4 KiB Raw Blame History