Agent reason: an agent should never have to guess what follows a call. One
place (call_tool, after the tool answers) now gives every tool result the
same four fields: next_steps (what to do next, each with why and whether it
is required), guards (the named refusal and the tool that remedies it),
warnings, and, on any tool that is not read-only, head (where the journal
ends after the call's last write). A tool's own field of the same name is
kept, never overwritten; the text block says what the structured content
says.
Next steps come from the tool's own result (a preview gets its confirm step
with the digest; a post is followed by showing the entry and, only if it
was in error, its reversal; a draft by its lines; a statement by marking
its lines and reconciling; a period list by the close) and, after a change
to an entry or an invoice, from the viewer's own Needs-attention items about
that subject, so the agent and the human read one list.
guards.rs is the registry of refusals (stale_preview,
format_upgrade_pending, receipt_required, approval_required, party_shares,
party_required, open_drafts, untagged_control_line, duplicate_vendor_ref,
first_number_locked), each naming a tool that exists. A refusal whose text
carries a guard gets it as structuredContent.guards; its text is unchanged.
Tests: every_mutating_result_has_head_and_next_steps (the whole router),
the_envelope_keeps_what_a_tool_said_and_carries_a_refusal_guard,
every_guard_names_an_existing_tool, a_refusal_becomes_its_guard,
every_step_a_tool_names_exists.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HS8WZziDnyxunC23MUxrLp
swaitsandClaude Fable 5.1
cf73d0bda5