protocol

mcp_resource_protocol

Protocol for Logtalk objects that provide resources to be exposed via an MCP (Model Context Protocol) server. Implements the MCP 2025-06-18 specification. Implementing objects must define the set of resources available and handle resource read requests. Resources expose data and content from the application that MCP clients can access.

Availability:
logtalk_load(mcp_server(loader))
Author: Paulo Moura
Version: 0:2:0
Date: 2026-02-24
Compilation flags:
static
Dependencies:
(none)
Remarks:

  • Capabilities: Objects providing resources must declare resources in their capabilities/1 predicate (from the mcp_tool_protocol protocol). The server will then advertise the resources capability and handle resources/list and resources/read requests.

  • Resource descriptors: Each resource is described by a resource(URI, Name, Description, MimeType) or resource(URI, Name, Title, Description, MimeType) term where URI is the resource identifier (an atom), Name is a human-readable name (an atom), Title is an optional human-friendly display name (an atom), Description is a human-readable description (an atom), and MimeType is the MIME type of the resource content (an atom, e.g. 'text/plain').

  • Resource contents: The resource_read/3 predicate must return a result term. The result must be contents(ContentList) where each item is text_content(URI, MimeType, Text) for text resources or blob_content(URI, MimeType, Base64Data) for binary resources encoded as base64.

Inherited public predicates:
(none)

Public predicates

resources/1

Returns a list of resource descriptors available from this object. Each descriptor is a compound term resource(URI, Name, Description, MimeType) or resource(URI, Name, Title, Description, MimeType) where URI is the resource identifier (an atom, typically a URI like logtalk://my-app/data), Name is a human-readable name (an atom), Title is an optional human-friendly display name (an atom), Description is a human-readable description (an atom), and MimeType is the MIME type (an atom, e.g. 'text/plain', 'application/json').

Compilation flags:
static
Template:
resources(Resources)
Mode and number of proofs:
resources(-list(compound)) - one

resource_read/3

Handles a resource read request. URI is the resource identifier (as declared in resources/1), Arguments is a list of ArgumentName-Value pairs (currently unused but reserved for future use), and Result is unified with the resource result. The result must be contents(ContentList) where each content item is either text_content(URI, MimeType, Text) for text resources or blob_content(URI, MimeType, Base64Data) for binary resources encoded as base64. Text and Base64Data must be atoms.

Compilation flags:
static
Template:
resource_read(URI,Arguments,Result)
Mode and number of proofs:
resource_read(+atom,+list(pair),--compound) - one

Protected predicates

(none)

Private predicates

(none)

Operators

(none)