+ Bases: BaseSession[ClientRequest, ClientNotification, ClientResult, ServerRequest, ServerNotification]
src/mcp/client/session.py103 +104 +105 +106 +107 +108 +109 +110 +111 +112 +113 +114 +115 +116 +117 +118 +119 +120 +121 +122 +123 +124 +125 +126 +127 +128 +129 +130 +131 +132 +133 +134 +135 +136 +137 +138 +139 +140 +141 +142 +143 +144 +145 +146 +147 +148 +149 +150 +151 +152 +153 +154 +155 +156 +157 +158 +159 +160 +161 +162 +163 +164 +165 +166 +167 +168 +169 +170 +171 +172 +173 +174 +175 +176 +177 +178 +179 +180 +181 +182 +183 +184 +185 +186 +187 +188 +189 +190 +191 +192 +193 +194 +195 +196 +197 +198 +199 +200 +201 +202 +203 +204 +205 +206 +207 +208 +209 +210 +211 +212 +213 +214 +215 +216 +217 +218 +219 +220 +221 +222 +223 +224 +225 +226 +227 +228 +229 +230 +231 +232 +233 +234 +235 +236 +237 +238 +239 +240 +241 +242 +243 +244 +245 +246 +247 +248 +249 +250 +251 +252 +253 +254 +255 +256 +257 +258 +259 +260 +261 +262 +263 +264 +265 +266 +267 +268 +269 +270 +271 +272 +273 +274 +275 +276 +277 +278 +279 +280 +281 +282 +283 +284 +285 +286 +287 +288 +289 +290 +291 +292 +293 +294 +295 +296 +297 +298 +299 +300 +301 +302 +303 +304 +305 +306 +307 +308 +309 +310 +311 +312 +313 +314 +315 +316 +317 +318 +319 +320 +321 +322 +323 +324 +325 +326 +327 +328 +329 +330 +331 +332 +333 +334 +335 +336 +337 +338 +339 +340 +341 +342 +343 +344 +345 +346 +347 +348 +349 +350 +351 +352 +353 +354 +355 +356 +357 +358 +359 +360 +361 +362 +363 +364 +365 +366 +367 +368 +369 +370 +371 +372 +373 +374 +375 +376 +377 +378 +379 +380 +381 +382 +383 +384 +385 +386 +387 +388 +389 +390 +391 +392 +393 +394 +395 +396 +397 +398 +399 +400 +401 +402 +403 +404 +405 +406 +407 +408 +409 +410 +411 +412 +413 +414 +415 +416 +417 +418 +419 +420 +421 +422 +423 +424 +425 +426 +427 +428 +429 +430 +431 +432 +433 +434 +435 +436 +437 +438 +439 +440 +441 +442 +443 +444 +445 +446 +447 +448 +449 +450 +451 +452 +453 +454 +455 +456 +457 +458 +459 +460 +461 +462 +463 +464 +465 +466 +467 +468 +469 +470 +471 +472 +473 +474 +475 +476 +477 +478 +479 +480 +481 +482 +483 +484 +485 +486 +487 +488 +489 +490 +491 +492 +493 +494 +495 +496 +497 +498 +499 +500 +501 +502 +503 +504 +505 +506 +507 +508 +509 +510 +511 +512 +513 +514 +515 +516 +517 +518 +519 +520 +521 +522 +523 +524 +525 +526 +527 +528 +529 +530 +531 +532 +533 +534 +535 +536 +537 +538 +539 +540 +541 +542 +543 +544 +545 +546 +547 +548 +549 +550 +551 +552 +553 +554 +555 +556 +557 +558 +559 +560 +561 +562 +563 +564 +565 +566 +567 +568 +569 +570 +571 +572 +573 +574 +575 +576 +577 +578 +579 +580 +581 +582 +583 +584 +585 +586 +587 +588 +589 +590 +591 +592 +593 +594 +595 +596 +597 +598 +599 +600 +601 +602 +603 +604 +605 +606 +607 +608 +609 +610 +611 +612 +613 +614 +615 | |
get_server_capabilities() -> ServerCapabilities | None
+Return the server capabilities received during initialization.
+Returns None if the session has not been initialized yet.
+ + +src/mcp/client/session.py199 +200 +201 +202 +203 +204 | |
property
+
+
+experimental: ExperimentalClientFeatures
+Experimental APIs for tasks and other features.
+WARNING: These APIs are experimental and may change without notice.
+ + +status = await session.experimental.get_task(task_id) +result = await session.experimental.get_task_result(task_id, CallToolResult)
+async
+
+
+send_ping() -> EmptyResult
+Send a ping request.
+ + +src/mcp/client/session.py220 +221 +222 +223 +224 +225 | |
async
+
+
+send_progress_notification(
+ progress_token: str | int,
+ progress: float,
+ total: float | None = None,
+ message: str | None = None,
+) -> None
+Send a progress notification.
+ + +src/mcp/client/session.py227 +228 +229 +230 +231 +232 +233 +234 +235 +236 +237 +238 +239 +240 +241 +242 +243 +244 +245 +246 | |
async
+
+
+set_logging_level(level: LoggingLevel) -> EmptyResult
+Send a logging/setLevel request.
+ + +src/mcp/client/session.py248 +249 +250 +251 +252 +253 +254 +255 +256 +257 | |
async
+
+
+list_resources(cursor: str | None) -> ListResourcesResult
+list_resources(
+ *, params: PaginatedRequestParams | None
+) -> ListResourcesResult
+list_resources() -> ListResourcesResult
+list_resources(
+ cursor: str | None = None,
+ *,
+ params: PaginatedRequestParams | None = None
+) -> ListResourcesResult
+Send a resources/list request.
+ + +Parameters:
+| Name | +Type | +Description | +Default | +
|---|---|---|---|
+ cursor
+ |
+
+ str | None
+ |
+
+
+
+ Simple cursor string for pagination (deprecated, use params instead) + |
+
+ None
+ |
+
+ params
+ |
+
+ PaginatedRequestParams | None
+ |
+
+
+
+ Full pagination parameters including cursor and any future fields + |
+
+ None
+ |
+
src/mcp/client/session.py269 +270 +271 +272 +273 +274 +275 +276 +277 +278 +279 +280 +281 +282 +283 +284 +285 +286 +287 +288 +289 +290 +291 +292 +293 +294 | |
async
+
+
+list_resource_templates(
+ cursor: str | None,
+) -> ListResourceTemplatesResult
+list_resource_templates(
+ *, params: PaginatedRequestParams | None
+) -> ListResourceTemplatesResult
+list_resource_templates() -> ListResourceTemplatesResult
+list_resource_templates(
+ cursor: str | None = None,
+ *,
+ params: PaginatedRequestParams | None = None
+) -> ListResourceTemplatesResult
+Send a resources/templates/list request.
+ + +Parameters:
+| Name | +Type | +Description | +Default | +
|---|---|---|---|
+ cursor
+ |
+
+ str | None
+ |
+
+
+
+ Simple cursor string for pagination (deprecated, use params instead) + |
+
+ None
+ |
+
+ params
+ |
+
+ PaginatedRequestParams | None
+ |
+
+
+
+ Full pagination parameters including cursor and any future fields + |
+
+ None
+ |
+
src/mcp/client/session.py308 +309 +310 +311 +312 +313 +314 +315 +316 +317 +318 +319 +320 +321 +322 +323 +324 +325 +326 +327 +328 +329 +330 +331 +332 +333 | |
async
+
+
+read_resource(uri: AnyUrl) -> ReadResourceResult
+Send a resources/read request.
+ + +src/mcp/client/session.py335 +336 +337 +338 +339 +340 +341 +342 +343 +344 | |
async
+
+
+subscribe_resource(uri: AnyUrl) -> EmptyResult
+Send a resources/subscribe request.
+ + +src/mcp/client/session.py346 +347 +348 +349 +350 +351 +352 +353 +354 +355 | |
async
+
+
+unsubscribe_resource(uri: AnyUrl) -> EmptyResult
+Send a resources/unsubscribe request.
+ + +src/mcp/client/session.py357 +358 +359 +360 +361 +362 +363 +364 +365 +366 | |
async
+
+
+call_tool(
+ name: str,
+ arguments: dict[str, Any] | None = None,
+ read_timeout_seconds: timedelta | None = None,
+ progress_callback: ProgressFnT | None = None,
+ *,
+ meta: dict[str, Any] | None = None
+) -> CallToolResult
+Send a tools/call request with optional progress callback support.
+ + +src/mcp/client/session.py368 +369 +370 +371 +372 +373 +374 +375 +376 +377 +378 +379 +380 +381 +382 +383 +384 +385 +386 +387 +388 +389 +390 +391 +392 +393 +394 +395 +396 +397 | |
async
+
+
+list_prompts(cursor: str | None) -> ListPromptsResult
+list_prompts(
+ *, params: PaginatedRequestParams | None
+) -> ListPromptsResult
+list_prompts() -> ListPromptsResult
+list_prompts(
+ cursor: str | None = None,
+ *,
+ params: PaginatedRequestParams | None = None
+) -> ListPromptsResult
+Send a prompts/list request.
+ + +Parameters:
+| Name | +Type | +Description | +Default | +
|---|---|---|---|
+ cursor
+ |
+
+ str | None
+ |
+
+
+
+ Simple cursor string for pagination (deprecated, use params instead) + |
+
+ None
+ |
+
+ params
+ |
+
+ PaginatedRequestParams | None
+ |
+
+
+
+ Full pagination parameters including cursor and any future fields + |
+
+ None
+ |
+
src/mcp/client/session.py435 +436 +437 +438 +439 +440 +441 +442 +443 +444 +445 +446 +447 +448 +449 +450 +451 +452 +453 +454 +455 +456 +457 +458 +459 +460 | |
async
+
+
+get_prompt(
+ name: str, arguments: dict[str, str] | None = None
+) -> GetPromptResult
+Send a prompts/get request.
+ + +src/mcp/client/session.py462 +463 +464 +465 +466 +467 +468 +469 +470 +471 | |
async
+
+
+complete(
+ ref: ResourceTemplateReference | PromptReference,
+ argument: dict[str, str],
+ context_arguments: dict[str, str] | None = None,
+) -> CompleteResult
+Send a completion/complete request.
+ + +src/mcp/client/session.py473 +474 +475 +476 +477 +478 +479 +480 +481 +482 +483 +484 +485 +486 +487 +488 +489 +490 +491 +492 +493 +494 +495 | |
async
+
+
+list_tools(cursor: str | None) -> ListToolsResult
+list_tools(
+ *, params: PaginatedRequestParams | None
+) -> ListToolsResult
+list_tools() -> ListToolsResult
+list_tools(
+ cursor: str | None = None,
+ *,
+ params: PaginatedRequestParams | None = None
+) -> ListToolsResult
+Send a tools/list request.
+ + +Parameters:
+| Name | +Type | +Description | +Default | +
|---|---|---|---|
+ cursor
+ |
+
+ str | None
+ |
+
+
+
+ Simple cursor string for pagination (deprecated, use params instead) + |
+
+ None
+ |
+
+ params
+ |
+
+ PaginatedRequestParams | None
+ |
+
+
+
+ Full pagination parameters including cursor and any future fields + |
+
+ None
+ |
+
src/mcp/client/session.py507 +508 +509 +510 +511 +512 +513 +514 +515 +516 +517 +518 +519 +520 +521 +522 +523 +524 +525 +526 +527 +528 +529 +530 +531 +532 +533 +534 +535 +536 +537 +538 +539 | |
async
+
+
+send_roots_list_changed() -> None
+Send a roots/list_changed notification.
+ + +src/mcp/client/session.py541 +542 +543 | |
Client for managing connections to multiple MCP servers.
+This class is responsible for encapsulating management of server connections. +It aggregates tools, resources, and prompts from all connected servers.
+For auxiliary handlers, such as resource subscription, this is delegated to +the client and can be accessed via the session.
+ + +name_fn = lambda name, server_info: f"{(server_info.name)}_{name}" +async with ClientSessionGroup(component_name_hook=name_fn) as group: + for server_param in server_params: + await group.connect_to_server(server_param) + ...
+src/mcp/client/session_group.py88 + 89 + 90 + 91 + 92 + 93 + 94 + 95 + 96 + 97 + 98 + 99 +100 +101 +102 +103 +104 +105 +106 +107 +108 +109 +110 +111 +112 +113 +114 +115 +116 +117 +118 +119 +120 +121 +122 +123 +124 +125 +126 +127 +128 +129 +130 +131 +132 +133 +134 +135 +136 +137 +138 +139 +140 +141 +142 +143 +144 +145 +146 +147 +148 +149 +150 +151 +152 +153 +154 +155 +156 +157 +158 +159 +160 +161 +162 +163 +164 +165 +166 +167 +168 +169 +170 +171 +172 +173 +174 +175 +176 +177 +178 +179 +180 +181 +182 +183 +184 +185 +186 +187 +188 +189 +190 +191 +192 +193 +194 +195 +196 +197 +198 +199 +200 +201 +202 +203 +204 +205 +206 +207 +208 +209 +210 +211 +212 +213 +214 +215 +216 +217 +218 +219 +220 +221 +222 +223 +224 +225 +226 +227 +228 +229 +230 +231 +232 +233 +234 +235 +236 +237 +238 +239 +240 +241 +242 +243 +244 +245 +246 +247 +248 +249 +250 +251 +252 +253 +254 +255 +256 +257 +258 +259 +260 +261 +262 +263 +264 +265 +266 +267 +268 +269 +270 +271 +272 +273 +274 +275 +276 +277 +278 +279 +280 +281 +282 +283 +284 +285 +286 +287 +288 +289 +290 +291 +292 +293 +294 +295 +296 +297 +298 +299 +300 +301 +302 +303 +304 +305 +306 +307 +308 +309 +310 +311 +312 +313 +314 +315 +316 +317 +318 +319 +320 +321 +322 +323 +324 +325 +326 +327 +328 +329 +330 +331 +332 +333 +334 +335 +336 +337 +338 +339 +340 +341 +342 +343 +344 +345 +346 +347 +348 +349 +350 +351 +352 +353 +354 +355 +356 +357 +358 +359 +360 +361 +362 +363 +364 +365 +366 +367 +368 +369 +370 +371 +372 +373 +374 +375 +376 +377 +378 +379 +380 +381 +382 +383 +384 +385 +386 +387 +388 +389 +390 +391 +392 +393 +394 +395 +396 +397 +398 +399 +400 +401 +402 +403 +404 +405 +406 +407 +408 +409 +410 +411 +412 +413 +414 +415 +416 +417 +418 +419 +420 +421 +422 +423 +424 +425 +426 +427 +428 +429 +430 +431 +432 +433 +434 +435 +436 +437 +438 +439 +440 +441 +442 +443 +444 +445 +446 +447 | |
__init__(
+ exit_stack: AsyncExitStack | None = None,
+ component_name_hook: _ComponentNameHook | None = None,
+) -> None
+Initializes the MCP client.
+ + +src/mcp/client/session_group.py130 +131 +132 +133 +134 +135 +136 +137 +138 +139 +140 +141 +142 +143 +144 +145 +146 +147 +148 +149 +150 | |
async
+
+
+__aexit__(
+ _exc_type: type[BaseException] | None,
+ _exc_val: BaseException | None,
+ _exc_tb: TracebackType | None,
+) -> bool | None
+Closes session exit stacks and main exit stack upon completion.
+ + +src/mcp/client/session_group.py158 +159 +160 +161 +162 +163 +164 +165 +166 +167 +168 +169 +170 +171 +172 +173 | |
property
+
+
+sessions: list[ClientSession]
+Returns the list of sessions being managed.
+ +property
+
+
+Returns the prompts as a dictionary of names to prompts.
+ +property
+
+
+Returns the resources as a dictionary of names to resources.
+ +property
+
+
+Returns the tools as a dictionary of names to tools.
+ +async
+
+
+call_tool(
+ name: str,
+ arguments: dict[str, Any] | None = None,
+ read_timeout_seconds: timedelta | None = None,
+ progress_callback: ProgressFnT | None = None,
+ *,
+ meta: dict[str, Any] | None = None,
+ args: dict[str, Any] | None = None
+) -> CallToolResult
+Executes a tool given its name and arguments.
+ + +src/mcp/client/session_group.py218 +219 +220 +221 +222 +223 +224 +225 +226 +227 +228 +229 +230 +231 +232 +233 +234 +235 +236 +237 | |
async
+
+
+disconnect_from_server(session: ClientSession) -> None
+Disconnects from a single MCP server.
+ + +src/mcp/client/session_group.py239 +240 +241 +242 +243 +244 +245 +246 +247 +248 +249 +250 +251 +252 +253 +254 +255 +256 +257 +258 +259 +260 +261 +262 +263 +264 +265 +266 +267 +268 +269 +270 +271 +272 +273 +274 | |
async
+
+
+connect_with_session(
+ server_info: Implementation, session: ClientSession
+) -> ClientSession
+Connects to a single MCP server.
+ + +src/mcp/client/session_group.py276 +277 +278 +279 +280 +281 | |
async
+
+
+connect_to_server(
+ server_params: ServerParameters,
+ session_params: ClientSessionParameters | None = None,
+) -> ClientSession
+Connects to a single MCP server.
+ + +src/mcp/client/session_group.py283 +284 +285 +286 +287 +288 +289 +290 | |
+ Bases: BaseModel
src/mcp/client/stdio/__init__.py72 + 73 + 74 + 75 + 76 + 77 + 78 + 79 + 80 + 81 + 82 + 83 + 84 + 85 + 86 + 87 + 88 + 89 + 90 + 91 + 92 + 93 + 94 + 95 + 96 + 97 + 98 + 99 +100 +101 +102 | |
instance-attribute
+
+
+command: str
+The executable to run to start the server.
+ +class-attribute
+ instance-attribute
+
+
+Command line arguments to pass to the executable.
+ +class-attribute
+ instance-attribute
+
+
+The environment to use when spawning the process.
+If not specified, the result of get_default_environment() will be used.
+ +class-attribute
+ instance-attribute
+
+
+The working directory to use when spawning the process.
+ +class-attribute
+ instance-attribute
+
+
+encoding: str = 'utf-8'
+The text encoding used when sending/receiving messages to the server
+defaults to utf-8
+ +class-attribute
+ instance-attribute
+
+
+encoding_error_handler: Literal[
+ "strict", "ignore", "replace"
+] = "strict"
+The text encoding error handler.
+See https://docs.python.org/3/library/codecs.html#codec-base-classes for +explanations of possible values
+ +async
+
+
+stdio_client(
+ server: StdioServerParameters, errlog: TextIO = stderr
+)
+Client transport for stdio: this will connect to a server by spawning a +process and communicating with it over stdin/stdout.
+ + +src/mcp/client/stdio/__init__.py105 +106 +107 +108 +109 +110 +111 +112 +113 +114 +115 +116 +117 +118 +119 +120 +121 +122 +123 +124 +125 +126 +127 +128 +129 +130 +131 +132 +133 +134 +135 +136 +137 +138 +139 +140 +141 +142 +143 +144 +145 +146 +147 +148 +149 +150 +151 +152 +153 +154 +155 +156 +157 +158 +159 +160 +161 +162 +163 +164 +165 +166 +167 +168 +169 +170 +171 +172 +173 +174 +175 +176 +177 +178 +179 +180 +181 +182 +183 +184 +185 +186 +187 +188 +189 +190 +191 +192 +193 +194 +195 +196 +197 +198 +199 +200 +201 +202 +203 +204 +205 +206 +207 +208 +209 +210 +211 +212 +213 +214 +215 +216 | |
+ Bases: BaseSession[ServerRequest, ServerNotification, ServerResult, ClientRequest, ClientNotification]
src/mcp/server/session.py75 + 76 + 77 + 78 + 79 + 80 + 81 + 82 + 83 + 84 + 85 + 86 + 87 + 88 + 89 + 90 + 91 + 92 + 93 + 94 + 95 + 96 + 97 + 98 + 99 +100 +101 +102 +103 +104 +105 +106 +107 +108 +109 +110 +111 +112 +113 +114 +115 +116 +117 +118 +119 +120 +121 +122 +123 +124 +125 +126 +127 +128 +129 +130 +131 +132 +133 +134 +135 +136 +137 +138 +139 +140 +141 +142 +143 +144 +145 +146 +147 +148 +149 +150 +151 +152 +153 +154 +155 +156 +157 +158 +159 +160 +161 +162 +163 +164 +165 +166 +167 +168 +169 +170 +171 +172 +173 +174 +175 +176 +177 +178 +179 +180 +181 +182 +183 +184 +185 +186 +187 +188 +189 +190 +191 +192 +193 +194 +195 +196 +197 +198 +199 +200 +201 +202 +203 +204 +205 +206 +207 +208 +209 +210 +211 +212 +213 +214 +215 +216 +217 +218 +219 +220 +221 +222 +223 +224 +225 +226 +227 +228 +229 +230 +231 +232 +233 +234 +235 +236 +237 +238 +239 +240 +241 +242 +243 +244 +245 +246 +247 +248 +249 +250 +251 +252 +253 +254 +255 +256 +257 +258 +259 +260 +261 +262 +263 +264 +265 +266 +267 +268 +269 +270 +271 +272 +273 +274 +275 +276 +277 +278 +279 +280 +281 +282 +283 +284 +285 +286 +287 +288 +289 +290 +291 +292 +293 +294 +295 +296 +297 +298 +299 +300 +301 +302 +303 +304 +305 +306 +307 +308 +309 +310 +311 +312 +313 +314 +315 +316 +317 +318 +319 +320 +321 +322 +323 +324 +325 +326 +327 +328 +329 +330 +331 +332 +333 +334 +335 +336 +337 +338 +339 +340 +341 +342 +343 +344 +345 +346 +347 +348 +349 +350 +351 +352 +353 +354 +355 +356 +357 +358 +359 +360 +361 +362 +363 +364 +365 +366 +367 +368 +369 +370 +371 +372 +373 +374 +375 +376 +377 +378 +379 +380 +381 +382 +383 +384 +385 +386 +387 +388 +389 +390 +391 +392 +393 +394 +395 +396 +397 +398 +399 +400 +401 +402 +403 +404 +405 +406 +407 +408 +409 +410 +411 +412 +413 +414 +415 +416 +417 +418 +419 +420 +421 +422 +423 +424 +425 +426 +427 +428 +429 +430 +431 +432 +433 +434 +435 +436 +437 +438 +439 +440 +441 +442 +443 +444 +445 +446 +447 +448 +449 +450 +451 +452 +453 +454 +455 +456 +457 +458 +459 +460 +461 +462 +463 +464 +465 +466 +467 +468 +469 +470 +471 +472 +473 +474 +475 +476 +477 +478 +479 +480 +481 +482 +483 +484 +485 +486 +487 +488 +489 +490 +491 +492 +493 +494 +495 +496 +497 +498 +499 +500 +501 +502 +503 +504 +505 +506 +507 +508 +509 +510 +511 +512 +513 +514 +515 +516 +517 +518 +519 +520 +521 +522 +523 +524 +525 +526 +527 +528 +529 +530 +531 +532 +533 +534 +535 +536 +537 +538 +539 +540 +541 +542 +543 +544 +545 +546 +547 +548 +549 +550 +551 +552 +553 +554 +555 +556 +557 +558 +559 +560 +561 +562 +563 +564 +565 +566 +567 +568 +569 +570 +571 +572 +573 +574 +575 +576 +577 +578 +579 +580 +581 +582 +583 +584 +585 +586 +587 +588 +589 +590 +591 +592 +593 +594 +595 +596 +597 +598 +599 +600 +601 +602 +603 +604 +605 +606 +607 +608 +609 +610 +611 +612 +613 +614 +615 +616 +617 +618 +619 +620 +621 +622 +623 +624 +625 +626 +627 +628 +629 +630 +631 +632 +633 +634 +635 +636 +637 +638 +639 +640 +641 +642 +643 +644 +645 +646 +647 +648 +649 +650 +651 +652 +653 +654 +655 +656 +657 +658 +659 +660 +661 +662 +663 +664 +665 +666 +667 +668 +669 +670 +671 +672 +673 +674 +675 +676 +677 +678 +679 +680 +681 +682 +683 +684 +685 +686 +687 +688 +689 +690 +691 | |
property
+
+
+experimental: ExperimentalServerSessionFeatures
+Experimental APIs for server→client task operations.
+WARNING: These APIs are experimental and may change without notice.
+ +check_client_capability(
+ capability: ClientCapabilities,
+) -> bool
+Check if the client supports a specific capability.
+ + +src/mcp/server/session.py120 +121 +122 +123 +124 +125 +126 +127 +128 +129 +130 +131 +132 +133 +134 +135 +136 +137 +138 +139 +140 +141 +142 +143 +144 +145 +146 +147 +148 +149 +150 +151 +152 +153 +154 +155 +156 +157 | |
async
+
+
+send_log_message(
+ level: LoggingLevel,
+ data: Any,
+ logger: str | None = None,
+ related_request_id: RequestId | None = None,
+) -> None
+Send a log message notification.
+ + +src/mcp/server/session.py205 +206 +207 +208 +209 +210 +211 +212 +213 +214 +215 +216 +217 +218 +219 +220 +221 +222 +223 +224 | |
async
+
+
+send_resource_updated(uri: AnyUrl) -> None
+Send a resource updated notification.
+ + +src/mcp/server/session.py226 +227 +228 +229 +230 +231 +232 +233 +234 | |
async
+
+
+create_message(
+ messages: list[SamplingMessage],
+ *,
+ max_tokens: int,
+ system_prompt: str | None = None,
+ include_context: IncludeContext | None = None,
+ temperature: float | None = None,
+ stop_sequences: list[str] | None = None,
+ metadata: dict[str, Any] | None = None,
+ model_preferences: ModelPreferences | None = None,
+ tools: None = None,
+ tool_choice: ToolChoice | None = None,
+ related_request_id: RequestId | None = None
+) -> CreateMessageResult
+create_message(
+ messages: list[SamplingMessage],
+ *,
+ max_tokens: int,
+ system_prompt: str | None = None,
+ include_context: IncludeContext | None = None,
+ temperature: float | None = None,
+ stop_sequences: list[str] | None = None,
+ metadata: dict[str, Any] | None = None,
+ model_preferences: ModelPreferences | None = None,
+ tools: list[Tool],
+ tool_choice: ToolChoice | None = None,
+ related_request_id: RequestId | None = None
+) -> CreateMessageResultWithTools
+create_message(
+ messages: list[SamplingMessage],
+ *,
+ max_tokens: int,
+ system_prompt: str | None = None,
+ include_context: IncludeContext | None = None,
+ temperature: float | None = None,
+ stop_sequences: list[str] | None = None,
+ metadata: dict[str, Any] | None = None,
+ model_preferences: ModelPreferences | None = None,
+ tools: list[Tool] | None = None,
+ tool_choice: ToolChoice | None = None,
+ related_request_id: RequestId | None = None
+) -> CreateMessageResult | CreateMessageResultWithTools
+Send a sampling/create_message request.
+ + +Parameters:
+| Name | +Type | +Description | +Default | +
|---|---|---|---|
+ messages
+ |
+
+ list[SamplingMessage]
+ |
+
+
+
+ The conversation messages to send. + |
+ + required + | +
+ max_tokens
+ |
+
+ int
+ |
+
+
+
+ Maximum number of tokens to generate. + |
+ + required + | +
+ system_prompt
+ |
+
+ str | None
+ |
+
+
+
+ Optional system prompt. + |
+
+ None
+ |
+
+ include_context
+ |
+
+ IncludeContext | None
+ |
+
+
+
+ Optional context inclusion setting. +Should only be set to "thisServer" or "allServers" +if the client has sampling.context capability. + |
+
+ None
+ |
+
+ temperature
+ |
+
+ float | None
+ |
+
+
+
+ Optional sampling temperature. + |
+
+ None
+ |
+
+ stop_sequences
+ |
+
+ list[str] | None
+ |
+
+
+
+ Optional stop sequences. + |
+
+ None
+ |
+
+ metadata
+ |
+
+ dict[str, Any] | None
+ |
+
+
+
+ Optional metadata to pass through to the LLM provider. + |
+
+ None
+ |
+
+ model_preferences
+ |
+
+ ModelPreferences | None
+ |
+
+
+
+ Optional model selection preferences. + |
+
+ None
+ |
+
+ tools
+ |
+
+ list[Tool] | None
+ |
+
+
+
+ Optional list of tools the LLM can use during sampling. +Requires client to have sampling.tools capability. + |
+
+ None
+ |
+
+ tool_choice
+ |
+
+ ToolChoice | None
+ |
+
+
+
+ Optional control over tool usage behavior. +Requires client to have sampling.tools capability. + |
+
+ None
+ |
+
+ related_request_id
+ |
+
+ RequestId | None
+ |
+
+
+
+ Optional ID of a related request. + |
+
+ None
+ |
+
Returns:
+| Type | +Description | +
|---|---|
+ CreateMessageResult | CreateMessageResultWithTools
+ |
+
+
+
+ The sampling result from the client. + |
+
Raises:
+| Type | +Description | +
|---|---|
+ McpError
+ |
+
+
+
+ If tools are provided but client doesn't support them. + |
+
+ ValueError
+ |
+
+
+
+ If tool_use or tool_result message structure is invalid. + |
+
src/mcp/server/session.py274 +275 +276 +277 +278 +279 +280 +281 +282 +283 +284 +285 +286 +287 +288 +289 +290 +291 +292 +293 +294 +295 +296 +297 +298 +299 +300 +301 +302 +303 +304 +305 +306 +307 +308 +309 +310 +311 +312 +313 +314 +315 +316 +317 +318 +319 +320 +321 +322 +323 +324 +325 +326 +327 +328 +329 +330 +331 +332 +333 +334 +335 +336 +337 +338 +339 +340 +341 +342 +343 +344 +345 +346 +347 +348 | |
async
+
+
+list_roots() -> ListRootsResult
+Send a roots/list request.
+ + +src/mcp/server/session.py350 +351 +352 +353 +354 +355 | |
async
+
+
+elicit(
+ message: str,
+ requestedSchema: ElicitRequestedSchema,
+ related_request_id: RequestId | None = None,
+) -> ElicitResult
+Send a form mode elicitation/create request.
+ + +Parameters:
+| Name | +Type | +Description | +Default | +
|---|---|---|---|
+ message
+ |
+
+ str
+ |
+
+
+
+ The message to present to the user + |
+ + required + | +
+ requestedSchema
+ |
+
+ ElicitRequestedSchema
+ |
+
+
+
+ Schema defining the expected response structure + |
+ + required + | +
+ related_request_id
+ |
+
+ RequestId | None
+ |
+
+
+
+ Optional ID of the request that triggered this elicitation + |
+
+ None
+ |
+
Returns:
+| Type | +Description | +
|---|---|
+ ElicitResult
+ |
+
+
+
+ The client's response + |
+
This method is deprecated in favor of elicit_form(). It remains for +backward compatibility but new code should use elicit_form().
+src/mcp/server/session.py357 +358 +359 +360 +361 +362 +363 +364 +365 +366 +367 +368 +369 +370 +371 +372 +373 +374 +375 +376 +377 | |
async
+
+
+elicit_form(
+ message: str,
+ requestedSchema: ElicitRequestedSchema,
+ related_request_id: RequestId | None = None,
+) -> ElicitResult
+Send a form mode elicitation/create request.
+ + +Parameters:
+| Name | +Type | +Description | +Default | +
|---|---|---|---|
+ message
+ |
+
+ str
+ |
+
+
+
+ The message to present to the user + |
+ + required + | +
+ requestedSchema
+ |
+
+ ElicitRequestedSchema
+ |
+
+
+
+ Schema defining the expected response structure + |
+ + required + | +
+ related_request_id
+ |
+
+ RequestId | None
+ |
+
+
+
+ Optional ID of the request that triggered this elicitation + |
+
+ None
+ |
+
Returns:
+| Type | +Description | +
|---|---|
+ ElicitResult
+ |
+
+
+
+ The client's response with form data + |
+
src/mcp/server/session.py379 +380 +381 +382 +383 +384 +385 +386 +387 +388 +389 +390 +391 +392 +393 +394 +395 +396 +397 +398 +399 +400 +401 +402 +403 +404 +405 +406 | |
async
+
+
+elicit_url(
+ message: str,
+ url: str,
+ elicitation_id: str,
+ related_request_id: RequestId | None = None,
+) -> ElicitResult
+Send a URL mode elicitation/create request.
+This directs the user to an external URL for out-of-band interactions +like OAuth flows, credential collection, or payment processing.
+ + +Parameters:
+| Name | +Type | +Description | +Default | +
|---|---|---|---|
+ message
+ |
+
+ str
+ |
+
+
+
+ Human-readable explanation of why the interaction is needed + |
+ + required + | +
+ url
+ |
+
+ str
+ |
+
+
+
+ The URL the user should navigate to + |
+ + required + | +
+ elicitation_id
+ |
+
+ str
+ |
+
+
+
+ Unique identifier for tracking this elicitation + |
+ + required + | +
+ related_request_id
+ |
+
+ RequestId | None
+ |
+
+
+
+ Optional ID of the request that triggered this elicitation + |
+
+ None
+ |
+
Returns:
+| Type | +Description | +
|---|---|
+ ElicitResult
+ |
+
+
+
+ The client's response indicating acceptance, decline, or cancellation + |
+
src/mcp/server/session.py408 +409 +410 +411 +412 +413 +414 +415 +416 +417 +418 +419 +420 +421 +422 +423 +424 +425 +426 +427 +428 +429 +430 +431 +432 +433 +434 +435 +436 +437 +438 +439 +440 +441 | |
async
+
+
+send_ping() -> EmptyResult
+Send a ping request.
+ + +src/mcp/server/session.py443 +444 +445 +446 +447 +448 | |
async
+
+
+send_progress_notification(
+ progress_token: str | int,
+ progress: float,
+ total: float | None = None,
+ message: str | None = None,
+ related_request_id: str | None = None,
+) -> None
+Send a progress notification.
+ + +src/mcp/server/session.py450 +451 +452 +453 +454 +455 +456 +457 +458 +459 +460 +461 +462 +463 +464 +465 +466 +467 +468 +469 +470 +471 | |
async
+
+
+send_resource_list_changed() -> None
+Send a resource list changed notification.
+ + +src/mcp/server/session.py473 +474 +475 | |
async
+
+
+send_tool_list_changed() -> None
+Send a tool list changed notification.
+ + +src/mcp/server/session.py477 +478 +479 | |
async
+
+
+send_prompt_list_changed() -> None
+Send a prompt list changed notification.
+ + +src/mcp/server/session.py481 +482 +483 | |
async
+
+
+send_elicit_complete(
+ elicitation_id: str,
+ related_request_id: RequestId | None = None,
+) -> None
+Send an elicitation completion notification.
+This should be sent when a URL mode elicitation has been completed +out-of-band to inform the client that it may retry any requests +that were waiting for this elicitation.
+ + +Parameters:
+| Name | +Type | +Description | +Default | +
|---|---|---|---|
+ elicitation_id
+ |
+
+ str
+ |
+
+
+
+ The unique identifier of the completed elicitation + |
+ + required + | +
+ related_request_id
+ |
+
+ RequestId | None
+ |
+
+
+
+ Optional ID of the request that triggered this + |
+
+ None
+ |
+
src/mcp/server/session.py485 +486 +487 +488 +489 +490 +491 +492 +493 +494 +495 +496 +497 +498 +499 +500 +501 +502 +503 +504 +505 +506 +507 | |
async
+
+
+send_message(message: SessionMessage) -> None
+Send a raw session message.
+This is primarily used by TaskResultHandler to deliver queued messages +(elicitation/sampling requests) to the client during task execution.
+WARNING: This is a low-level experimental method that may change without +notice. Prefer using higher-level methods like send_notification() or +send_request() for normal operations.
+ + +Parameters:
+| Name | +Type | +Description | +Default | +
|---|---|---|---|
+ message
+ |
+
+ SessionMessage
+ |
+
+
+
+ The session message to send + |
+ + required + | +
src/mcp/server/session.py669 +670 +671 +672 +673 +674 +675 +676 +677 +678 +679 +680 +681 +682 | |
async
+
+
+Server transport for stdio: this communicates with an MCP client by reading +from the current process' stdin and writing to stdout.
+ + +src/mcp/server/stdio.py33 +34 +35 +36 +37 +38 +39 +40 +41 +42 +43 +44 +45 +46 +47 +48 +49 +50 +51 +52 +53 +54 +55 +56 +57 +58 +59 +60 +61 +62 +63 +64 +65 +66 +67 +68 +69 +70 +71 +72 +73 +74 +75 +76 +77 +78 +79 +80 +81 +82 +83 +84 +85 +86 +87 +88 | |
+ Bases: Exception
Exception type raised when an error arrives over an MCP connection.
+ + + + + + + + +src/mcp/shared/exceptions.py8 + 9 +10 +11 +12 +13 +14 +15 +16 +17 +18 | |
__init__(error: ErrorData)
+Initialize McpError.
+ + +src/mcp/shared/exceptions.py15 +16 +17 +18 | |
+ Bases: McpError
Specialized error for when a tool requires URL mode elicitation(s) before proceeding.
+Servers can raise this error from tool handlers to indicate that the client +must complete one or more URL elicitations before the request can be processed.
+ + +raise UrlElicitationRequiredError([ + ElicitRequestURLParams( + mode="url", + message="Authorization required for your files", + url="https://example.com/oauth/authorize", + elicitationId="auth-001" + ) +])
+src/mcp/shared/exceptions.py21 +22 +23 +24 +25 +26 +27 +28 +29 +30 +31 +32 +33 +34 +35 +36 +37 +38 +39 +40 +41 +42 +43 +44 +45 +46 +47 +48 +49 +50 +51 +52 +53 +54 +55 +56 +57 +58 +59 +60 +61 +62 +63 +64 +65 +66 +67 +68 +69 +70 +71 | |
Initialize UrlElicitationRequiredError.
+ + +src/mcp/shared/exceptions.py39 +40 +41 +42 +43 +44 +45 +46 +47 +48 +49 +50 +51 +52 +53 +54 +55 | |
property
+
+
+elicitations: list[ElicitRequestURLParams]
+The list of URL elicitations required before the request can proceed.
+ +classmethod
+
+
+from_error(error: ErrorData) -> UrlElicitationRequiredError
+Reconstruct from an ErrorData received over the wire.
+ + +src/mcp/shared/exceptions.py62 +63 +64 +65 +66 +67 +68 +69 +70 +71 | |
+ Bases: Request[CallToolRequestParams, Literal['tools/call']]
Used by the client to invoke a tool provided by the server.
+ + + + + + + + +src/mcp/types.py1356 +1357 +1358 +1359 +1360 | |
+ Bases: BaseModel
Capabilities a client may support.
+ + + + + + + + +src/mcp/types.py417 +418 +419 +420 +421 +422 +423 +424 +425 +426 +427 +428 +429 +430 +431 +432 +433 +434 | |
class-attribute
+ instance-attribute
+
+
+Experimental, non-standard capabilities that the client supports.
+ +class-attribute
+ instance-attribute
+
+
+sampling: SamplingCapability | None = None
+Present if the client supports sampling from an LLM. +Can contain fine-grained capabilities like context and tools support.
+ +class-attribute
+ instance-attribute
+
+
+elicitation: ElicitationCapability | None = None
+Present if the client supports elicitation from the user.
+ +class-attribute
+ instance-attribute
+
+
+roots: RootsCapability | None = None
+Present if the client supports listing roots.
+ +class-attribute
+ instance-attribute
+
+
+tasks: ClientTasksCapability | None = None
+Present if the client supports task-augmented requests.
+ +
+ Bases: Request[CompleteRequestParams, Literal['completion/complete']]
A request from the client to the server, to ask for completion options.
+ + + + + + + + +src/mcp/types.py1645 +1646 +1647 +1648 +1649 | |
+ Bases: Request[CreateMessageRequestParams, Literal['sampling/createMessage']]
A request from the server to sample an LLM via the client.
+ + + + + + + + +src/mcp/types.py1539 +1540 +1541 +1542 +1543 | |
+ Bases: Result
The client's response to a sampling/create_message request from the server.
+This is the backwards-compatible version that returns single content (no arrays). +Used when the request does not include tools.
+ + + + + + + + +src/mcp/types.py1549 +1550 +1551 +1552 +1553 +1554 +1555 +1556 +1557 +1558 +1559 +1560 +1561 +1562 +1563 | |
instance-attribute
+
+
+role: Role
+The role of the message sender (typically 'assistant' for LLM responses).
+ +instance-attribute
+
+
+content: SamplingContent
+Response content. Single content block (text, image, or audio).
+ +instance-attribute
+
+
+model: str
+The name of the model that generated the message.
+ +class-attribute
+ instance-attribute
+
+
+stopReason: StopReason | None = None
+The reason why sampling stopped, if known.
+ +
+ Bases: Result
The client's response to a sampling/create_message request when tools were provided.
+This version supports array content for tool use flows.
+ + + + + + + + +src/mcp/types.py1566 +1567 +1568 +1569 +1570 +1571 +1572 +1573 +1574 +1575 +1576 +1577 +1578 +1579 +1580 +1581 +1582 +1583 +1584 +1585 +1586 +1587 +1588 +1589 +1590 +1591 | |
instance-attribute
+
+
+role: Role
+The role of the message sender (typically 'assistant' for LLM responses).
+ +instance-attribute
+
+
+content: (
+ SamplingMessageContentBlock
+ | list[SamplingMessageContentBlock]
+)
+Response content. May be a single content block or an array. +May include ToolUseContent if stopReason is 'toolUse'.
+ +instance-attribute
+
+
+model: str
+The name of the model that generated the message.
+ +class-attribute
+ instance-attribute
+
+
+stopReason: StopReason | None = None
+The reason why sampling stopped, if known. +'toolUse' indicates the model wants to use a tool.
+ +property
+
+
+content_as_list: list[SamplingMessageContentBlock]
+Returns the content as a list of content blocks, regardless of whether +it was originally a single block or a list.
+ +
+ Bases: BaseModel
Error information for JSON-RPC error responses.
+ + + + + + + + +src/mcp/types.py193 +194 +195 +196 +197 +198 +199 +200 +201 +202 +203 +204 +205 +206 +207 +208 +209 +210 +211 | |
instance-attribute
+
+
+code: int
+The error type that occurred.
+ +instance-attribute
+
+
+message: str
+A short description of the error. The message SHOULD be limited to a concise single +sentence.
+ +class-attribute
+ instance-attribute
+
+
+data: Any | None = None
+Additional information about the error. The value of this member is defined by the +sender (e.g. detailed error information, nested errors etc.).
+ +
+ Bases: Request[GetPromptRequestParams, Literal['prompts/get']]
Used by the client to get a prompt provided by the server.
+ + + + + + + + +src/mcp/types.py1019 +1020 +1021 +1022 +1023 | |
+ Bases: Result
The server's response to a prompts/get request from the client.
+ + + + + + + + +src/mcp/types.py1221 +1222 +1223 +1224 +1225 +1226 | |
class-attribute
+ instance-attribute
+
+
+description: str | None = None
+An optional description for the prompt.
+ +
+ Bases: BaseMetadata
Describes the name and version of an MCP implementation.
+ + + + + + + + +src/mcp/types.py263 +264 +265 +266 +267 +268 +269 +270 +271 +272 +273 +274 | |
class-attribute
+ instance-attribute
+
+
+websiteUrl: str | None = None
+An optional URL of the website for this implementation.
+ +class-attribute
+ instance-attribute
+
+
+icons: list[Icon] | None = None
+An optional list of icons for this implementation.
+ +
+ Bases: Notification[NotificationParams | None, Literal['notifications/initialized']]
This notification is sent from the client to the server after initialization has +finished.
+ + + + + + + + +src/mcp/types.py702 +703 +704 +705 +706 +707 +708 +709 | |
+ Bases: Request[InitializeRequestParams, Literal['initialize']]
This request is sent from the client to the server when it first connects, asking it +to begin initialization.
+ + + + + + + + +src/mcp/types.py681 +682 +683 +684 +685 +686 +687 +688 | |
+ Bases: Result
After receiving an initialize request from the client, the server sends this.
+ + + + + + + + +src/mcp/types.py691 +692 +693 +694 +695 +696 +697 +698 +699 | |
instance-attribute
+
+
+The version of the Model Context Protocol that the server wants to use.
+ +class-attribute
+ instance-attribute
+
+
+instructions: str | None = None
+Instructions describing how to use the server and its features.
+ +
+ Bases: BaseModel
A response to a request that indicates an error occurred.
+ + + + + + + + +src/mcp/types.py214 +215 +216 +217 +218 +219 +220 | |
+ Bases: Request[dict[str, Any] | None, str]
A request that expects a response.
+ + + + + + + + +src/mcp/types.py152 +153 +154 +155 +156 +157 +158 | |
+ Bases: BaseModel
A successful (non-error) response to a request.
+ + + + + + + + +src/mcp/types.py168 +169 +170 +171 +172 +173 +174 | |
+ Bases: PaginatedRequest[Literal['prompts/list']]
Sent from the client to request a list of prompts and prompt templates.
+ + + + + + + + +src/mcp/types.py968 +969 +970 +971 | |
+ Bases: PaginatedResult
The server's response to a prompts/list request from the client.
+ + + + + + + + +src/mcp/types.py1003 +1004 +1005 +1006 | |
+ Bases: PaginatedRequest[Literal['resources/list']]
Sent from the client to request a list of resources the server has.
+ + + + + + + + +src/mcp/types.py755 +756 +757 +758 | |
+ Bases: PaginatedResult
The server's response to a resources/list request from the client.
+ + + + + + + + +src/mcp/types.py820 +821 +822 +823 | |
+ Bases: PaginatedResult
The server's response to a tools/list request from the client.
+ + + + + + + + +src/mcp/types.py1342 +1343 +1344 +1345 | |
+ Bases: Notification[LoggingMessageNotificationParams, Literal['notifications/message']]
Notification of a log message passed from server to client.
+ + + + + + + + +src/mcp/types.py1415 +1416 +1417 +1418 +1419 | |
+ Bases: BaseModel, Generic[NotificationParamsT, MethodT]
Base class for JSON-RPC notifications.
+ + + + + + + + +src/mcp/types.py125 +126 +127 +128 +129 +130 | |
+ Bases: Request[RequestParams | None, Literal['ping']]
A ping, issued by either the server or the client, to check that the other party is +still alive.
+ + + + + + + + +src/mcp/types.py712 +713 +714 +715 +716 +717 +718 +719 | |
+ Bases: Notification[ProgressNotificationParams, Literal['notifications/progress']]
An out-of-band notification used to inform the receiver of a progress update for a +long-running request.
+ + + + + + + + +src/mcp/types.py745 +746 +747 +748 +749 +750 +751 +752 | |
+ Bases: BaseModel
Capability for prompts operations.
+ + + + + + + + +src/mcp/types.py437 +438 +439 +440 +441 +442 | |
class-attribute
+ instance-attribute
+
+
+listChanged: bool | None = None
+Whether this server supports notifications for changes to the prompt list.
+ +
+ Bases: Request[ReadResourceRequestParams, Literal['resources/read']]
Sent from the client to the server, to read a specific resource URI.
+ + + + + + + + +src/mcp/types.py849 +850 +851 +852 +853 | |
+ Bases: Result
The server's response to a resources/read request from the client.
+ + + + + + + + +src/mcp/types.py888 +889 +890 +891 | |
+ Bases: BaseMetadata
A known resource that the server is capable of reading.
+ + + + + + + + +src/mcp/types.py767 +768 +769 +770 +771 +772 +773 +774 +775 +776 +777 +778 +779 +780 +781 +782 +783 +784 +785 +786 +787 +788 +789 +790 +791 | |
instance-attribute
+
+
+uri: Annotated[AnyUrl, UrlConstraints(host_required=False)]
+The URI of this resource.
+ +class-attribute
+ instance-attribute
+
+
+description: str | None = None
+A description of what this resource represents.
+ +class-attribute
+ instance-attribute
+
+
+mimeType: str | None = None
+The MIME type of this resource, if known.
+ +class-attribute
+ instance-attribute
+
+
+size: int | None = None
+The size of the raw resource content, in bytes (i.e., before base64 encoding +or any tokenization), if known.
+This can be used by Hosts to display file sizes and estimate context window usage.
+ +class-attribute
+ instance-attribute
+
+
+icons: list[Icon] | None = None
+An optional list of icons for this resource.
+ +class-attribute
+ instance-attribute
+
+
+See MCP specification +for notes on _meta usage.
+ +
+ Bases: BaseModel
Capability for resources operations.
+ + + + + + + + +src/mcp/types.py445 +446 +447 +448 +449 +450 +451 +452 | |
class-attribute
+ instance-attribute
+
+
+subscribe: bool | None = None
+Whether this server supports subscribing to resource updates.
+ +class-attribute
+ instance-attribute
+
+
+listChanged: bool | None = None
+Whether this server supports notifications for changes to the resource list.
+ +
+ Bases: Notification[ResourceUpdatedNotificationParams, Literal['notifications/resources/updated']]
A notification from the server to the client, informing it that a resource has +changed and may need to be read again.
+ + + + + + + + +src/mcp/types.py956 +957 +958 +959 +960 +961 +962 +963 +964 +965 | |
+ Bases: BaseModel
Capability for root operations.
+ + + + + + + + +src/mcp/types.py277 +278 +279 +280 +281 +282 | |
class-attribute
+ instance-attribute
+
+
+listChanged: bool | None = None
+Whether the client supports notifications for changes to the roots list.
+ +
+ Bases: BaseModel
Sampling capability structure, allowing fine-grained capability advertisement.
+ + + + + + + + +src/mcp/types.py334 +335 +336 +337 +338 +339 +340 +341 +342 +343 +344 +345 +346 +347 +348 +349 | |
class-attribute
+ instance-attribute
+
+
+context: SamplingContextCapability | None = None
+Present if the client supports non-'none' values for includeContext parameter. +SOFT-DEPRECATED: New implementations should use tools parameter instead.
+ +class-attribute
+ instance-attribute
+
+
+tools: SamplingToolsCapability | None = None
+Present if the client supports tools and toolChoice parameters in sampling requests. +Presence indicates full tool calling support during sampling.
+ +module-attribute
+
+
+SamplingContent: TypeAlias = (
+ TextContent | ImageContent | AudioContent
+)
+Basic content types for sampling responses (without tool use). +Used for backwards-compatible CreateMessageResult when tools are not used.
+ +
+ Bases: BaseModel
Capability for context inclusion during sampling.
+Indicates support for non-'none' values in the includeContext parameter. +SOFT-DEPRECATED: New implementations should use tools parameter instead.
+ + + + + + + + +src/mcp/types.py285 +286 +287 +288 +289 +290 +291 +292 +293 | |
+ Bases: BaseModel
Describes a message issued to or received from an LLM API.
+ + + + + + + + +src/mcp/types.py1154 +1155 +1156 +1157 +1158 +1159 +1160 +1161 +1162 +1163 +1164 +1165 +1166 +1167 +1168 +1169 +1170 +1171 +1172 +1173 +1174 | |
instance-attribute
+
+
+content: (
+ SamplingMessageContentBlock
+ | list[SamplingMessageContentBlock]
+)
+Message content. Can be a single content block or an array of content blocks +for multi-modal messages and tool interactions.
+ +class-attribute
+ instance-attribute
+
+
+See MCP specification +for notes on _meta usage.
+ +property
+
+
+content_as_list: list[SamplingMessageContentBlock]
+Returns the content as a list of content blocks, regardless of whether +it was originally a single block or a list.
+ +module-attribute
+
+
+SamplingMessageContentBlock: TypeAlias = (
+ TextContent
+ | ImageContent
+ | AudioContent
+ | ToolUseContent
+ | ToolResultContent
+)
+Content block types allowed in sampling messages.
+ +
+ Bases: BaseModel
Capability indicating support for tool calling during sampling.
+When present in ClientCapabilities.sampling, indicates that the client +supports the tools and toolChoice parameters in sampling requests.
+ + + + + + + + +src/mcp/types.py296 +297 +298 +299 +300 +301 +302 +303 +304 | |
+ Bases: BaseModel
Capabilities that a server may support.
+ + + + + + + + +src/mcp/types.py506 +507 +508 +509 +510 +511 +512 +513 +514 +515 +516 +517 +518 +519 +520 +521 +522 +523 | |
class-attribute
+ instance-attribute
+
+
+Experimental, non-standard capabilities that the server supports.
+ +class-attribute
+ instance-attribute
+
+
+logging: LoggingCapability | None = None
+Present if the server supports sending log messages to the client.
+ +class-attribute
+ instance-attribute
+
+
+prompts: PromptsCapability | None = None
+Present if the server offers any prompt templates.
+ +class-attribute
+ instance-attribute
+
+
+resources: ResourcesCapability | None = None
+Present if the server offers any resources to read.
+ +class-attribute
+ instance-attribute
+
+
+tools: ToolsCapability | None = None
+Present if the server offers any tools to call.
+ +class-attribute
+ instance-attribute
+
+
+completions: CompletionsCapability | None = None
+Present if the server offers autocompletion suggestions for prompts and resources.
+ +class-attribute
+ instance-attribute
+
+
+tasks: ServerTasksCapability | None = None
+Present if the server supports task-augmented requests.
+ +
+ Bases: Request[SetLevelRequestParams, Literal['logging/setLevel']]
A request from the client to the server, to enable or adjust logging.
+ + + + + + + + +src/mcp/types.py1393 +1394 +1395 +1396 +1397 | |
+ Bases: Request[SubscribeRequestParams, Literal['resources/subscribe']]
Sent from the client to request resources/updated notifications from the server +whenever a particular resource changes.
+ + + + + + + + +src/mcp/types.py917 +918 +919 +920 +921 +922 +923 +924 | |
+ Bases: BaseMetadata
Definition for a tool the client can call.
+ + + + + + + + +src/mcp/types.py1315 +1316 +1317 +1318 +1319 +1320 +1321 +1322 +1323 +1324 +1325 +1326 +1327 +1328 +1329 +1330 +1331 +1332 +1333 +1334 +1335 +1336 +1337 +1338 +1339 | |
class-attribute
+ instance-attribute
+
+
+description: str | None = None
+A human-readable description of the tool.
+ +instance-attribute
+
+
+A JSON Schema object defining the expected parameters for the tool.
+ +class-attribute
+ instance-attribute
+
+
+An optional JSON Schema object defining the structure of the tool's output +returned in the structuredContent field of a CallToolResult.
+ +class-attribute
+ instance-attribute
+
+
+icons: list[Icon] | None = None
+An optional list of icons for this tool.
+ +class-attribute
+ instance-attribute
+
+
+annotations: ToolAnnotations | None = None
+Optional additional tool information.
+ +class-attribute
+ instance-attribute
+
+
+See MCP specification +for notes on _meta usage.
+ +
+ Bases: BaseModel
Controls tool usage behavior during sampling.
+Allows the server to specify whether and how the LLM should use tools +in its response.
+ + + + + + + + +src/mcp/types.py1485 +1486 +1487 +1488 +1489 +1490 +1491 +1492 +1493 +1494 +1495 +1496 +1497 +1498 +1499 +1500 +1501 | |
class-attribute
+ instance-attribute
+
+
+mode: Literal['auto', 'required', 'none'] | None = None
+Controls when tools are used: +- "auto": Model decides whether to use tools (default) +- "required": Model MUST use at least one tool before completing +- "none": Model should not use tools
+ +
+ Bases: BaseModel
Content representing the result of a tool execution.
+This content type appears in user messages as a response to a ToolUseContent +from the assistant. It contains the output of executing the requested tool.
+ + + + + + + + +src/mcp/types.py1110 +1111 +1112 +1113 +1114 +1115 +1116 +1117 +1118 +1119 +1120 +1121 +1122 +1123 +1124 +1125 +1126 +1127 +1128 +1129 +1130 +1131 +1132 +1133 +1134 +1135 +1136 +1137 +1138 +1139 +1140 +1141 +1142 +1143 | |
instance-attribute
+
+
+type: Literal['tool_result']
+Discriminator for tool result content.
+ +instance-attribute
+
+
+toolUseId: str
+The unique identifier that corresponds to the tool call's id field.
+ +class-attribute
+ instance-attribute
+
+
+content: list[ContentBlock] = []
+A list of content objects representing the tool result. +Defaults to empty list if not provided.
+ +class-attribute
+ instance-attribute
+
+
+Optional structured tool output that matches the tool's outputSchema (if defined).
+ +class-attribute
+ instance-attribute
+
+
+isError: bool | None = None
+Whether the tool execution resulted in an error.
+ +class-attribute
+ instance-attribute
+
+
+See MCP specification +for notes on _meta usage.
+ +
+ Bases: BaseModel
Capability for tools operations.
+ + + + + + + + +src/mcp/types.py455 +456 +457 +458 +459 +460 | |
class-attribute
+ instance-attribute
+
+
+listChanged: bool | None = None
+Whether this server supports notifications for changes to the tool list.
+ +
+ Bases: BaseModel
Content representing an assistant's request to invoke a tool.
+This content type appears in assistant messages when the LLM wants to call a tool +during sampling. The server should execute the tool and return a ToolResultContent +in the next user message.
+ + + + + + + + +src/mcp/types.py1081 +1082 +1083 +1084 +1085 +1086 +1087 +1088 +1089 +1090 +1091 +1092 +1093 +1094 +1095 +1096 +1097 +1098 +1099 +1100 +1101 +1102 +1103 +1104 +1105 +1106 +1107 | |
instance-attribute
+
+
+type: Literal['tool_use']
+Discriminator for tool use content.
+ +instance-attribute
+
+
+name: str
+The name of the tool to invoke. Must match a tool name from the request's tools array.
+ +instance-attribute
+
+
+id: str
+Unique identifier for this tool call, used to correlate with ToolResultContent.
+ +instance-attribute
+
+
+Arguments to pass to the tool. Must conform to the tool's inputSchema.
+ +class-attribute
+ instance-attribute
+
+
+See MCP specification +for notes on _meta usage.
+ +
+ Bases: Request[UnsubscribeRequestParams, Literal['resources/unsubscribe']]
Sent from the client to request cancellation of resources/updated notifications from +the server.
+ + + + + + + + +src/mcp/types.py935 +936 +937 +938 +939 +940 +941 +942 | |