Add optional _meta property bag to RootState#199
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Add an open `_meta: Record<string, unknown>` property to `RootState`, mirroring the existing MCP-style `_meta` convention already used on `SessionState`, messages, tool calls, and `SessionModelInfo`. This gives agent hosts a place to attach implementation-defined metadata about the host for example a well-known `hostBuild` key carrying theitself hosting program's build version/commit/date. Regenerated all client artifacts (Go, Kotlin, Rust, Swift, TypeScript) and JSON schemas, and added CHANGELOG entries to the spec and every client. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
The hand-written `ahp` crate constructs `RootState` literally in several places (host runtime, multi-host state mirror, reducer tests/examples, and doctests) that the code generator does not touch. Add `meta: None` to each so the workspace compiles against the regenerated `ahp-types::RootState`. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Drop the `hostBuild` example and MCP-convention note from the `RootState._meta` doc comment, leaving the generic "Clients MAY look for well-known keys here to provide enhanced UI." Regenerated all client artifacts and schemas. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
lszomoru
approved these changes
Jun 6, 2026
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What
Adds an open
_meta?: Record<string, unknown>property toRootState, mirroring the existing MCP-style_metaconvention already used onSessionState, messages, tool calls, andSessionModelInfo.This gives agent hosts a place to attach implementation-defined metadata about the host itself (as opposed to per-session metadata). The first intended consumer is a well-known
hostBuildkey carrying the hosting program's build information (version, commit, date), so a client can see which build is hosting useful when inspecting the output of a remote agent host.itWhy on
RootStateRootStateis the agent host's own global state, delivered as a snapshot at connect time, so any client reliably receives the metadata as part of the handshake. The protocol itself stays thehostBuildkey is a convention layered on top of the open_metabag, exactly like the existinggitkey onSessionState._meta.genericChanges
types/channels-root/state.ts: add_metatoRootState.npm run generate.## [0.4.0]) and every client's## [Unreleased].Validation
npm test(typecheck + lint +verify:release-metadata+verify:changelog+ reducer tests, 235 passing).(Written by Copilot)