Proposal: stateless, instruction-only host mode for hosted/multi-tenant runtimes #3061

Summary

Proposal: a stateless, instruction-only host mode for agent runtimes that serve gstack skills to many users. In those runtimes there is no gstack install, no ~/.gstack state root, and no local helper binaries. Each user's data has to stay in the runtime's own tenant-scoped storage.

Today a host config can suppress resolvers (PREAMBLE, learnings, aside, brain cache). But many skill bodies still instruct the agent to read and write $GSTACK_STATE_ROOT/projects/..., call bin/gstack-* helpers, log telemetry, or use the Aside agent. On a hosted runtime with file tools, that would put user documents into untracked home-directory state.

Measurements (v1.91.31.0, rendered with a custom render-only host that suppresses those resolvers)

Fenced steps that still use gstack state, helpers or telemetry, plus prose references:

Only investigate stays complete once those steps are removed. To ship office-hours, we maintain a downstream overlay: a reviewed replacement for each affected section, pinned to the upstream section's SHA-256 so drift fails the build. That works, but every overlay is a fork of your text.

Proposal

1. A host capability, e.g. capabilities.state: 'none'. Under it, resolvers that touch state or helpers render a host-provided hook instead of shell steps.

2. A few named hooks, so hosts map one concept instead of rewriting prose:

   • {{ARTIFACT_SAVE:<kind>}} / {{ARTIFACT_FIND:<kind>}} (design docs, plans, reviews, retros)
   • {{WEB_RESEARCH}}
   • {{SECRET_SCAN}} before anything leaves the user's space
   • {{USER_PREF:<key>}} (e.g. founder-resources opt-out)

   The claude host keeps today's exact output.

3. A generator check: a state: 'none' render fails if it still contains ~/.gstack, $GSTACK_, bin/gstack-* or --event-type.

The gbrain resolvers already work this way (GBRAIN_CONTEXT_LOAD / GBRAIN_SAVE_RESULTS are concepts a host can map), so this generalizes an existing pattern.

We're happy to send a PR, starting with office-hours plus the generator check, if this direction works for you.