II.
MCPTransport overview
Reference · livemcp-transport:stdio
stdio overview
Inspect the raw attributes, linked wiki pages, and inbound or outbound graph edges for mcp-transport:stdio.
Attributes
displayName
stdio
kind
stdio
specVersion
2024-11-05
currentSpecRevision
2025-11-25
specRevisions
- 2024-11-05
- 2025-03-26
- 2025-06-18
- 2025-11-25
status
live
streaming
partial
specUrl
connectionLifecycle
Lifecycle is bound to the child-process lifetime:
1. Host spawns the server as a subprocess; stdin/stdout become the
JSON-RPC channel (stderr is reserved for human-readable logs).
2. Client sends `initialize` (request) with `protocolVersion`,
`clientInfo`, and `capabilities`.
3. Server responds with its own `protocolVersion`, `serverInfo`,
and `capabilities`.
4. Client sends `notifications/initialized`. Session is now ready.
5. Shutdown is signalled by closing stdin (EOF). Server is expected
to exit cleanly; host may follow up with SIGTERM / SIGKILL.
capabilityNegotiation
`initialize` request:
{ "jsonrpc": "2.0", "id": 1, "method": "initialize",
"params": { "protocolVersion": "<spec-rev>",
"clientInfo": { "name": "...", "version": "..." },
"capabilities": { "roots"?: {...}, "sampling"?: {...},
"elicitation"?: {...} } } }
`initialize` response:
{ "jsonrpc": "2.0", "id": 1,
"result": { "protocolVersion": "<spec-rev>",
"serverInfo": { "name": "...", "version": "..." },
"capabilities": { "tools"?: {...}, "resources"?: {...},
"prompts"?: {...}, "logging"?: {...} },
"instructions"?: "..." } }
notificationModel
Standard JSON-RPC 2.0 notifications (no `id` field). Server pushes
notifications inline on stdout interleaved with responses; client
demultiplexes by presence-or-absence of `id`. Examples:
`notifications/tools/list_changed`, `notifications/resources/updated`,
`notifications/progress`, `notifications/message` (logging).
reconnectPolicy
No reconnect — stdio sessions are tied 1:1 to the subprocess. Loss
of the child process is terminal; the host must respawn and run a
fresh `initialize` handshake. No session-resumption identifier.
authentication
None at the transport layer. The host process inherits the security
boundary of the spawning user; any per-server credentials are passed
via environment variables / argv / config files outside the JSON-RPC
channel itself.
streamingFraming
Newline-delimited JSON (NDJSON): each JSON-RPC message is exactly one
line on stdout/stdin terminated by `\n`; no embedded newlines in the
payload. Logs and free-form output go on stderr to keep the JSON-RPC
channel clean. Message-id discipline is standard JSON-RPC: requests
carry a unique `id` (string or integer); responses echo it; notifications
omit it. The 2025-06-18 spec revision removed JSON-RPC batch arrays.
Outgoing edges
spoken_by20
- agent-runtime-impl:a5c.runtime@current·AgentRuntimeImpla5c Unified Runtime (current) — unified tool host
- agent-runtime-impl:amp.runtime@current·AgentRuntimeImplSourcegraph Amp Runtime (current)
- agent-runtime-impl:agent-platform.runtime@current·AgentRuntimeImplagent-platform Runtime (current) — SDK runtime + daemon
- agent-runtime-impl:babysitter.runtime@current·AgentRuntimeImplbabysitter Runtime (current) — task-effect dispatcher + harness adapters
- agent-runtime-impl:babysitter-sdk.runtime@current·AgentRuntimeImplbabysitter SDK Runtime (current) — task-effect dispatcher
- agent-runtime-impl:claude-agent-sdk.runtime@current·AgentRuntimeImplClaude Agent SDK Runtime (current)
- agent-runtime-impl:claude-code.runtime@1.x·AgentRuntimeImplClaude Code Runtime (1.x)
- agent-runtime-impl:codex-app-server.runtime@current·AgentRuntimeImplCodex App-Server Runtime (current)
- agent-runtime-impl:codex.runtime@1.x·AgentRuntimeImplCodex CLI Runtime (1.x)
- agent-runtime-impl:codex-sdk.runtime@current·AgentRuntimeImplCodex SDK Runtime (current)
- agent-runtime-impl:copilot-cli.runtime@current·AgentRuntimeImplGitHub Copilot CLI Runtime (current)
- agent-runtime-impl:cursor.runtime@current·AgentRuntimeImplCursor Runtime (current)
- agent-runtime-impl:droid.runtime@current·AgentRuntimeImplFactory Droid Runtime (current)
- agent-runtime-impl:gemini-cli.runtime@current·AgentRuntimeImplGemini CLI Runtime (current)
- agent-runtime-impl:hermes.runtime@current·AgentRuntimeImplHermes Runtime (current)
- agent-runtime-impl:omp.runtime@current·AgentRuntimeImplOMP Runtime (current)
- agent-runtime-impl:openclaw.runtime@current·AgentRuntimeImplOpenClaw Runtime (current)
- agent-runtime-impl:opencode.runtime@1.x·AgentRuntimeImplOpenCode Runtime (1.x)
- agent-runtime-impl:pi.runtime@current·AgentRuntimeImplPi Runtime (current)
- agent-runtime-impl:qwen.runtime@current·AgentRuntimeImplQwen Code Runtime (current)
Incoming edges
connects23
- agent-runtime-impl:a5c.runtime@current·AgentRuntimeImpla5c Unified Runtime (current) — unified tool host
- agent-runtime-impl:agent-platform.runtime@current·AgentRuntimeImplagent-platform Runtime (current) — SDK runtime + daemon
- agent-runtime-impl:amp.runtime@current·AgentRuntimeImplSourcegraph Amp Runtime (current)
- agent-runtime-impl:antigravity-cli.runtime@current·AgentRuntimeImplAntigravity CLI Runtime (current)
- agent-runtime-impl:babysitter.runtime@current·AgentRuntimeImplbabysitter Runtime (current) — task-effect dispatcher + harness adapters
- agent-runtime-impl:babysitter-sdk.runtime@current·AgentRuntimeImplbabysitter SDK Runtime (current) — task-effect dispatcher
- agent-runtime-impl:claude-agent-sdk.runtime@current·AgentRuntimeImplClaude Agent SDK Runtime (current)
- agent-runtime-impl:claude-code.runtime@1.x·AgentRuntimeImplClaude Code Runtime (1.x)
- agent-runtime-impl:codex-app-server.runtime@current·AgentRuntimeImplCodex App-Server Runtime (current)
- agent-runtime-impl:codex.runtime@1.x·AgentRuntimeImplCodex CLI Runtime (1.x)
- agent-runtime-impl:codex-sdk.runtime@current·AgentRuntimeImplCodex SDK Runtime (current)
- agent-runtime-impl:copilot-cli.runtime@current·AgentRuntimeImplGitHub Copilot CLI Runtime (current)
- agent-runtime-impl:cursor.runtime@current·AgentRuntimeImplCursor Runtime (current)
- agent-runtime-impl:droid.runtime@current·AgentRuntimeImplFactory Droid Runtime (current)
- agent-runtime-impl:gemini-cli.runtime@current·AgentRuntimeImplGemini CLI Runtime (current)
- agent-runtime-impl:genty.runtime@current·AgentRuntimeImplgenty Runtime (current) — composed agent-runtime + SDK runtime
- agent-runtime-impl:hermes.runtime@current·AgentRuntimeImplHermes Runtime (current)
- agent-runtime-impl:omp.runtime@current·AgentRuntimeImplOMP Runtime (current)
- agent-runtime-impl:openclaw.runtime@current·AgentRuntimeImplOpenClaw Runtime (current)
- agent-runtime-impl:opencode.runtime@1.x·AgentRuntimeImplOpenCode Runtime (1.x)
- agent-runtime-impl:pi.runtime@current·AgentRuntimeImplPi Runtime (current)
- agent-runtime-impl:pikiclaw.runtime@current·AgentRuntimeImplPikiClaw Runtime (current)
- agent-runtime-impl:qwen.runtime@current·AgentRuntimeImplQwen Code Runtime (current)
speaks23
- agent-runtime-impl:a5c.runtime@current·AgentRuntimeImpla5c Unified Runtime (current) — unified tool host
- agent-runtime-impl:agent-platform.runtime@current·AgentRuntimeImplagent-platform Runtime (current) — SDK runtime + daemon
- agent-runtime-impl:amp.runtime@current·AgentRuntimeImplSourcegraph Amp Runtime (current)
- agent-runtime-impl:antigravity-cli.runtime@current·AgentRuntimeImplAntigravity CLI Runtime (current)
- agent-runtime-impl:babysitter.runtime@current·AgentRuntimeImplbabysitter Runtime (current) — task-effect dispatcher + harness adapters
- agent-runtime-impl:babysitter-sdk.runtime@current·AgentRuntimeImplbabysitter SDK Runtime (current) — task-effect dispatcher
- agent-runtime-impl:claude-agent-sdk.runtime@current·AgentRuntimeImplClaude Agent SDK Runtime (current)
- agent-runtime-impl:claude-code.runtime@1.x·AgentRuntimeImplClaude Code Runtime (1.x)
- agent-runtime-impl:codex-app-server.runtime@current·AgentRuntimeImplCodex App-Server Runtime (current)
- agent-runtime-impl:codex.runtime@1.x·AgentRuntimeImplCodex CLI Runtime (1.x)
- agent-runtime-impl:codex-sdk.runtime@current·AgentRuntimeImplCodex SDK Runtime (current)
- agent-runtime-impl:copilot-cli.runtime@current·AgentRuntimeImplGitHub Copilot CLI Runtime (current)
- agent-runtime-impl:cursor.runtime@current·AgentRuntimeImplCursor Runtime (current)
- agent-runtime-impl:droid.runtime@current·AgentRuntimeImplFactory Droid Runtime (current)
- agent-runtime-impl:gemini-cli.runtime@current·AgentRuntimeImplGemini CLI Runtime (current)
- agent-runtime-impl:genty.runtime@current·AgentRuntimeImplgenty Runtime (current) — composed agent-runtime + SDK runtime
- agent-runtime-impl:hermes.runtime@current·AgentRuntimeImplHermes Runtime (current)
- agent-runtime-impl:omp.runtime@current·AgentRuntimeImplOMP Runtime (current)
- agent-runtime-impl:openclaw.runtime@current·AgentRuntimeImplOpenClaw Runtime (current)
- agent-runtime-impl:opencode.runtime@1.x·AgentRuntimeImplOpenCode Runtime (1.x)
- agent-runtime-impl:pi.runtime@current·AgentRuntimeImplPi Runtime (current)
- agent-runtime-impl:pikiclaw.runtime@current·AgentRuntimeImplPikiClaw Runtime (current)
- agent-runtime-impl:qwen.runtime@current·AgentRuntimeImplQwen Code Runtime (current)