Mcp C 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.
Create/Dispose
HCkMcp instance = CkMcp_Create();
// ...
CkMcp_Dispose(instance);Creates an instance of the HCkMcp object and returns a handle ("void *" pointer). The handle is passed in the 1st argument for the functions listed on this page.
Objects created by calling CkMcp_Create must be freed by calling this method. A memory leak occurs if a handle is not disposed by calling this function. Also, any handle returned by a Chilkat "C" function must also be freed by the application by calling the appropriate Dispose method, such as CkMcp_Dispose.
Callback Functions
void CkMcp_setAbortCheck(HCkHttp cHandle, BOOL (*fnAbortCheck)(void));
Gives your application a chance to cancel a method call while it is running. Return TRUEFALSE
This callback fires periodically, at the interval set by the HeartbeatMs property. For example, set HeartbeatMs to 200 to receive five AbortCheck callbacks per second. If HeartbeatMs is 0, no callbacks are made and the operation cannot be aborted.
void CkMcp_setPercentDone(HCkHttp cHandle, BOOL (*fnPercentDone)(int pctDone));
Reports how far along a method call is, as a percentage. It applies to methods that involve network communication or time-consuming processing, and fires only when a percentage completed can actually be measured and it makes sense to express progress that way.
The pctDone argument is a value from 1 to 100. Methods that finish very quickly may produce only a few callbacks, but the final callback always reports 100. Long-running operations produce at most one callback per percentage point (for example: 1, 2, 3, … 98, 99, 100).
This callback also counts as an AbortCheck callback. When PercentDone fires, it replaces the AbortCheck callback that would otherwise have occurred at that moment.
The return value controls whether the method call continues. Return TRUEFALSE
void CkMcp_setProgressInfo(HCkHttp cHandle, void (*fnProgressInfo)(const char *name, const char *value));
A general-purpose callback that reports name/value pairs describing what is happening at various points during a method call. The information provided varies by method, and some methods provide none at all. To see what a particular method reports, write a handler that logs each name/value pair. Most are self-explanatory.
void CkMcp_setTaskCompleted(HCkHttp cHandle, void (*fnTaskCompleted)(HCkTask hTask));
Called when an asynchronous task finishes. This callback runs in the background thread rather than the thread that started the task. (While an async method is running, all callbacks occur in the background thread.)
Properties
AuthToken
void CkMcp_putAuthToken(HCkMcp cHandle, const char *newVal);
const char *CkMcp_authToken(HCkMcp cHandle);
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
void CkMcp_putConnectTimeoutMs(HCkMcp cHandle, int newVal);
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
void CkMcp_putDebugLogFilePath(HCkMcp cHandle, const char *newVal);
const char *CkMcp_debugLogFilePath(HCkMcp cHandle);
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.
HeartbeatMs
void CkMcp_putHeartbeatMs(HCkMcp cHandle, int newVal);
The interval in milliseconds between each AbortCheck event callback, which enables an application to abort a method before it completes. By default, HeartbeatMs is 0, meaning no AbortCheck event callbacks fire.
IdleTimeoutMs
void CkMcp_putIdleTimeoutMs(HCkMcp cHandle, int newVal);
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).
LastErrorHtml
const char *CkMcp_lastErrorHtml(HCkMcp cHandle);
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
const char *CkMcp_lastErrorText(HCkMcp cHandle);
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
const char *CkMcp_lastErrorXml(HCkMcp cHandle);
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
void CkMcp_putLastMethodSuccess(HCkMcp cHandle, BOOL newVal);
Indicates the success or failure of the most recent method call: TRUE means success, FALSE 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.
ProtocolVersion
void CkMcp_putProtocolVersion(HCkMcp cHandle, const char *newVal);
const char *CkMcp_protocolVersion(HCkMcp cHandle);
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
const char *CkMcp_serverInstructions(HCkMcp cHandle);
Read-only. Optional usage instructions provided by the server in the initialize result (may be the empty string), available after Connect.
ServerName
const char *CkMcp_serverName(HCkMcp cHandle);
ServerVersion
const char *CkMcp_serverVersion(HCkMcp cHandle);
SessionId
const char *CkMcp_sessionId(HCkMcp cHandle);
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.
Utf8
void CkMcp_putUtf8(HCkMcp cHandle, BOOL newVal);
When set to TRUE, all const char * arguments and return values are interpreted as UTF-8 strings. When set to FALSE, they are interpreted as ANSI strings.
In Chilkat v11.0.0 and later, the default value is TRUE. Before v11.0.0, it was FALSE.
VerboseLogging
void CkMcp_putVerboseLogging(HCkMcp cHandle, BOOL newVal);
If set to TRUE, then the contents of LastErrorText (or LastErrorXml, or LastErrorHtml) may contain more verbose information. The default value is FALSE. 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 TRUE here with isError set to TRUE in result (the failure message is typically carried in the content array). The return value is FALSE only for transport- or protocol-level failures.
Connect must be called first.
Returns TRUE for success, FALSE 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 TRUE for success, FALSE 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 TRUE.
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 TRUE for success, FALSE 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 TRUE for success, FALSE 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 TRUE for success, FALSE 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 TRUE for success, FALSE 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 TRUE for success, FALSE 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 TRUE for success, FALSE for failure.
ReadResourceAsync (1)
Creates an asynchronous task to call the ReadResource method with the arguments provided.
Returns NULL on failure