f256f3961d
One principle: every fact in the assembled prompt has exactly one owner.
- dsh-system-prompt: merge-extensible AssembleContext on assemble();
a variable(name, provider) registry; {{name}} interpolation in
renderPrompt, strict (unknown/valueless/malformed references throw);
duplicate section and variable names rejected; assembly carries
resolved section text + variables through the assemble waterfall.
- dsh-agent declares AssembleContext.agent; dsh-agent-loop registers
the agent:persona section (order 0 - identity renders before tool
guidance) and the model/cwd variables, and drops its string join:
renderPrompt(assembly) IS the full prompt.
- Tool guidance moves to its owners: descriptions carry per-tool
semantics; sections only cross-call habits (tool:bash exit-code
habit at order 105; read's not-shell nudge). todo/subagent need no
section - their descriptions already carry the contract.
- SubagentProvider.inheritsParentContext (spawn/acp false, fork true);
dsh-tool-subagent derives truthful per-provider wording and resolves
the provider at load (backend must be listed first).
- Example personas shrink to identity + behavior with {{model}} (and
{{cwd}} in the ACP tree); the welcome banner stops enumerating tools.
RFC: docs/rfc/implemented/architecture/2026-07-05-prompt-variables-and-tool-guidance-ownership.md
fs/ - filesystem capability family
The filesystem stack: a provider seam (text IO + atomic mutation with an optional version guard), a local implementation, a policy gate plugin (observed-state + read-before-edit + version-guarded write/edit), and the model-facing file tools + executor. All product packages.
| Package | Role | ctx key |
|---|---|---|
fs/ |
Provider seam: text IO + atomic mutation primitives (optional version guard); owns the fs/* policy events |
ctx.fs |
fs-local/ |
Local-filesystem FileSystem implementation |
(registers ctx.fs) |
fs-policy/ |
Policy gate plugin: observed-state + read-before-edit + version-guarded write/edit, via the fs/* event gate |
(no service — fs/* listeners) |
tool-fs/ |
Model-facing read/write/edit tools AND the executor (reads via ctx.fs, owns read windowing, dispatches fs/*) |
(registers on ctx.tools) |
The interface lives at fs/fs/. A sandboxed, remote, or project-scoped filesystem backend can replace fs-local without touching the seam, the policy gate, or the model-facing tool schemas. The policy (fs-policy/) is a plugin that participates only through the fs/* event gate, not a service the tool injects — so dropping it gracefully loses the policy and leaves the unconstrained bare provider rather than breaking the tool. A deployment that loads tool-fs/ is expected to also load it.