Mcp PowerBuilder Reference Documentation
Mcp
Current Version: 11.6.0
Chilkat.Mcp
Read resources with
Pass a connected A client for the Model Context Protocol (MCP).
Chilkat.Mcp connects to an MCP server and gives an application access to the
server's tools, resources, and prompts
over a single, unified API. MCP is an open protocol that standardizes how applications
supply context and callable tools to AI models.
Connect & handshake
Connect opens a Streamable HTTP session and performs
the MCP initialize handshake, negotiating the protocol version and
establishing a session id.
Resources & prompts
ListResources and
ReadResource, and fetch prompts with
ListPrompts and
GetPrompt.
Use with Chilkat.Ai
Chilkat.Mcp to Chilkat.Ai.UseMcp to register the
server's tools with an AI model. During a conversation the model's tool calls are
routed to the MCP server automatically.
Streamable HTTP transport
(protocol version 2025-06-18). A server response may arrive as a single JSON
object or as a Server-Sent-Events stream; both are handled transparently. The stdio
transport is not supported.
AuthToken property before calling
Connect. Chilkat then sends it as an
Authorization: Bearer <token> header on every request. Leave it
unset for servers that do not require authentication.
tools/list, resources/list, and prompts/list
results include a nextCursor string. In this release the list methods
return the first page only and do not accept a cursor argument, so nextCursor
is informational.
Object Creation
oleobject loo_Mcp
integer li_rc
loo_Mcp = create oleobject
li_rc = loo_Mcp.ConnectToNewObject("Chilkat.Mcp")
if li_rc < 0 then
destroy loo_Mcp
MessageBox("Error","Connecting to COM object failed")
return
end if
// ... use loo_Mcp ...
destroy loo_McpPowerBuilder uses the Chilkat ActiveX through an oleobject: declare the variable, create it, connect it to the Chilkat class with ConnectToNewObject, and destroy it when finished. A negative return code from ConnectToNewObject means the ActiveX is not registered, or the registered ActiveX does not match the bitness (32-bit or 64-bit) of the PowerBuilder target.
Objects returned by methods (such as an HttpResponse or JsonObject) are also oleobject variables and must likewise be destroyed. A method that fails to return an object returns null; test with IsNull(). In the signatures on this page, the Chilkat class name identifies which object is expected or returned; the PowerBuilder variable type is always oleobject.
To bind to a specific major version of Chilkat, append the major version number to the ProgID, such as ConnectToNewObject("Chilkat.Mcp.11") for Chilkat v11.*.*.
Members typed blob exchange binary data as a Variant byte array. The PowerBuilder examples instead use the BinData-based alternatives (methods ending in Bd), which keep binary data inside Chilkat objects.
Properties
AuthToken
An optional bearer token for authenticating to the MCP server. When set, it is sent as an Authorization: Bearer <token> header on every request. The default is the empty string.
Connected
ConnectTimeoutMs
The maximum amount of time, in milliseconds, to wait to establish the TCP/TLS connection to the MCP server. The default value is 30000 (30 seconds).
DebugLogFilePath
If set to a file path, this property logs the LastErrorText of each Chilkat method or property call to the specified file. This logging helps identify the context and history of Chilkat calls leading up to any crash or hang, aiding in debugging.
Enabling the VerboseLogging property provides more detailed information. This property is mainly used for debugging rare instances where a Chilkat method call causes a hang or crash, which should generally not happen.
Possible causes of hangs include:
- A timeout property set to 0, indicating an infinite timeout.
- A hang occurring within an event callback in the application code.
- An internal bug in the Chilkat code causing the hang.
IdleTimeoutMs
The maximum amount of time, in milliseconds, to wait for additional incoming data when receiving a response has paused. This is not a total timeout. The default value is 180000 (180 seconds).
LastBinaryResult
This property is mainly used in SQL Server stored procedures to retrieve binary data from the last method call that returned binary data. It is only accessible if Chilkat.Global.KeepBinaryResult is set to 1. This feature allows for the retrieval of large varbinary results in an SQL Server environment, which has restrictions on returning large data via method calls, though temp tables can handle binary properties.
LastErrorHtml
Provides HTML-formatted information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.
topLastErrorText
Provides plain text information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.
LastErrorXml
Provides XML-formatted information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.
topLastMethodSuccess
Indicates the success or failure of the most recent method call: 1 means success, 0 means failure. This property remains unchanged by property setters or getters. This method is present to address challenges in checking for null or Nothing returns in certain programming languages. Note: This property does not apply to methods that return integer values or to boolean-returning methods where the boolean does not indicate success or failure.
LastStringResult
In SQL Server stored procedures, this property holds the string return value of the most recent method call that returns a string. It is accessible only when Chilkat.Global.KeepStringResult is set to TRUE. SQL Server has limitations on string lengths returned from methods and properties, but temp tables can be used to access large strings.
LastStringResultLen
The length, in characters, of the string contained in the LastStringResult property.
topProtocolVersion
The MCP protocol version. May be set before Connect to request a specific version; after Connect it reflects the version negotiated with the server and is sent in the MCP-Protocol-Version header of each request. The default is 2025-06-18.
ServerInstructions
Read-only. Optional usage instructions provided by the server in the initialize result (may be the empty string), available after Connect.
ServerName
ServerVersion
SessionId
Read-only. The Mcp-Session-Id assigned by the server during the Connect handshake, or the empty string if the server is stateless. Chilkat automatically includes this session id on all subsequent requests.
VerboseLogging
If set to 1, then the contents of LastErrorText (or LastErrorXml, or LastErrorHtml) may contain more verbose information. The default value is 0. Verbose logging should only be used for debugging. The potentially large quantity of logged information may adversely affect peformance.
Version
Methods
CallTool
Calls the MCP tools/call method for the tool named name, passing the JSON arguments object in arguments. The members of arguments are the tool's input arguments and should match the tool's inputSchema as returned by ListTools. For example, a weather tool might be called with the arguments { "location": "Boston, MA", "units": "fahrenheit" }. Pass an empty JSON object (not a null) for a tool that takes no arguments.
On success, the tool result is placed in result. It contains a content array, an isError boolean, and optionally a structuredContent object. Each element of the content array has a type ("text", "image", "audio", or "resource"); for a "text" element the value is in its text member. A typical result looks like:
{
"content": [ { "type": "text", "text": "The weather in Boston is 72F and sunny." } ],
"isError": false
}
Thus the text of the first content item is at JSON path content[0].text.
Note: A tool that executes but reports a failure returns 1 here with isError set to 1 in result (the failure message is typically carried in the content array). The return value is 0 only for transport- or protocol-level failures.
Connect must be called first.
Returns 1 for success, 0 for failure.
CallToolAsync (1)
Creates an asynchronous task to call the CallTool method with the arguments provided.
Returns null on failure
Close
Explicitly terminates the MCP session by sending an HTTP DELETE with the Mcp-Session-Id header, then releases the connection. It is safe to call this method when not connected (it simply releases any transport). A server that does not permit client-terminated sessions responds with HTTP 405, which is not treated as an error.
Returns 1 for success, 0 for failure.
CloseAsync (1)
Creates an asynchronous task to call the Close method with the arguments provided.
Returns null on failure
Connect
Connects to the MCP (Model Context Protocol) server at the Streamable HTTP endpoint URL in url (for example https://example.com/mcp) and performs the MCP initialize handshake.
On success, the SessionId, ProtocolVersion, ServerName, ServerVersion, and ServerInstructions properties are populated, and Connected becomes 1.
If an AuthToken is set, it is sent as a bearer token on the request. The URL must begin with http:// or https://; the host, port, and path are taken from it. Only the Streamable HTTP transport is supported; the stdio transport is not.
Returns 1 for success, 0 for failure.
ConnectAsync (1)
Creates an asynchronous task to call the Connect method with the arguments provided.
Returns null on failure
GetLastJsonData
Returns, in json, the complete JSON-RPC response envelope from the most recent request (the jsonrpc, id, and result or error members), for diagnostics and logging. Note that this is the full JSON-RPC envelope, whereas ListTools, CallTool, ReadResource, and GetPrompt each return only the inner result object.
GetPrompt
Calls the MCP prompts/get method for the prompt named name, passing the JSON arguments object in arguments (pass an empty object for a prompt that takes no arguments). On success, the result is placed in json, consisting of an optional description and a messages array in which each message has a role and content.
Connect must be called first.
Returns 1 for success, 0 for failure.
GetPromptAsync (1)
Creates an asynchronous task to call the GetPrompt method with the arguments provided.
Returns null on failure
ListPrompts
Calls the MCP prompts/list method. On success, the server's result object is placed in json, containing a prompts array in which each prompt has a name, optionally a description, and an arguments array, and possibly a nextCursor for pagination.
Connect must be called first.
Returns 1 for success, 0 for failure.
ListPromptsAsync (1)
Creates an asynchronous task to call the ListPrompts method with the arguments provided.
Returns null on failure
ListResources
Calls the MCP resources/list method. On success, the server's result object is placed in json, containing a resources array in which each resource has a uri, a name, and optionally a description and mimeType, and possibly a nextCursor for pagination.
Connect must be called first.
Returns 1 for success, 0 for failure.
ListResourcesAsync (1)
Creates an asynchronous task to call the ListResources method with the arguments provided.
Returns null on failure
ListTools
Calls the MCP tools/list method. On success, the server's result object is placed in json, containing a tools array in which each tool has a name, a description, and an inputSchema (a JSON Schema describing the tool's arguments), and possibly a nextCursor for pagination.
Connect must be called first.
Returns 1 for success, 0 for failure.
ListToolsAsync (1)
Creates an asynchronous task to call the ListTools method with the arguments provided.
Returns null on failure
ReadResource
Calls the MCP resources/read method for the resource identified by the URI in uri. On success, the result is placed in json, containing a contents array whose entries carry a uri, a mimeType, and either text (for text resources) or blob (base64 for binary resources).
Connect must be called first.
Returns 1 for success, 0 for failure.
ReadResourceAsync (1)
Creates an asynchronous task to call the ReadResource method with the arguments provided.
Returns null on failure