protocol

mcp_cache_protocol

Optional protocol for per-operation cache policy used by the MCP 2026-07-28 specification. An application may implement cache_policy/4 to choose TTL (milliseconds) and scope (public or private) for complete results of server/discover, list operations (tools/list, prompts/list, resources/list, resources/templates/list), and resources/read. Cache fields are never attached to input_required results or MRTR retries. When the predicate is not defined, or for an operation it does not cover, the server falls back to the options cache_ttl(0) and cache_scope(private).

Availability:

logtalk_load(mcp_server(loader))

Author: Paulo Moura

Version: 1:0:0

Date: 2026-08-14

Compilation flags:

static

Dependencies:

(none)

Remarks:

• TTL: A non-negative integer number of milliseconds. 0 means the result must not be cached.

• Scope: Either public (may be shared across clients) or private (client-specific).

• Applicability: Only complete final results of discover, list, and resource-read operations receive cache fields. Tool calls, prompt gets that return input_required, and any MRTR continuation never include ttlMs / cacheScope.

Inherited public predicates:

(none)

Public predicates

cache_policy/4

Returns the cache policy for a given operation and request. Operation is one of discover, tools_list, prompts_list, resources_list, resources_templates_list, or resources_read. Request is the request-specific identifier or arguments (e.g. a resource URI for resources_read, or a free term for list/discover). TTL is a non-negative integer (milliseconds). Scope is public or private. Failure means the server should use its configured defaults.

Compilation flags:

static

Template:

cache_policy(Operation,Request,TTL,Scope)

Mode and number of proofs:

cache_policy(+atom,+term,-integer,-atom) - zero_or_one

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Protected predicates

(none)

Private predicates

(none)

Operators

(none)