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Mycelium0.2.3
API reference

mcp

Import

Section titled “Import”
Import
import * as api from "@fungi.computer/mycelium/mcp";

Exports

Section titled “Exports”
Kind Export Description
type alias McpPrincipal Authenticated credential identity, scoped by its host. Never a bearer token.
type alias McpCatalogSnapshot Current installed capabilities and explicit grants for one admitted principal.
type alias McpAuthentication Admission is required on every HTTP request, including notifications.
type alias McpToolCall A JSON tool call submitted to the host’s execution owner.
type alias McpExecutionContext Request-scoped hooks carried into the same Mycelium runtime as hosted tools.
type alias McpCatalogSession A principal-bound catalog and its existing execution owner.
type alias McpCatalogProvider Host catalog adapter. All lookups and acquisitions are principal-bound.
type alias Mcp HTTP MCP lifecycle. Closing transport streams preserves host-owned Sessions.
type alias McpSessionMetadata Durable connection identity, without credentials or live execution callbacks.
type alias McpPersistence SDK-supported persistence; live protocol callbacks are never reconstructed.
function sameMcpPrincipal() Compare complete admitted identities, including a canonical member’s role.
function createMcpCatalog() Adapt principal-scoped capability sources and a sandbox to the shared MCP server. Connections are process-local. Durable hosts supply their own catalog provider.
function createMcp() Serve the host’s principal-bound Mycelium catalog through one MCP implementation.

McpPrincipaltype alias

Section titled “McpPrincipal”
Signature
type McpPrincipal =
  | Readonly<{
      actor: Extract<
        HostActor,
        {
          kind: "member";
        }
      >;
      role: "owner" | "member";
    }>
  | Readonly<{
      actor: Exclude<
        HostActor,
        {
          kind: "member";
        }
      >;
    }>;

Authenticated credential identity, scoped by its host. Never a bearer token.

McpCatalogSnapshottype alias

Section titled “McpCatalogSnapshot”
Signature
type McpCatalogSnapshot = Readonly<{
  instructions: string;
  sources: readonly CapabilitySource[];
  grants: Grants;
}>;

Current installed capabilities and explicit grants for one admitted principal.

McpAuthenticationtype alias

Section titled “McpAuthentication”
Signature
type McpAuthentication =
  | Readonly<{
      kind: "admitted";
      principal: McpPrincipal;
    }>
  | Readonly<{
      kind: "refused";
      status: 401 | 403 | 404 | 429;
      retryAfter?: number;
    }>;

Admission is required on every HTTP request, including notifications.

McpToolCalltype alias

Section titled “McpToolCall”
Signature
type McpToolCall = Readonly<{
  id: string;
  name: string;
  arguments: ToolCall["arguments"];
}>;

A JSON tool call submitted to the host’s execution owner.

McpExecutionContexttype alias

Section titled “McpExecutionContext”
Signature
type McpExecutionContext = Readonly<{
  signal: AbortSignal;
  onPart?: (part) => Promise<void>;
  access: Pick<AccessOptions, "confirm"> &
    Readonly<{
      beforeCall: (signal) => Promise<void>;
    }>;
}>;

Request-scoped hooks carried into the same Mycelium runtime as hosted tools.

McpCatalogSessiontype alias

Section titled “McpCatalogSession”
Signature
type McpCatalogSession = Readonly<{
  id: string;
  principal: McpPrincipal;
  refresh: () => Promise<void>;
  describe: () => Promise<{
    instructions: string;
    tools: readonly MuleTool["descriptor"][];
  }>;
  call: (call, context) => Promise<MuleToolResult>;
  disconnect: () => Promise<void>;
}>;

A principal-bound catalog and its existing execution owner.

McpCatalogProvidertype alias

Section titled “McpCatalogProvider”
Signature
type McpCatalogProvider = Readonly<{
  open: (principal, input) => Promise<McpCatalogSession | null>;
  resume: (principal, id) => Promise<McpCatalogSession | null>;
}>;

Host catalog adapter. All lookups and acquisitions are principal-bound.

Mcptype alias

Section titled “Mcp”
Signature
type Mcp = Readonly<{
  handleRequest: (request) => Promise<Response>;
  close: () => Promise<void>;
}>;

HTTP MCP lifecycle. Closing transport streams preserves host-owned Sessions.

McpSessionMetadatatype alias

Section titled “McpSessionMetadata”
Signature
type McpSessionMetadata = Readonly<{
  id: string;
  principal: McpPrincipal;
}>;

Durable connection identity, without credentials or live execution callbacks.

McpPersistencetype alias

Section titled “McpPersistence”
Signature
type McpPersistence = Readonly<{
  eventStore: (sessionId) => EventStore;
  initialized: (id, session) => Promise<void>;
  closed: (id, session) => Promise<void>;
}>;

SDK-supported persistence; live protocol callbacks are never reconstructed.

sameMcpPrincipal()function

Section titled “sameMcpPrincipal()”
Signature
function sameMcpPrincipal(left, right): boolean;

Compare complete admitted identities, including a canonical member’s role.

Parameters

Section titled “Parameters”
Parameter Type
left McpPrincipal
right McpPrincipal

Returns

Section titled “Returns”

boolean

createMcpCatalog()function

Section titled “createMcpCatalog()”
Signature
function createMcpCatalog(options): McpCatalogProvider;

Adapt principal-scoped capability sources and a sandbox to the shared MCP server. Connections are process-local. Durable hosts supply their own catalog provider.

Parameters

Section titled “Parameters”
Parameter Type
options Readonly<{ load: (principal) => Promise<McpCatalogSnapshot>; sandbox: Sandbox; }>

Returns

Section titled “Returns”

McpCatalogProvider

createMcp()function

Section titled “createMcp()”
Signature
function createMcp(options): Mcp;

Serve the host’s principal-bound Mycelium catalog through one MCP implementation.

Parameters

Section titled “Parameters”
Parameter Type
options Readonly<{ catalog: McpCatalogProvider; authenticate: (request) => Promise<McpAuthentication>; persistence?: McpPersistence; }>

Returns

Section titled “Returns”

Mcp