Which side is obliged to support discovery, and which side may skip it?

Easymcpdiscoveryversioningcapabilities

Last reviewed 22 Aug 2026

Neither may skip it, because it is discovery that establishes the version every later request will use.
Servers must implement it; clients may call it or may go straight to the request they wanted.Correct answer
Clients must call it before anything else, and servers may implement it if they find it useful to.
Both may skip it, since either side can fall back to trying a request and reading whatever comes back.

Show answer & explanation

Correct answer: B. Servers must implement it; clients may call it or may go straight to the request they wanted.

Explanation

The principle — An obligation on one side and a convenience on the other is a deliberate asymmetry, not an inconsistency.

Why the key is correct — Servers MUST implement server/discover. On the other side: calling server/discover is optional for clients — a client may invoke any RPC inline and handle UnsupportedProtocolVersionError if the server does not support the requested version.

Why the others are wrong — Clients are not required to call first, servers are not free to omit it, and it does not replace the per-request version declaration.

Remember this — Every server answers it; no client has to ask.

Sources — MCP first-party documentation.

Sources

Primary sourceVersioning and Compatibility — MCP · accessed 20 Aug 2026
“Servers MUST implement server/discover.”
Primary sourceDiscovery — MCP · accessed 20 Aug 2026
“Calling server/discover is optional for clients — a client may invoke any RPC inline and handle UnsupportedProtocolVersionError if the server does not support the requested version.”

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Which side is obliged to support discovery, and which side may skip it?

Easymcpdiscoveryversioningcapabilities

Last reviewed 22 Aug 2026

Neither may skip it, because it is discovery that establishes the version every later request will use.
Servers must implement it; clients may call it or may go straight to the request they wanted.Correct answer
Clients must call it before anything else, and servers may implement it if they find it useful to.
Both may skip it, since either side can fall back to trying a request and reading whatever comes back.

Show answer & explanation

Correct answer: B. Servers must implement it; clients may call it or may go straight to the request they wanted.

Explanation

The principle — An obligation on one side and a convenience on the other is a deliberate asymmetry, not an inconsistency.

Why the others are wrong — Clients are not required to call first, servers are not free to omit it, and it does not replace the per-request version declaration.

Remember this — Every server answers it; no client has to ask.

Sources — MCP first-party documentation.

Sources

Primary sourceVersioning and Compatibility — MCP · accessed 20 Aug 2026
“Servers MUST implement server/discover.”
Primary sourceDiscovery — MCP · accessed 20 Aug 2026
“Calling server/discover is optional for clients — a client may invoke any RPC inline and handle UnsupportedProtocolVersionError if the server does not support the requested version.”

Practise 10 questions on this topic

Take MCP Fundamentals — Timed Test 1 (10 questions) — scored instantly, explanation for every question, no login.

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Which side is obliged to support discovery, and which side may skip it?

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Which side is obliged to support discovery, and which side may skip it?

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