feat: bounded subagent delegation (v5)

Coordinator parts gain three enforced bounds, validated in
validate_parts and carried through the coordinator_parts JSON
(no schema change): timeout_seconds (1..86400, per-attempt
wall clock from coordinator start; the coordinator poll loop
cancels only that child with the same cancel mechanism as
the global timeout, other parts keep waiting, audit
coordinator_child_bound_exceeded), on_failure fail|tolerate
(tolerated failures do not fail the coordinator, are named
in the report head, and their failed children are not
requeued on coordinator re-run while interrupted children
still are), and result_chars (0..2000, default 500, enforced
in build_report; the 4000-char report writeback cap still
applies). evaluate_outcome is the single outcome rule used
by both build_report and the worker error text, so tolerated
failures never leak into the coordinator failure reason.
Unknown part names fail closed.

Deliberately NOT added, after reading the execution layer:
per-part token/cost budget (cost is recorded only on
completion, so a running child's spend is unobservable and
creator quota is monthly, not per part), per-part round cap
(normal tasks have no per-task round cap in the worker),
and write-scope isolation (sandbox is per-project worktree,
a scope string in a prompt would be an instruction, not a
guarantee). Tests: test_delegation_bounds.py (8 tests).

cloud/coordinator.py

@@ -26,6 +26,37 @@
   （父仍在跑时绝不动子任务）。本模块只提供纯函数
   nonterminal_children 供 worker 判断，DB 写回在 worker 侧。
 
+- 有界委派（v5，Foundry“有界 subagent 委派”的对应物）：
+  每个分工除 name/prompt/model/effort/executor 外，还可带
+  三个显式边界，全部在 validate_parts 校验、经 DB 的
+  coordinator_parts JSON 原样流转、由 worker 的协调员循环
+  真正执行，不是只写进 prompt 的愿望：
+  ① timeout_seconds：该分工单次委派的墙钟上限，从协调员
+  本轮开始计时，超时由协调员循环直接 cancel 该子任务
+  （与全局超时同款 cancel 机制），其他分工继续等，不因
+  一个慢分工拖住整批到全局超时；② on_failure：fail（默认，
+  旧行为，任一非容忍分工未完成则协调员失败）或 tolerate
+  （该分工失败不拖垮协调员，汇总里点名已容忍，协调员
+  重跑时其 failed 子任务不再重排、interrupted 的仍重排，
+  因为后者可能是父任务取消所致、未获公平一轮）；③
+  result_chars：回传给父任务的单项输出上限，默认 500，
+  汇总报告本身仍受 worker 写回的 4000 字上限约束。
+  三个边界的执行点都在协调员层：超时在循环里 cancel，
+  容忍在合流评价里算，截断在汇总报告里切。
+
+- v5 明确不宣称的边界（查代码后的诚实口径，勿以字段
+  冒充执行）：① 每分工 token/费用预算：成本记录只在任务
+  完成时写，运行中的子任务花费在循环里观测不到，创建人
+  配额是按月不是按分工，所以不存在可执行的分工费用门，
+  v5 不加 max_tokens/max_cost 字段；② 每分工轮数上限：
+  普通任务在 worker 侧没有按任务的轮数上限（只有 goal
+  任务的 goal_max_rounds 与 worker 进程级的 max_turns），
+  所以 max_rounds 字段在子任务执行层无法执行，v5 不加；
+  ③ 写范围隔离：沙箱按项目 worktree 隔离、不按分工
+  量子目录隔离，prompt 里写“只写 docs/”是指令不是保证，
+  所以 v5 不加 scope 字段冒充隔离。这三项要做需先改
+  执行层（成本流、轮数帽、沙箱子目录），不在本轨范围。
+
 本模块只放纯逻辑（校验、解析、汇总、建表），不碰 DB 之外的
 任何东西，单测不需要 worker/server。
 """
@@ -36,15 +67,25 @@ MAX_PARTS = 20
 DEFAULT_TIMEOUT_SECONDS = 3600
 DEFAULT_POLL_INTERVAL = 5.0
 REPORT_RESULT_CHARS = 500
+MAX_RESULT_CHARS = 2000
+MAX_TIMEOUT_SECONDS = 86400
+ON_FAILURES = ("fail", "tolerate")
 EFFORTS = {"low", "medium", "high", "xhigh", "max"}
 EXECUTORS = {"local", "docker", "cloud"}
 
 
+def _is_int(value):
+    return isinstance(value, int) and not isinstance(value, bool)
+
+
 def validate_parts(parts):
     """校验 coordinator_parts，返回 (normalized, error)。
 
-    normalized 每项：{name, prompt, model, effort, executor}，
-    未指定的三项为 None（子任务跟随协调员任务或 worker 默认）。
+    normalized 每项：{name, prompt, model, effort, executor,
+    timeout_seconds, on_failure, result_chars}，未指定的模型/
+    强度/执行器为 None（子任务跟随协调员任务或 worker 默认），
+    未指定的 timeout_seconds 为 None（只受全局超时约束），
+    on_failure 默认 fail，result_chars 默认 500。
     """
     if not isinstance(parts, list):
         return None, "coordinator_parts must be a list"
@@ -80,12 +121,34 @@ def validate_parts(parts):
         if executor is not None and executor not in EXECUTORS:
             return None, (
                 "part %s: executor must be local, docker or cloud" % name)
+        timeout = part.get("timeout_seconds")
+        if timeout is not None:
+            if not _is_int(timeout) or not 1 <= timeout <= \
+                    MAX_TIMEOUT_SECONDS:
+                return None, (
+                    "part %s: timeout_seconds must be an integer in"
+                    " 1..%d" % (name, MAX_TIMEOUT_SECONDS))
+        on_failure = part.get("on_failure") or "fail"
+        if on_failure not in ON_FAILURES:
+            return None, (
+                "part %s: on_failure must be fail or tolerate" % name)
+        result_chars = part.get("result_chars")
+        if result_chars is None:
+            result_chars = REPORT_RESULT_CHARS
+        if not _is_int(result_chars) or not 0 <= result_chars <= \
+                MAX_RESULT_CHARS:
+            return None, (
+                "part %s: result_chars must be an integer in"
+                " 0..%d" % (name, MAX_RESULT_CHARS))
         out.append({
             "name": name,
             "prompt": prompt.strip(),
             "model": model.strip() if model else None,
             "effort": effort,
             "executor": executor,
+            "timeout_seconds": timeout,
+            "on_failure": on_failure,
+            "result_chars": result_chars,
         })
     return out, None
 
@@ -163,25 +226,71 @@ def nonterminal_children(children):
     return out
 
 
-def build_report(children):
+def parts_by_name(parts):
+    """分工列表 → {name: part}；parts 为 None 时返回 {}。"""
+    out = {}
+    for part in parts or []:
+        if isinstance(part, dict) and part.get("name"):
+            out[part["name"]] = part
+    return out
+
+
+def evaluate_outcome(children, parts=None):
+    """合流评价（纯函数）：返回 (overall, failed_names,
+    tolerated_names)。
+
+    completed 计完成；未完成的项中，on_failure 为 tolerate
+    的分工计容忍、不拖垮整体，其余计失败。未知分工名按
+    fail 处理（fail-closed，绝不把查不到的分工当容忍）。
+    空 children 时 overall 为 failed（与旧 build_report 一致，
+    失败名为空——调用方按“无子任务”理解，不按名理解）。
+    """
+    by_name = parts_by_name(parts)
+    has_parts = parts is not None
+    done = 0
+    failed = []
+    tolerated = []
+    for ch in children or []:
+        name = ch.get("name")
+        if ch.get("status") == "completed":
+            done += 1
+            continue
+        part = by_name.get(name) if has_parts else None
+        if has_parts and part is not None and \
+                part.get("on_failure") == "tolerate":
+            tolerated.append(name)
+        else:
+            failed.append(name)
+    overall = "completed" if children and not failed else "failed"
+    return overall, failed, tolerated
+
+
+def build_report(children, parts=None):
     """合流汇总：children 为 [{name, id, status, result_text,
     error_text}]，返回 (report_text, overall_status)。
 
-    overall：全部 completed 才 completed，否则 failed（取消与超时
-    路径由调用方直接定 interrupted/failed，不走这里）。单项输出
-    截断到 REPORT_RESULT_CHARS，汇总报告本身仍受 worker 写回的
-    4000 字上限约束（超长时尾部项会被截断，头部计数不受影响）。
+    不传 parts 时为旧行为：全部 completed 才 completed，
+    单项输出截断到 REPORT_RESULT_CHARS。传 parts 时按
+    evaluate_outcome 算总体（容忍分工的失败不拖垮整体，
+    头部点名已容忍项），单项截断按该分工的 result_chars。
+    取消与超时路径由调用方直接定 interrupted/failed，不走
+    这里。汇总报告本身仍受 worker 写回的 4000 字上限约束
+    （超长时尾部项会被截断，头部计数不受影响）。
     """
+    by_name = parts_by_name(parts)
     lines = []
     done = 0
     for ch in children:
         st = ch.get("status") or "?"
         if st == "completed":
             done += 1
+        part = by_name.get(ch.get("name"))
+        chars = part.get("result_chars") if part is not None else \
+            REPORT_RESULT_CHARS
         lines.append("## %s (%s)" % (ch.get("name"), st))
         lines.append("子任务：%s" % ch.get("id"))
-        res = (ch.get("result_text") or "")[:REPORT_RESULT_CHARS]
-        err = (ch.get("error_text") or "")[:REPORT_RESULT_CHARS]
+        res = (ch.get("result_text") or "")[:chars]
+        err = (ch.get("error_text") or "")[:chars]
         if res:
             lines.append(res)
         if err:
@@ -189,7 +298,16 @@ def build_report(children):
         if not res and not err:
             lines.append("（无输出）")
         lines.append("")
-    overall = "completed" if children and done == len(children) else "failed"
-    head = "协调员汇总：%d/%d 个子任务完成，总体 %s" % (
-        done, len(children), overall)
+    if parts is None:
+        overall = "completed" if children and \
+            done == len(children) else "failed"
+        head = "协调员汇总：%d/%d 个子任务完成，总体 %s" % (
+            done, len(children), overall)
+    else:
+        overall, _failed, tolerated = evaluate_outcome(children, parts)
+        head = "协调员汇总：%d/%d 个子任务完成，总体 %s" % (
+            done, len(children), overall)
+        if tolerated:
+            head += "（%d 项失败已容忍：%s）" % (
+                len(tolerated), "、".join(tolerated))
     return head + "\n\n" + "\n".join(lines), overall