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nisse/nisse-dev/src/nisse_dev/llm.py
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dongarandClaude Opus 5 8cfa116aa1
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Preserve delegation work through any upstream outage, not just budget
An exhausted budget was a special case of something more general: the
work is not at fault. A network blip, a timeout, a 5xx from the proxy,
or a rate limit that did not clear all leave a delegation branch that
may be perfectly good, and discarding it would throw away work for a
reason that has nothing to do with the work.

UpstreamUnavailable now names that family, with BudgetExhausted a
member of it — distinguishable where the difference matters, since a
budget will not clear within the hour while a network blip will. A
delegation stopped by any of them is "interrupted": branch kept,
intent left pending, and A3's resume rule picks it up.

The benefit of the doubt stops at the server's own door. A 4xx that is
not a rate limit means the request itself was wrong, and preserving
branches on the strength of one would hide a real bug — so those still
fail and clean up.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
2026-09-22 23:57:05 +00:00

411 lines
15 KiB
Python

"""LLM access (spec A5, A11).
One client interface, present from the first real LLM call. All traffic goes
to the LiteLLM proxy — the VM's single LLM destination; the agent holds one
LiteLLM token and no vendor credentials. Config comes from the environment
(``NISSE_LLM_BASE_URL``, ``NISSE_LLM_TOKEN``), nothing hardcoded.
Model identity is expressed as roles (A11), resolved to concrete model strings
from env config; the resolved mapping is pinned at task start so a mid-task
config change cannot split a task across two planners.
"""
import json
import os
import time
from collections.abc import Mapping
from dataclasses import asdict, dataclass
from typing import Any, ClassVar, Protocol
import httpx
from nisse_dev.canonical import (
AssistantText,
CanonicalEvent,
StoredEvent,
ToolCall,
mint_call_id,
)
from nisse_dev.render import OpenAIChatRenderer
from nisse_dev.render_anthropic import AnthropicMessagesRenderer
class LLMError(RuntimeError):
pass
# A rate limit is a transient condition, not a bad request. Losing a
# ten-turn delegation to one wastes far more tokens than waiting out the
# window, so retry once before surfacing it (A13's caps still bound the
# total).
RATE_LIMIT_STATUS = 429
RATE_LIMIT_RETRY_S = 20.0
# Generous by default. Output is billed by what is produced, not by the
# ceiling, and a ceiling too low does not fail loudly — it truncates a tool
# call mid-argument and hands back something that parses. Measured: Opus
# writing an architecture plan routinely spends 3,000-4,000 output tokens and
# was observed at 4,064 against a 4,096 limit.
DEFAULT_MAX_OUTPUT_TOKENS = 16384
def max_output_tokens(env: Mapping[str, str] = os.environ) -> int:
raw = env.get("NISSE_MAX_OUTPUT_TOKENS")
return int(raw) if raw else DEFAULT_MAX_OUTPUT_TOKENS
class UpstreamUnavailable(LLMError):
"""The proxy or provider could not be reached, or refused for reasons
unrelated to what was asked: a network blip, a timeout, a 5xx, a rate
limit that did not clear, an exhausted budget.
Worth distinguishing because the *work* is not at fault. A delegation
stopped by one of these has a branch that may be perfectly good, so it is
preserved and resumed rather than discarded — unlike a delegate that made
a mess, which is cleaned up.
"""
class BudgetExhausted(UpstreamUnavailable):
"""The proxy refused because a spend limit is gone.
Distinct from the rest of its family because it will not clear on its
own within the hour: an exhausted daily budget takes external models away
until it resets, so retrying wastes time and the operator needs telling.
A5 keeps the budget itself at the proxy; recognising its refusal is ours.
"""
def _looks_like_budget_refusal(text: str) -> bool:
# Pattern-matched rather than contracted: LiteLLM's wording is not a
# documented interface, so this errs toward missing one rather than
# misreporting an unrelated failure as a budget problem.
lowered = text.lower()
return "budget" in lowered and (
"exceed" in lowered or "exhaust" in lowered or "limit" in lowered
)
class TruncatedResponse(LLMError):
"""The model was cut off mid-answer.
Raised rather than returned, because the damage is silent: a truncated
tool call arrives with required arguments simply absent, and a truncated
write_file would write half a file and report success. A cut-off turn is
a failed turn, and every caller already retries or gates on LLMError.
"""
class LLMClient(Protocol):
def complete(
self,
events: list[StoredEvent],
tools: list[dict[str, Any]] | None,
model: str,
system: str | None = None,
) -> list[CanonicalEvent]: ...
@dataclass(frozen=True)
class RoleMap:
executor: str
planner: str
delegate: str
consultant: str
_ENV_VARS: ClassVar[dict[str, str]] = {
"executor": "NISSE_ROLE_EXECUTOR",
"planner": "NISSE_ROLE_PLANNER",
"delegate": "NISSE_ROLE_DELEGATE",
"consultant": "NISSE_ROLE_CONSULTANT",
}
@classmethod
def from_env(cls, env: Mapping[str, str] = os.environ) -> "RoleMap":
missing = [var for var in cls._ENV_VARS.values() if not env.get(var)]
if missing:
raise LLMError(f"role mapping incomplete; set: {', '.join(missing)}")
return cls(**{role: env[var] for role, var in cls._ENV_VARS.items()})
def resolve(self, role: str) -> str:
if role not in self._ENV_VARS:
raise LLMError(f"unknown role: {role!r}")
return str(getattr(self, role))
def pinned(self) -> dict[str, str]:
"""The full resolved mapping, to record at task start (A11)."""
return asdict(self)
class LiteLLMClient:
def __init__(
self,
base_url: str,
token: str,
*,
timeout_s: float = 120.0,
transport: httpx.BaseTransport | None = None,
sleep: Any = time.sleep,
max_tokens: int | None = None,
) -> None:
self._http = httpx.Client(
base_url=base_url.rstrip("/"),
headers={"Authorization": f"Bearer {token}"},
timeout=timeout_s,
transport=transport,
)
self._renderer = OpenAIChatRenderer()
self._sleep = sleep
self._max_tokens = max_tokens or max_output_tokens()
# Set after each call so a caller can meter itself (A13 caps);
# a side channel rather than a return value, so the LLMClient
# protocol stays the same for every implementation.
self.last_usage: dict[str, int] = {}
@classmethod
def from_env(cls, env: Mapping[str, str] = os.environ) -> "LiteLLMClient":
base_url = env.get("NISSE_LLM_BASE_URL")
token = env.get("NISSE_LLM_TOKEN")
if not base_url or not token:
raise LLMError("set NISSE_LLM_BASE_URL and NISSE_LLM_TOKEN")
return cls(base_url, token)
def complete(
self,
events: list[StoredEvent],
tools: list[dict[str, Any]] | None,
model: str,
system: str | None = None,
) -> list[CanonicalEvent]:
body = self._renderer.render(events, tools, model, system=system)
# A ceiling on this route too: without one a runaway turn is bounded
# only by the provider's default, and the same truncation check has
# nothing to check against.
body["max_tokens"] = self._max_tokens
response = _post_with_rate_limit_retry(
self._http, "/chat/completions", body, self._sleep
)
if response.status_code != 200:
_raise_for_upstream(response)
raise LLMError(
f"LLM request returned {response.status_code}: {response.text[:500]}"
)
return self._parse(response.json(), requested_model=model)
def _parse(
self, data: dict[str, Any], requested_model: str
) -> list[CanonicalEvent]:
try:
choice = data["choices"][0]
message = choice["message"]
except (KeyError, IndexError) as exc:
raise LLMError(f"malformed completion response: {exc}") from exc
if choice.get("finish_reason") == "length":
raise TruncatedResponse(
f"{requested_model} hit its output limit mid-answer; "
"raise NISSE_MAX_OUTPUT_TOKENS"
)
produced_by = data.get("model") or requested_model
usage = data.get("usage") or {}
self.last_usage = {
"input": int(usage.get("prompt_tokens") or 0),
"output": int(usage.get("completion_tokens") or 0),
}
out: list[CanonicalEvent] = []
if message.get("content"):
out.append(AssistantText(text=message["content"], model=produced_by))
# Provider tool-call IDs are mapped at the boundary (A10): each call
# gets a locally-minted canonical ID; the provider's is dropped, since
# every future request is rendered wholly from the canonical log.
for call in message.get("tool_calls") or []:
raw = call["function"]["arguments"] or "{}"
# Weak models emit truncated or non-JSON argument strings; that is
# a bad model turn, not a client crash (A15).
try:
arguments = json.loads(raw)
except json.JSONDecodeError as exc:
raise LLMError(
f"tool call {call['function']['name']!r} had non-JSON "
f"arguments: {raw[:200]!r}"
) from exc
if not isinstance(arguments, dict):
raise LLMError(
f"tool call {call['function']['name']!r} arguments were "
f"{type(arguments).__name__}, expected object"
)
out.append(
ToolCall(
call_id=mint_call_id(),
tool=call["function"]["name"],
arguments=arguments,
)
)
return out
def close(self) -> None:
self._http.close()
class AnthropicPassthroughClient:
"""LiteLLM's Anthropic passthrough (A5). Same interface as LiteLLMClient,
so a caller chooses a route rather than a different kind of client.
Delegations take this path because fidelity matters there (A13);
ask_expert and fallbacks use the normalized route, where it does not.
"""
def __init__(
self,
base_url: str,
token: str,
*,
timeout_s: float = 300.0,
max_tokens: int | None = None,
transport: httpx.BaseTransport | None = None,
sleep: Any = time.sleep,
) -> None:
self._http = httpx.Client(
base_url=base_url.rstrip("/"),
headers={
"Authorization": f"Bearer {token}",
"x-api-key": token,
"anthropic-version": "2023-06-01",
},
timeout=timeout_s,
transport=transport,
)
self._renderer = AnthropicMessagesRenderer()
self._max_tokens = max_tokens or max_output_tokens()
self._sleep = sleep
self.last_usage: dict[str, int] = {}
@classmethod
def from_env(
cls, env: Mapping[str, str] = os.environ
) -> "AnthropicPassthroughClient":
base_url = env.get("NISSE_LLM_BASE_URL")
token = env.get("NISSE_LLM_TOKEN")
if not base_url or not token:
raise LLMError("set NISSE_LLM_BASE_URL and NISSE_LLM_TOKEN")
return cls(base_url, token)
def complete(
self,
events: list[StoredEvent],
tools: list[dict[str, Any]] | None,
model: str,
system: str | None = None,
) -> list[CanonicalEvent]:
body = self._renderer.render(
events, tools, model, system=system, max_tokens=self._max_tokens
)
response = _post_with_rate_limit_retry(
self._http, "/v1/messages", body, self._sleep
)
if response.status_code != 200:
_raise_for_upstream(response)
raise LLMError(
f"passthrough returned {response.status_code}: {response.text[:500]}"
)
return self._parse(response.json(), requested_model=model)
def _parse(
self, data: dict[str, Any], requested_model: str
) -> list[CanonicalEvent]:
if data.get("stop_reason") == "max_tokens":
raise TruncatedResponse(
f"{requested_model} hit the output limit of {self._max_tokens} "
f"tokens mid-answer; raise NISSE_MAX_OUTPUT_TOKENS"
)
content = data.get("content")
if not isinstance(content, list):
raise LLMError(f"malformed passthrough response: {str(data)[:300]}")
produced_by = data.get("model") or requested_model
usage = data.get("usage") or {}
self.last_usage = {
"input": int(usage.get("input_tokens") or 0),
"output": int(usage.get("output_tokens") or 0),
}
out: list[CanonicalEvent] = []
for block in content:
kind = block.get("type")
if kind == "text" and block.get("text"):
out.append(AssistantText(text=block["text"], model=produced_by))
elif kind == "tool_use":
# Provider ids are mapped at the boundary and never used as a
# join key (A10); the canonical log owns identity.
out.append(
ToolCall(
call_id=mint_call_id(),
tool=block["name"],
arguments=block.get("input") or {},
)
)
# Vendor-opaque reasoning blocks (thinking, redacted_thinking) are
# deliberately dropped for now: A10 requires storing them tagged
# with the producing model and never replaying them outside the
# session that made them, and the canonical schema has no event
# for that yet. Nothing requests extended thinking, so none arrive.
return out
def close(self) -> None:
self._http.close()
def _post_with_rate_limit_retry(
http: httpx.Client, path: str, body: dict[str, Any], sleep: Any
) -> httpx.Response:
for attempt in (1, 2):
try:
response = http.post(path, json=body)
except httpx.HTTPError as exc:
# Could not reach the proxy at all: nothing about the request was
# wrong, so callers holding work in progress should keep it.
raise UpstreamUnavailable(f"LLM request failed: {exc}") from exc
if response.status_code != RATE_LIMIT_STATUS or attempt == 2:
return response
sleep(RATE_LIMIT_RETRY_S)
raise AssertionError("unreachable")
# Model families we have a native renderer adapter for. A13: delegations take
# the vendor's passthrough route because a normalising middlebox is lossy
# exactly where a long-running delegation lives.
PASSTHROUGH_PREFIXES = ("claude-", "anthropic/")
def has_native_adapter(model: str) -> bool:
return model.startswith(PASSTHROUGH_PREFIXES)
def select_client(
model: str, normalized: LLMClient, passthrough: LLMClient
) -> LLMClient:
"""Choose the route from the model, not from where the caller sits.
A13 spells out the rule: use the vendor-native adapter where one exists,
and otherwise *provisionally* accept LiteLLM's normalization for that
vendor — validating it against the A16 eval set before trusting it with
delegations. Hard-wiring the passthrough would mean pointing a role at a
non-Anthropic model silently sent it Anthropic-shaped request bodies,
which is the opposite of the vendor fluidity A5 requires.
"""
return passthrough if has_native_adapter(model) else normalized
def _raise_for_upstream(response: httpx.Response) -> None:
"""Classify a non-200 as upstream trouble where it plainly is.
A 4xx that is not a rate limit means the request itself was wrong, and
preserving work on the strength of one would hide a real bug — so the
benefit of the doubt stops at the server's own door.
"""
if _looks_like_budget_refusal(response.text):
raise BudgetExhausted(
f"the proxy refused on budget grounds: {response.text[:300]}"
)
if response.status_code >= 500 or response.status_code == RATE_LIMIT_STATUS:
raise UpstreamUnavailable(
f"upstream returned {response.status_code}: {response.text[:300]}"
)