The runtime names the caller it took from the subject a call arrived on in the
call's _meta; stdio.CallerOf(args) hands it to the tool. Never read from the
arguments, and Unproven when the runtime named none, so a bundle on an older
runtime still says, explicitly, that its caller was not proven.
mesh-cli holds no credential: it asks the node-engine on its own machine
over a socket, and the node-engine reads the account from the kernel. The
socket's path, the request and the answer are shared by the program and the
node-engine, so they live here once (ADR 0039: a local protocol a module's
program speaks to its runtime). The bus request the node-engine then makes
is the transport's, and stays out of the SDK.
A handler takes an event by returning and asks for it again by throwing;
any mesh/event answer but an error is taken. Written down in the README
where event handling is, with what follows for a handler: throw only when
the work was not done, and be safe to run twice.
Both SDKs added the handler before asking the runtime and kept it when the
runtime refused, so a module that asks again until it is taken (every Go
consumer does) ran its handler once per attempt for every event. A refused
subscribe now removes its handler; one the Go runtime did not answer in
time is kept, since the runtime may have bound it.
state(name) / stdio.State(name): get, put, delete, keys and watch over the
runtime's mesh/state verbs. A watch's handler is registered under the id it
is asked with, so its current values — which arrive before the watch is
answered — and its changes reach it and no other watch.
Subscribe(pattern, handler) asks the runtime for the module's events and answers each mesh/event
only after the matching handlers returned nil, so the runtime acknowledges it on the bus then and
not before; Ask(key, body) calls a tool as the module. Topic matching is the TypeScript SDK's.
What the TypeScript SDK's stdio loop does, in Go: an empty name serves as MESH_SERVED_MODULE; each
call runs beside the loop so a tool waiting on the runtime does not deadlock it; Emit asks the
runtime (mesh/publish) with the same envelope and headers. README says how to install it and how
releases are tagged.
The node's runtime launches a tools bundle as a process and speaks MCP over stdio to it, so a tool
may be written in any language and the transport stays in the runtime (ADR 0039's refusal, kept).
Each SDK is the loop and the tool type and nothing else: `@novox/mesh-sdk/stdio` (serveStdio, and
serveRegisteredOverStdio for a bundle that already registers the in-process way), python/, go/,
rust/ and c/ beside it, each with an example answering `greet` and the seat verb `node-lamp.on`.
Skeletons, by the operator's direction: the bare minimum one bundle per language needs to be built
and answer, proven here by each example answering tools/list and tools/call on stdio.
jochen
jschoubben