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Message Types

Complete Type Index

Core Types (7)

Type StringModelDirectionDescription
handshake/reqHandshakeRequestA→HSession initiation
handshake/respHandshakeResponseH→AHandshake result
invoke/eventA2EEventH→AStreaming event
pingPingA→HLiveness check
pongPongH→APing response
shutdownShutdownA→HGraceful termination
errorA2EErrorH→AError response

Tools (5)

Type StringModelDescription
tool/list/reqToolListRequestList available tools
tool/list/respToolListResponseTool list result
tool/call/reqToolCallRequestExecute a tool
tool/call/respToolCallResponseTool execution result
tool/eventToolEventStreaming tool event

Memory (6)

Type StringModelDescription
memory/store/reqMemoryStoreRequestStore memory entries
memory/store/respMemoryStoreResponseStore result
memory/retrieve/reqMemoryRetrieveRequestRetrieve from memory
memory/retrieve/respMemoryRetrieveResponseRetrieved entries
memory/forget/reqMemoryForgetRequestDelete from memory
memory/forget/respMemoryForgetResponseDeletion count

Environment (14)

Type StringModelDescription
env/reset/reqEnvResetRequestReset environment
env/reset/respEnvResetResponseReset result
env/step/reqEnvStepRequestTake a step
env/step/respEnvStepResponseStep result
env/observe/reqEnvObserveRequestObserve state
env/observe/respEnvObserveResponseObservation
env/close/reqEnvCloseRequestClose environment
env/close/respEnvCloseResponseClose result
env/spaces/reqEnvSpacesRequestGet action/state spaces
env/spaces/respEnvSpacesResponseSpace schemas
env/render/reqEnvRenderRequestRender environment
env/render/respEnvRenderResponseRendered output
env/plan/reqEnvPlanRequestGet affordances
env/plan/respEnvPlanResponseSuggested actions
env/batch_step/reqEnvBatchStepRequestParallel steps
env/batch_step/respEnvBatchStepResponseBatch results
env/state_pushEnvStatePushServer-initiated push

Processes (8)

Type StringModelDescription
proc/spawn/reqProcSpawnRequestStart a process
proc/spawn/respProcSpawnResponseSpawn result
proc/write/reqProcWriteRequestWrite to stdin
proc/write/respProcWriteResponseWrite result
proc/read/eventProcReadEventStdout/stderr output
proc/kill/reqProcKillRequestKill process
proc/kill/respProcKillResponseKill result
proc/status/reqProcStatusRequestQuery status
proc/status/respProcStatusResponseStatus info

Learning (8)

Type StringModelDescription
learn/feedback/reqLearnFeedbackRequestSubmit feedback
learn/feedback/respLearnFeedbackResponseFeedback result
learn/experience/reqLearnExperienceRequestRecord RL experience
learn/experience/respLearnExperienceResponseExperience stored
learn/adapt/reqLearnAdaptRequestTrigger adaptation
learn/adapt/respLearnAdaptResponseAdapted records
learn/stats/reqLearnStatsRequestQuery stats
learn/stats/respLearnStatsResponsePerformance data

Skills (5)

Type StringModelDescription
skill/discover/reqSkillDiscoverRequestDiscover skills
skill/discover/respSkillDiscoverResponseSkill list
skill/call/reqSkillCallRequestExecute a skill
skill/call/respSkillCallResponseSkill result
skill/eventSkillEventStreaming skill event

Toolkits (4)

Type StringModelDescription
toolkit/list/reqToolkitListRequestList toolkits
toolkit/list/respToolkitListResponseToolkit list
toolkit/configure/reqToolkitConfigureRequestConfigure a toolkit
toolkit/configure/respToolkitConfigureResponseConfiguration result

Chains (3)

Type StringModelDescription
chain/reqChainRequestExecute a chain DAG
chain/respChainResponseChain result
chain/eventChainEventNode execution event

MCP (19)

Type StringDescription
mcp/server/register/reqRegister MCP server
mcp/server/register/respRegistration result
mcp/server/list/reqList MCP servers
mcp/server/list/respServer list
mcp/server/unregister/reqUnregister server
mcp/server/unregister/respUnregister result
mcp/server/pushServer-initiated notification
mcp/resource/list/reqList resources
mcp/resource/list/respResource list
mcp/resource/read/reqRead a resource
mcp/resource/read/respResource content
mcp/resource/subscribe/reqSubscribe to resource
mcp/resource/subscribe/respSubscription result
mcp/prompt/list/reqList prompts
mcp/prompt/list/respPrompt list
mcp/prompt/get/reqGet a prompt
mcp/prompt/get/respPrompt content
mcp/sampling/reqLLM sampling request (server→agent)
mcp/sampling/respLLM sampling response (agent→server)

Total: 79 message types across 10 namespaces

A2E Protocol v1.0 — Released under the MIT License.