Files
codex-app-server/cloud/models.py
T
host 1b8b6e525d fix: 9.5-code reachable items (parse unification, goal branch, fail-open logs, M7 test, fingerprint)
Parse: agent_tools/tool_approvals column parsing unified into agent_def shared helpers (parse None = undeclared; server keeps None, worker maps to []/{} at _task_from_row, dispatch behaviour unchanged). Goal: _apply_resume_preamble goal branch proven reachable via _goal_convert_queued on a queued auto-resumed task, kept with a test and corrected docs (not dead code). Fail-open: audit write failure and preamble lookup failure now log warnings (best-effort unchanged); partial policy failure and shadow parse drops documented as known gaps. M7: shadow endpoint explicit_capability_failures_truncated test. Fingerprint: RoutingPolicy.content_fingerprint (canonical JSON sha256, version excluded) surfaced only in dry-run output, never in audit rows. M1 wording: legacy gap stated as fixed stock persisting per-task until completion, not converging.
2026-11-04 18:02:21 +00:00

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"""Model fallback routing and pre-dispatch rule routing (v0).
Zero third-party dependencies; standard library only.
This module decides *whether* a failed model attempt may fall back to
the next model in a priority list, and *which* model to try next. It
never runs a model turn itself and never talks to any provider.
Rule routing (v0) is deliberately narrower than that: it only fills
in the model for tasks that did not specify one, using structural
signals already stored on the task (``plan``, ``goal_mode`` /
``verify_command``). It never changes ``effort``, ``approval``,
``plan``, ``executor`` or any quota, never switches provider/gateway,
and never invents a quality ranking between models. A policy that
cannot be parsed, or a tier with no model, falls back to the existing
worker-default chain instead of failing the task.
"""
import json
import logging
import os
_logger = logging.getLogger("cloud.models")
FALLBACKABLE = {404, 429, 500, 502, 503, 504, "timeout"}
def _is_fallbackable_code(value):
"""Return True for a single status code / error token."""
if isinstance(value, bool):
return False
if isinstance(value, int):
if value in FALLBACKABLE:
return True
# Any other 5xx is a server-side failure of the same kind.
return 500 <= value <= 599
if isinstance(value, str):
text = value.strip().lower()
if text in FALLBACKABLE:
return True
if text.isdigit():
return _is_fallbackable_code(int(text))
return False
return False
def is_fallbackable(error) -> bool:
"""Return True if ``error`` may trigger a model fallback.
``error`` may be:
* an int HTTP status code (404, 429, 5xx -> True; 401, 400 -> False);
* the string ``"timeout"``;
* an object / exception carrying a ``status`` or ``code`` attribute
holding one of the above.
Authentication failures (401) and bad-request errors (400) are
deliberately *not* fallbackable: retrying them on another model
cannot fix bad credentials or a bad request.
"""
if error is None:
return False
if isinstance(error, (int, str)) and not isinstance(error, bool):
return _is_fallbackable_code(error)
for attr in ("status", "code"):
value = getattr(error, attr, None)
if value is not None:
return _is_fallbackable_code(value)
return False
class ModelRouter:
"""Walk a priority list of models, one fallback at a time."""
def __init__(self, priority_list):
if not priority_list:
raise ValueError("priority_list must not be empty")
self.priority_list = list(priority_list)
def first(self):
"""Return the first (highest-priority) model."""
return self.priority_list[0]
def next_after(self, current_model, error):
"""Return the model after ``current_model``, or None.
Returns None when ``error`` is not fallbackable, when
``current_model`` is not in the priority list, or when there
is no model left after ``current_model``.
"""
if not is_fallbackable(error):
return None
try:
index = self.priority_list.index(current_model)
except ValueError:
return None
if index + 1 < len(self.priority_list):
return self.priority_list[index + 1]
return None
def route(self, attempts):
"""Return the next model to try given ``attempts``, or None.
``attempts`` is a list of ``(model, error)`` pairs in the order
they were tried. With no attempts yet, the next model to try
is the first in the priority list. A non-fallbackable error
anywhere in the chain stops routing (returns None), as does
exhausting the priority list.
"""
if not attempts:
return self.first()
last_model = None
for model, error in attempts:
if not is_fallbackable(error):
return None
last_model = model
return self.next_after(last_model, attempts[-1][1])
ROUTING_MODES = ("off", "shadow", "active")
ROUTING_TIERS = ("plan", "goal", "default")
# 能力路由(v8):能力目录与档需求的字段名。布尔能力只认
# True 为“具备”,False 为“已知不具备”,缺失为“未知”——
# 缺失绝不按 False 算(那会把“没声明”说成“没能力”),
# 也绝不按 True 算(那会把“没声明”说成“有能力”)。
CAPABILITY_BOOL_KEYS = ("tool_calling", "reasoning", "vision")
CAPABILITY_INT_KEYS = ("context_tokens",)
REQUIREMENT_BOOL_KEYS = CAPABILITY_BOOL_KEYS
REQUIREMENT_INT_KEYS = ("min_context_tokens",)
def _is_bool(value):
return isinstance(value, bool)
def _is_int(value):
return isinstance(value, int) and not isinstance(value, bool)
def parse_model_capabilities(raw):
"""清洗能力目录:{model: {context_tokens, tool_calling,
reasoning, vision}},只保留字段全合法的条目。
目录是运营方手工维护的声明,不是中转 /models 的实测
(中转只回 id,不回能力与价格,见路由 v0 的价格口径):
运营方写错一个条目时,整条丢掉比只丢错字段更安全——
只丢错字段会让“要求工具调用”悄悄变成“不查工具调用”。
非 dict、模型名为空、context_tokens 非正整数、布尔
能力非布尔,一律整条丢掉,调用方据此把该模型的能力
判为未知。
"""
out = {}
if not isinstance(raw, dict):
return out
for model, entry in raw.items():
model = _clean_model_name(model)
if not model or not isinstance(entry, dict):
continue
cleaned = {}
valid = True
for key in CAPABILITY_INT_KEYS:
if key in entry:
if not _is_int(entry[key]) or entry[key] <= 0:
valid = False
break
cleaned[key] = entry[key]
if not valid:
continue
for key in CAPABILITY_BOOL_KEYS:
if key in entry:
if not _is_bool(entry[key]):
valid = False
break
cleaned[key] = entry[key]
if not valid:
continue
out[model] = cleaned
return out
def parse_tier_requires(raw):
"""校验一档的需求:返回清洗后的 dict,或 None 表示非法。
合法需求:布尔能力键只接受布尔值(False 等于“无此
要求”,不是“要求不具备”);min_context_tokens 只接受
正整数;未知键一律非法——运营方拼错需求名时,若静默
忽略,他会以为该要求已生效,实际没生效。非法需求的
处理在 parse_routing_policy:整档丢掉(与无效档模式
同款 fail-closed),不连累其他档。
"""
if raw is None:
return {}
if not isinstance(raw, dict):
return None
out = {}
for key, value in raw.items():
if key in REQUIREMENT_BOOL_KEYS:
if not _is_bool(value):
return None
if value:
out[key] = True
elif key in REQUIREMENT_INT_KEYS:
if not _is_int(value) or value <= 0:
return None
out[key] = value
else:
return None
return out
def check_model_capabilities(capabilities, model, requires):
"""查一个模型是否满足需求:返回 (ok, missing, unknown)。
requires 为空时恒为 ok。模型不在目录里时全部需求都
无法验证:ok=False,missing 列全部需求名,unknown=True。
目录里有模型但某项能力缺失时,该项计 unknown(不是
已知不具备),missing 里同样列它——active 模式下
fail 与 unknown 都拦任务,区别只在报错文案里写清是
“已知缺乏”还是“无法验证”。
"""
requires = requires or {}
if not requires:
return True, [], False
model = _clean_model_name(model)
entry = (capabilities or {}).get(model) if model else None
if entry is None:
return False, sorted(requires.keys()), True
missing = []
unknown = False
for key, value in requires.items():
if key in REQUIREMENT_BOOL_KEYS:
flag = entry.get(key)
if flag is True:
continue
missing.append(key)
if flag is None:
unknown = True
elif key in REQUIREMENT_INT_KEYS:
context = entry.get("context_tokens")
if context is None:
missing.append(key)
unknown = True
elif context < value:
missing.append(key)
return (not missing), sorted(missing), unknown
def split_model_capability_missing(capabilities, model, requires):
"""把 check_model_capabilities 的缺项拆成已知 / 未知两档。
Audit fix 4(第三遍审计分档建议):显式模型的网关检查不能
只用 (missing, unknown) 的总口径——unknown 为真时可能是
“目录里根本没有该模型”,也可能是“条目里某项能力没填”,
两者决策不同。返回 (known_missing, unknown_missing):
- 目录里没有该模型:全部需求都算 unknown,known 为空;
- 布尔能力明确为 False、或 context_tokens 明确低于需求:
known(目录明确写了不满足);
- 布尔能力未填(None)、或 context_tokens 未填:unknown。
与 check_model_capabilities 的口径一致:requires 里非布尔/
非整数键被忽略,不计入任何一档。
"""
requires = requires or {}
model = _clean_model_name(model)
entry = (capabilities or {}).get(model) if model else None
if entry is None:
return [], sorted(
k for k in requires
if k in REQUIREMENT_BOOL_KEYS or k in REQUIREMENT_INT_KEYS)
known = []
unknown = []
for key, value in requires.items():
if key in REQUIREMENT_BOOL_KEYS:
flag = entry.get(key)
if flag is True:
continue
if flag is None:
unknown.append(key)
else:
known.append(key)
elif key in REQUIREMENT_INT_KEYS:
context = entry.get("context_tokens")
if context is None:
unknown.append(key)
elif context < value:
known.append(key)
return sorted(known), sorted(unknown)
def prompt_len_bucket(prompt) -> str:
"""Bucket a prompt by length for logging only, never for routing.
Length is recorded so shadow reports can test whether it correlates
with outcomes; v0 deliberately does not route on it (a long prompt
may just be a pasted log, not a hard task).
"""
length = len(prompt) if isinstance(prompt, str) else 0
if length < 500:
return "<500"
if length <= 3000:
return "500-3000"
return ">3000"
def classify_task(task) -> str:
"""Classify a task into one routing tier, first match wins.
Only structural signals are used, in this order: ``plan`` (read-only,
never mutates files) before ``goal`` (multi-round goal loop, possibly
unbounded rounds), everything else is ``default``. Keyword, prompt
length, priority, ``depends_on`` count and executor are intentionally
excluded: they are weak or unrelated proxies for difficulty.
"""
if not isinstance(task, dict):
return "default"
if task.get("plan"):
return "plan"
if task.get("goal_mode") or task.get("verify_command"):
return "goal"
return "default"
def _clean_model_name(value):
# Audit fix 3(M7,文档级):只 strip、不校验字符集。
# 含空白的模型名仍会原样进审计 detail,而影子审计
# 格式是空白分隔,整行解析失败即无声丢样本(不报错、
# 不计数)。这里不加字符集校验——那会改变模型名接受
# 语义、可能拦住合法模型名;风险以文档记录,修复
# 需另起一轨(审计格式改分隔或模型名白名单)。
if isinstance(value, str) and value.strip():
return value.strip()
return None
def _clean_tiers(raw):
"""Return {tier: model} keeping only valid non-empty entries."""
tiers = {}
if not isinstance(raw, dict):
return tiers
for tier in ROUTING_TIERS:
model = _clean_model_name(raw.get(tier))
if isinstance(model, str):
# A tier entry may itself be a dict {"model": ...}; accept
# that shape too so policy authors are not punished for it.
tiers[tier] = model
elif isinstance(raw.get(tier), dict):
model = _clean_model_name(raw[tier].get("model"))
if model:
tiers[tier] = model
return tiers
class RoutingPolicy:
"""A parsed, versioned routing policy (or an empty one).
``mode`` is one of ``off`` / ``shadow`` / ``active`` and is the
default for every tier. ``tiers`` maps a tier name to a model
name; a tier absent from the map falls back to the worker
default. ``tier_modes`` (v0c, per-tier activation) maps a tier
name to an explicit mode that overrides the global ``mode`` in
both directions: a tier can be ``active`` while the global mode
is ``shadow``/``off`` (activate plan first), and a tier can be
``off`` while the global mode is ``active`` (roll back one tier
without touching the others). A tier entry whose mode is not a
valid mode is dropped entirely by the parser (fail-closed: a
typo must never accidentally activate a tier).
``fallback_models`` is parsed and validated but deliberately
NOT applied by v0: the worker's explicit ``--fallback-models``
remains the only source that can enable a real fallback retry,
so a policy file alone can never start burning a second
attempt's quota.
``model_capabilities`` (v8) is the operator-declared
capability directory, and ``tier_requirements`` maps a tier
to its requires dict; both are filtered to tiers/models
that actually exist, exactly like ``tier_modes``.
"""
def __init__(self, version=None, mode="shadow", tiers=None,
fallback_models=None, tier_modes=None,
model_capabilities=None, tier_requirements=None):
self.version = version if isinstance(version, str) \
and version.strip() else None
self.mode = mode if mode in ROUTING_MODES else "off"
self.tiers = dict(tiers or {})
self.tier_modes = {}
for tier, tier_mode in (tier_modes or {}).items():
if tier in self.tiers and tier_mode in ROUTING_MODES:
self.tier_modes[tier] = tier_mode
# Audit fix: fallback_models used to live after the
# return in tier_mode (unreachable dead code), so a
# RoutingPolicy never actually had the attribute and
# any future reader would get AttributeError. It is
# stored here, cleaned and deduplicated, and still
# deliberately NOT applied by the router (see class
# docstring): only worker CLI --fallback-models enables
# a real fallback retry.
self.fallback_models = []
for item in fallback_models or []:
model = _clean_model_name(item)
if model and model not in self.fallback_models:
self.fallback_models.append(model)
self.model_capabilities = parse_model_capabilities(
model_capabilities)
self.tier_requirements = {}
for tier, requires in (tier_requirements or {}).items():
if tier in self.tiers and requires:
cleaned = parse_tier_requires(requires)
if cleaned is not None:
self.tier_requirements[tier] = cleaned
def tier_mode(self, tier):
"""Effective mode for one tier: explicit tier mode, else global."""
return self.tier_modes.get(tier, self.mode)
def content_fingerprint(self):
"""Content fingerprint of the parsed policy (9.5-code).
sha256 of the canonical JSON (sorted keys, tight
separators) over the fields that decide routing and
capability checks: mode, tiers, tier_modes,
tier_requirements, model_capabilities, fallback_models.
The operator-declared ``version`` string is deliberately
NOT part of the fingerprint: it is hand-filled and may
stay unchanged while requires change, so it cannot be
trusted to detect a change. The fingerprint is only for
dry-run output and debugging; it is never written into
worker_routing audit rows, so the shadow parser (which
splits audit detail on whitespace) is untouched.
Two policies that parse to the same effective fields
share a fingerprint even if their raw documents differ
in key order or in dropped/invalid tiers.
"""
import hashlib
payload = {
"mode": self.mode,
"tiers": self.tiers,
"tier_modes": self.tier_modes,
"tier_requirements": self.tier_requirements,
"model_capabilities": self.model_capabilities,
"fallback_models": self.fallback_models,
}
canonical = json.dumps(payload, sort_keys=True,
separators=(",", ":"))
return hashlib.sha256(canonical.encode("utf-8")).hexdigest()
def parse_routing_policy(data):
"""Parse one policy document, or return None when it is unusable.
Unusable means: not a dict, no usable ``tiers`` map, or a ``mode``
outside ``off``/``shadow``/``active``. Returning None (instead of
raising) is the fail-closed path: the caller falls back to the
worker-default chain and the task is never rejected for a bad
policy file.
"""
if not isinstance(data, dict):
return None
mode = data.get("mode", "shadow")
if mode not in ROUTING_MODES:
return None
tiers = _clean_tiers(data.get("tiers"))
if not tiers:
return None
# Per-tier modes (v0c): a tier entry may be a string (model,
# mode inherits global) or a dict {"model": ..., "mode": ...}.
# An invalid tier mode drops the whole tier entry (fail-closed),
# it never falls back to the global mode where a typo could
# accidentally activate, and never kills the other tiers.
raw_tiers = data.get("tiers") if isinstance(data.get("tiers"),
dict) else {}
tier_modes = {}
for tier, entry in raw_tiers.items():
if not isinstance(entry, dict) or "mode" not in entry:
continue
tier_mode = entry.get("mode")
if tier_mode in ROUTING_MODES:
tier_modes[tier] = tier_mode
else:
tiers.pop(tier, None)
if not tiers:
return None
# Per-tier requirements (v8): a tier entry dict may carry
# "requires". An invalid requires (unknown key, bad value)
# drops the whole tier entry, same fail-closed rule as an
# invalid mode: a typo'd requirement must never be silently
# ignored while the operator believes it is enforced.
tier_requirements = {}
for tier, entry in raw_tiers.items():
if not isinstance(entry, dict) or "requires" not in entry:
continue
cleaned = parse_tier_requires(entry.get("requires"))
if cleaned is None:
tiers.pop(tier, None)
elif cleaned:
tier_requirements[tier] = cleaned
if not tiers:
return None
fallback_models = data.get("fallback_models")
if fallback_models is not None and not isinstance(fallback_models,
list):
return None
return RoutingPolicy(version=data.get("version"), mode=mode,
tiers=tiers, fallback_models=fallback_models,
tier_modes=tier_modes,
model_capabilities=data.get(
"model_capabilities"),
tier_requirements=tier_requirements)
def load_routing_policy(env=None):
"""Load a policy from env, following the cost-table convention.
``CLOUD_ROUTING_POLICY_FILE`` is read first, then
``CLOUD_ROUTING_POLICY_JSON`` overrides its fields per tier;
``CLOUD_ROUTING_MODE`` overrides the mode when valid. Any source
that fails to parse is ignored, never fatal, but the failure is
logged as a warning (Audit fix 3, I3): an unconfigured policy
is silent, a configured-but-broken one is not. Returns None
when no usable policy was found, so the caller keeps the old
behaviour.
"""
env = env if env is not None else os.environ
merged = None
# Audit fix 3(I3):区分“未配置策略”(无 env,正常,
# 不记警告)与“配置了但解析失败”(异常,必须可见)。
# 旧版任一来源失败都静默吞掉,运营方无法区分
# “策略生效”与“策略已死”。行为不变:失败仍返回
# None、派发回落旧链,只是失败现在记警告日志;
# worker 侧另有 routing_policy_load_failed 标志与
# 审计(见 worker.py),让失败在运行期也可查。
configured = bool(env.get("CLOUD_ROUTING_POLICY_FILE")
or env.get("CLOUD_ROUTING_POLICY_JSON"))
failures = []
path = env.get("CLOUD_ROUTING_POLICY_FILE") or ""
if path:
try:
with open(path, encoding="utf-8") as f:
merged = json.load(f)
except (OSError, ValueError) as exc:
failures.append("policy file %r: %s" % (path, exc))
merged = None
raw = env.get("CLOUD_ROUTING_POLICY_JSON") or ""
if raw:
try:
override = json.loads(raw)
except ValueError as exc:
failures.append("CLOUD_ROUTING_POLICY_JSON: %s" % exc)
override = None
if isinstance(override, dict):
if not isinstance(merged, dict):
merged = override
else:
merged = dict(merged)
merged.update(override)
if isinstance(merged.get("tiers"), dict) and \
isinstance(override.get("tiers"), dict):
tiers = dict(merged["tiers"])
tiers.update(override["tiers"])
merged["tiers"] = tiers
policy = parse_routing_policy(merged)
if policy is None:
if configured:
failures.append("merged policy document is unusable")
if failures:
_logger.warning(
"routing policy load failed (%s); falling back to"
" worker default", "; ".join(failures))
return None
if failures:
# 9.5-code fail-open 清单:部分失败是 fail-open——
# 可用来源继续生效、失败来源被丢弃,派发不炸。
# 可见性只有这条警告日志:load_routing_policy 仍
# 返回一个 policy,worker 的
# routing_policy_load_failed 标志只在全失败时
# 置位,所以部分失败不会产生任务级审计;运营方
# 只能从 worker 日志看到它,不能从审计里查到。
# 这是已知缺口(非静默,但不如全失败可见),
# 改动返回类型会牵动全部调用方,本轨不改。
_logger.warning(
"routing policy partially failed (%s); continuing with"
" the usable source", "; ".join(failures))
mode_override = env.get("CLOUD_ROUTING_MODE") or ""
if mode_override in ROUTING_MODES:
policy.mode = mode_override
return policy
class RoutingDecision:
"""One pre-dispatch model decision, kept auditable by construction."""
def __init__(self, task_id, tier, chosen_model, suggested_model,
source, policy_version, applied, reason, signals,
capability_fallback=False):
self.task_id = task_id
self.tier = tier
self.chosen_model = chosen_model
self.suggested_model = suggested_model
self.source = source
self.policy_version = policy_version
self.applied = applied
self.reason = reason
self.signals = dict(signals or {})
# Audit fix: True only when an active tier model failed
# its capability check and the worker default was used
# instead. The source stays "worker_default" (existing
# callers rely on it), so the worker must check this
# flag to audit the fallback -- otherwise the fallback
# is invisible in the audit trail.
self.capability_fallback = bool(capability_fallback)
def to_event(self) -> dict:
return {
"type": "model_routing",
"task_id": self.task_id,
"tier": self.tier,
"chosen_model": self.chosen_model,
"suggested_model": self.suggested_model,
"source": self.source,
"policy_version": self.policy_version,
"applied": self.applied,
"reason": self.reason,
"capability_fallback": self.capability_fallback,
}
def decide_routing(task, worker_model, policy=None,
worker_model_explicit=False):
"""Decide the model for one task, in the documented priority order.
1. task-level ``model`` (explicit) -- never overridden;
2. worker CLI ``--model`` (explicit) -- a pinned deployment is never
silently changed by a policy file;
3. policy tier model in the tier's effective mode (v0c: explicit
tier mode, else the global mode) -- only when the task named
no model; ``active`` applies the tier model, ``shadow``
suggests it, ``off`` falls back to the worker default;
4. worker default chain (config file / ``DEFAULT_MODEL``).
Capability filter (v8): when the tier carries ``requires``,
the policy tier model is checked against the policy's
``model_capabilities`` directory. Explicit task models and
worker CLI models are never checked -- an explicit choice
is never overridden by a policy. In ``shadow`` mode a
mismatch only annotates the reason (shadow never changes
behaviour, never blocks). In ``active`` mode a mismatch
first tries the worker default: if the worker default
satisfies the same requirements it is used instead (source
worker_default, reason names the tier model's shortfall);
if the worker default also fails or is unknown, the
decision is ``source="capability_blocked"`` with
``chosen_model=None`` -- the worker turns that into a
failed task with a clear error (same fail-fast shape as
the v3 required-tools gate), never silently dispatching
an incapable or unverifiable model. A tier with no
requirements, and a policy with no directory, behave
exactly as before. The directory is operator-declared,
never fetched from a provider, so a stale directory is
the operator's responsibility to fix; the dry-run tool
reports capability mismatches before activation.
Shadow mode returns the worker default as ``chosen_model`` and the
policy tier model as ``suggested_model`` with ``applied=False``:
it observes without changing behaviour. This function is pure: it
never reads env, files, or a provider, so it is unit-testable with
plain dicts.
"""
task = task if isinstance(task, dict) else {}
tier = classify_task(task)
signals = {
"plan": bool(task.get("plan")),
"goal_mode": bool(task.get("goal_mode")),
"prompt_len_bucket": prompt_len_bucket(task.get("prompt")),
"effort": task.get("effort"),
}
task_model = _clean_model_name(task.get("model"))
if task_model:
return RoutingDecision(
task_id=task.get("id"), tier=tier, chosen_model=task_model,
suggested_model=None, source="explicit", policy_version=None,
applied=True, reason="task model explicit", signals=signals)
worker_model = _clean_model_name(worker_model)
if worker_model_explicit and worker_model:
return RoutingDecision(
task_id=task.get("id"), tier=tier, chosen_model=worker_model,
suggested_model=None, source="worker_explicit",
policy_version=None, applied=True,
reason="worker CLI model explicit", signals=signals)
if policy is None:
return RoutingDecision(
task_id=task.get("id"), tier=tier, chosen_model=worker_model,
suggested_model=None, source="worker_default",
policy_version=None,
applied=True, reason="routing off or no policy",
signals=signals)
tier_model = policy.tiers.get(tier)
if not tier_model:
return RoutingDecision(
task_id=task.get("id"), tier=tier, chosen_model=worker_model,
suggested_model=None, source="worker_default",
policy_version=policy.version, applied=True,
reason="%s tier has no policy model" % tier, signals=signals)
# Per-tier effective mode (v0c): explicit tier mode overrides
# the global mode in both directions. A tier in "off" is not
# routed at all (no policy/shadow audit downstream, so it never
# inflates a shadow sample count).
effective_mode = policy.tier_mode(tier)
if effective_mode == "off":
return RoutingDecision(
task_id=task.get("id"), tier=tier, chosen_model=worker_model,
suggested_model=None, source="worker_default",
policy_version=policy.version, applied=True,
reason="%s tier mode is off" % tier, signals=signals)
requires = policy.tier_requirements.get(tier) or {}
cap_ok, cap_missing, cap_unknown = check_model_capabilities(
policy.model_capabilities, tier_model, requires)
cap_note = ""
if requires and not cap_ok:
cap_note = " (capability %s: %s)" % (
"unknown" if cap_unknown else "lacks",
", ".join(cap_missing))
if effective_mode == "shadow":
return RoutingDecision(
task_id=task.get("id"), tier=tier, chosen_model=worker_model,
suggested_model=tier_model, source="shadow",
policy_version=policy.version, applied=False,
reason="%s tier suggests %s (shadow, not applied)%s"
% (tier, tier_model, cap_note), signals=signals)
# effective_mode == "active"
if cap_ok:
return RoutingDecision(
task_id=task.get("id"), tier=tier, chosen_model=tier_model,
suggested_model=None, source="policy",
policy_version=policy.version, applied=True,
reason="%s tier -> %s" % (tier, tier_model),
signals=signals)
# Tier model cannot be verified as capable. Try the worker
# default against the same requirements before blocking:
# a capable worker default keeps the task moving without
# violating the requirement.
worker_ok, _w_missing, _w_unknown = check_model_capabilities(
policy.model_capabilities, worker_model, requires)
if worker_ok:
return RoutingDecision(
task_id=task.get("id"), tier=tier, chosen_model=worker_model,
suggested_model=None, source="worker_default",
policy_version=policy.version, applied=True,
reason="%s tier model %s%s, worker default satisfies"
" requirements, falling back" % (tier, tier_model, cap_note),
signals=signals, capability_fallback=True)
return RoutingDecision(
task_id=task.get("id"), tier=tier, chosen_model=None,
suggested_model=tier_model, source="capability_blocked",
policy_version=policy.version, applied=False,
reason="%s tier model %s%s and worker default also cannot"
" satisfy requirements; refusing to dispatch an incapable"
" or unverifiable model" % (tier, tier_model, cap_note),
signals=signals)
def record_routing(task_record, decision) -> dict:
"""Append a ``model_routing`` event to a task record, like fallback.
Mirrors ``record_fallback``: the event is appended to
``task_record["events"]`` (created if absent) so a routed model is
never silent. Returns the event.
"""
event = decision.to_event() if isinstance(decision, RoutingDecision) \
else dict(decision)
events = task_record.get("events")
if not isinstance(events, list):
events = []
task_record["events"] = events
events.append(event)
return event
def record_fallback(task_record, from_model, to_model, reason) -> dict:
"""Record a model fallback on ``task_record`` and return the event.
Fallback must be recorded as an event, never silently downgraded:
the returned event is appended to ``task_record["events"]``
(created if absent) so the downgrade is always visible in the
task's history.
"""
event = {
"type": "model_fallback",
"task_id": task_record.get("id"),
"from_model": from_model,
"to_model": to_model,
"reason": reason,
}
events = task_record.get("events")
if not isinstance(events, list):
events = []
task_record["events"] = events
events.append(event)
return event