conductor(track): nagent_review_v3 §6 Delegation rewrite cluster

conductor/tracks/nagent_review_20260608/nagent_review_v3_20260619.md

@@ -306,7 +306,49 @@ The `{ssdl}` markers note the abstractions: the provider call is a boundary (B)
 
 ## §6 Delegation rewrite
 
-(filled in by Phase 7 — covers `d56f0f0`, `65787a6`, `315fe9e`)
+**Source:** nagent `d56f0f0`, `65787a6`, `315fe9e` (`bin/nagent:666-673` + `:790-806`, `tests/test_nagent.py:1689-1695`).
+**One-liner:** Delegation is for two reasons — **decomposition** (break a complex task into parts and delegate the parts) or **context isolation** (keep a noisy step's cost as just its result, not its logs/reads). It is NEVER for offloading a single small action whose result is no smaller than doing it yourself — synchronous delegation can recurse without end.
+**Pattern(s) vs v2.3:** UPDATE. v2.3 Pattern 9 ("disposable sub-conversations") noted MMA workers are real subprocesses and delegation is context-management before parallelism. v3 surfaces a recursion bug (file-edit agent → worker → nagent-file-edit → file-edit agent → ... hangs the tree) and fixes it by naming the two reasons for delegation. v2.3's "delegation is for context management" framing was correct but undersold; v3's "context isolation is worth more the longer-lived your conversation is" makes the trade-off explicit. The `315fe9e` commit message ("My earlier commits py_compile'd but did not run the suite — this is the fallout") is a model of honest test-coverage reporting.
+**Manual Slop implications:** MMA's WorkerPool has disciplined delegation (per `docs/guide_multi_agent_conductor.md`); the recursion bug was observed in the non-MMA flow (file-edit agent re-delegating). Manual Slop's tier-3 workers should adopt the "decompose or isolate, never offload" contract explicitly. The 315fe9e test-fix is a useful precedent: an agent's `test_*.py` for any user-facing prompt change must run the suite, not just `py_compile`. Manual Slop's CLAUDE.md / AGENTS.md @import discipline (per `conductor/code_styleguides/data_oriented_design.md`) already encodes "always run the suite" but the temptation to skip on prompt-only changes is real.
+**Decision candidate:** NEW Candidate 22 (HIGH). "Tier 3 worker contract: decompose or isolate, never offload" for Manual Slop MMA — encode the two-reason delegation guidance as a Tier 3 worker system prompt prefix; add a test that asserts the prefix is present in the worker's initial context. See `decisions.md` Candidate 22.
+**Cross-refs:** §1 Campaigns (campaign item workers operate under this discipline); §2 Conversation safety net (sub-conversations inherit the same scoping); §10 + §11 case studies (sub-conversation isolation is what makes the case-study harnesses tractable).
+**Source-read citations:**
+- `bin/nagent:666-673` — `role_instructions` for delegated-invocation: "Do your task directly; spawn a sub-conversation only when it buys something: to decompose a genuinely complex, multi-part task into parts, or to keep a large/noisy step ... out of your context and get back only the distilled result. Don't delegate a single small action whose result is essentially your whole deliverable—that adds a layer and can recurse without end." (65787a6)
+- `bin/nagent:790-806` — top-level context-management guidance: "Each nagent instance has its own private conversation file; parent and child do not share context. A sub-conversation absorbs the noise of its work and returns only what you ask for — so a step you delegate costs your context just its result, not its logs/reads." (65787a6)
+- `bin/nagent:792-798` — the two-reason framing (decomposition OR context isolation), the "worth more the longer-lived your conversation is" insight (65787a6)
+- `bin/nagent:798-800` — anti-recursion rule: "Don't delegate a single small action whose result is no smaller than doing it yourself (one edit, one quick command, one lookup): it buys nothing, only adds a layer, and — delegation being synchronous — can recurse without end (a sub-agent re-delegating the same one thing)." (65787a6)
+- `tests/test_nagent.py:1689-1695` — `test_delegated_initial_text` updated to assert the new wording (315fe9e)
+- `d56f0f0` commit message — the recursion bug: "file-edit agent -> worker -> nagent-file-edit -> file-edit agent -> ..." (observed)
+**Honest gaps in this cluster:**
+- The `315fe9e` commit message's acknowledgment — "My earlier commits py_compile'd but did not run the suite — this is the fallout" — is a model of test-coverage honesty but also a documented gap. The recursion bug itself was caught post-merge by the test; the agent that wrote d56f0f0 + 65787a6 should have run the suite. A future track could enforce "always run the suite" via a pre-commit hook.
+- The recursion-bug fix is guidance-only — no code change prevents the recursion; the model is trusted to follow the new wording. A defensive code change (e.g., a max-delegation-depth check) would harden the invariant. The spec notes the design philosophy: "delegation is the model's call, not the loop's," which is consistent with nagent's data-oriented approach but trades safety for simplicity.
+- The "worth more the longer-lived your conversation is" insight has no measurable test. The conversation-length-vs-delegation-payoff is a heuristic; a future track could measure it.
+
+**Pattern deep-dive.** The delegation rewrite is a guidance + bug-fix pair. The bug is real: a delegated agent whose whole job is one edit will delegate that one edit to another agent, which does the same, and because delegation is synchronous (each parent blocks on its child) this recurses without bound and hangs the tree. The fix is to name the two reasons delegation is worth its cost — decomposition (the task is genuinely complex, with parts) and context isolation (the step is noisy, and the result is small). Both reasons produce a smaller-than-the-work payload to the parent. When neither reason applies, the parent should do the work inline.
+
+The "worth more the longer-lived your conversation is" insight is the load-bearing one. A short, soon-to-finish conversation gains little from context isolation — the cost of paying for the sub-conversation's LLM call may exceed the savings. A long-lived coordinator's context budget is the constraint that context isolation protects. This is the same "per-turn cost" thinking that nagent's hooks (per §3) formalize with `--hook-per-run`'s "point it at a fast status command" guidance — the cost is per-turn, not amortized.
+
+The recursion bug is interesting for what it says about guidance as control flow. nagent's delegation is "the model's call, not the loop's" — the loop does not enforce a max-delegation-depth or refuse to delegate to a child who would delegate. The cost of this design is the recursion bug; the benefit is flexibility. The fix is to make the guidance explicit enough that the model doesn't fall into the trap. This is the data-oriented approach: instead of code-level guards, encode the invariant in the prompt and trust the model to follow it. The test-fix at `315fe9e` is the verification layer.
+
+A code-shape sketch using survey grammar:
+
+```
+delegate { parent_task, sub_task } :: sub-result  {ssdl} [B]
+  // boundary: model decision, not loop enforcement
+  if sub_task is "single small action whose result is the whole deliverable"
+                  -> do inline  // anti-recursion
+  elif sub_task is "multi-part decomposition" or sub_task is "noisy step"
+                  -> spawn sub-conversation
+  else            -> do inline
+
+context-isolation { parent_lifetime, sub_cost } :: bool
+  // worth more the longer-lived the parent is
+  parent_lifetime > threshold and sub_cost > sub_result_size
+```
+
+The `{ssdl}` [B] marker notes the abstraction: delegation is the boundary where the parent's context meets a sub-conversation's work; the cost discipline is per-turn, not amortized. The check is the model's call — no code-level recursion guard exists.
+
+The `315fe9e` commit is the verification-discipline precedent worth carrying forward: any guidance change in a prompt must run the test suite, not just `py_compile`. The diff at `tests/test_nagent.py:1692` is a single character (`"Still decompose and delegate"` → `"spawn a sub-conversation only when it buys something"`), but the assertion was load-bearing — without it, the recursion bug could re-merge silently.
 
 ## §7 Robustness