docs(spec): add helper-instance slice to the agent-runtime spec

The v0 draft covered identity and message targeting for concurrent agents but not spawn mechanics or write-safety for the shared files the session-context split doesn't isolate. I added a section for the motivating case (a second Claude in one project doing lookups and safe task updates): ai --helper spawn with automatic AI_AGENT_ID, a tiered read/write contract where helpers make scoped single-heading org edits and file-wide passes plus all git mutation stay primary-only, light helper startup, and helper wrap-up. Phase 1.5 sequences the slice independently of the runtime-neutral phases 2-6.

1 files changed, 17 insertions, 0 deletions

diff --git a/todo.org b/todo.org
index 1cd298b..bb1c2cb 100644
--- a/todo.org
+++ b/todo.org
@@ -40,6 +40,20 @@ CLOSED: [2026-06-11 Thu]
 
 Cancelled 2026-06-11: Craig confirmed the decision — one todo queue with a single Open Work / Resolved pair. Home reshapes its consolidated file to that form, and the existing single-pair tooling works unmodified. No code change needed.
 
+** TODO [#B] Helper-instance support — concurrent same-project Claude :feature:
+:PROPERTIES:
+:CREATED: [2026-06-11 Thu]
+:LAST_REVIEWED: 2026-06-11
+:END:
+Implement Phase 1.5 of the generic-agent-runtime spec ([[file:docs/design/2026-05-28-generic-agent-runtime-spec.org][spec]], amended 2026-06-11 with the "Concurrent same-project agents" section). Craig's case: spawn a second Claude in the same project to look things up or update tasks safely while the primary works. The session-context split (AI_AGENT_ID + session-context.d/) already shipped; this builds the rest:
+
+- =ai --helper= flag: live-anchor detection, auto AI_AGENT_ID + AI_HELPER export, tmux window naming, warn-and-run-normal when no primary is live.
+- Shared-file read/write contract into protocols.org (helper: scoped single-heading org edits only; file-wide passes, inbox processing, and all git mutation stay primary-only); helper branches in startup.org (light path, no pulls/rsync) and wrap-it-up.org (archive own file, skip hygiene + commit).
+- Bats: launcher id assignment/sanitization, helper-vs-primary resolution, two simultaneous context files.
+- Manual validation with Craig: live helper against a live primary — lookup, one scoped todo.org edit, wrap-up, primary commits the helper's edit cleanly.
+
+Independent of the spec's phases 2-6 (runtime-neutral refactor), which stay gated on their own go/no-go.
+
 ** VERIFY Should new personal projects start as areas inside home rather than standalone ~/projects entries?
 Home's consolidation (2026-06-11) leaves ~/projects with home and work only. The open template question: when Craig starts a new personal project, does =first-session.org= / =install-ai.sh= guidance now say "create an area in home" by default, with standalone reserved for code projects in ~/code? Affects first-session.org, install-ai.sh docs, and the triggers.md "Launch project X" resolution (folded names like "finances" no longer resolve as projects; an area-aware launch could map them to home).
 
@@ -1123,6 +1137,9 @@ Before any implementation: needs a real review pass on the spec, and a decision
 *** 2026-06-10 Wed @ 14:13:55 -0500 Noted Phase 1 already shipped; narrowed scope to the phases 2-6 decision
 Phase 1 (the correctness fix) is live: protocols.org documents the AI_AGENT_ID-scoped session-context path (=.ai/session-context.d/<id>.org=) and =.ai/scripts/session-context-path= resolves it. The singleton race Codex flagged is closed. What remains is the spec review plus a go/no-go on the broader runtime-neutral refactor: runtimes/ adapter manifests, generic install commands, language-bundle split, launcher refactor, local model service.
 
+*** 2026-06-11 Thu @ 19:26:26 -0500 Spec amended with the helper-instance slice; implementation split out
+Craig's motivating case (a second Claude in the same project for lookups and safe task updates) was under-specified in v0 — it had identity and message targeting but no spawn mechanics and no write-safety contract for the shared files the session-context split doesn't isolate. Added the "Concurrent same-project agents (helper instances)" section (subagent boundary, identity/spawn via =ai --helper=, the tiered read/write contract, light startup, helper wrap-up) and Phase 1.5 to the migration plan. Implementation filed as its own [#B] task ("Helper-instance support"); this task stays scoped to the phases 2-6 go/no-go.
+
 * Rulesets Resolved
 ** DONE [#C] Fix =cj-scan= false positives on cj fences nested inside other =#+begin_*= blocks :bug:
 CLOSED: [2026-05-15 Fri]