Files
interactive-story/backend/app/providers/openai_compatible.py
T
JesseMarkowitzandClaude Opus 5 d63804f22e v1.1: harden context window and narrator protocol boundary
WP-A1 and WP-A2, implemented in sequence, plus the corrective work the owner
asked for at review. Reported in
planning/reports/v1.1/V1.1-WP-A1-A2-REPORT.md (corrective addendum §R).
Planning package v4.2.

WP-A1: context-window safety reserve
- The prompt leaves max(256, ceil(5% of the effective window)) tokens free
  beside the reply. That is 256 at 4,096 and 820 at 16,384. The value is fixed,
  not a setting, and not calibrated per model.
- M6's 64-token margin is gone. Separators and the chat hint are priced
  exactly; tokenizer drift is the reserve's job.
- Protected context that cannot fit raises ContextOverflow before the model
  is called.
- Streams set stream_options.include_usage. Measured on Ollama 0.33, a stream
  sent no usage without it.
- Each sent turn records fits, exceeded, truncation_suspected or unknown.
  The status is returned on the done event, logged when bad, and shown in the
  context inspector. The turn is always kept.
- Accounting is per-attempt data (attempts.ATTEMPT_KEYS).
- Corrective: a cold model is loaded before its turn is built. When the
  window is unverified but the server answered, contextwindow.ensure_window
  makes one bounded POST /api/generate naming only the model. It sends no
  prompt, generates nothing and writes nothing. It then probes again, and the
  turn is built to that answer. If the load fails, or the window is still
  unknown, the turn falls back to the old behaviour.
- Real host, 4,096 window:
  - v1 cold turn: sent 13,875, the server read 2,050.
  - Same turn after the correction: the window was verified, 3,082 sent,
    3,097 read, fits, 499 tokens left beside the reply.
  - Verified turns elsewhere left 275-2,297 tokens against v1's 23-42.

WP-A2: protocol echo and genre-neutral state prompting
- The vocabulary is shown as the JSON object the model sends, not as
  name(field, ...). This costs 121 tokens.
- The example uses character-1, item-1 and location-1.
- The extractor removes shapes anchored to application-owned text:
  - a vocabulary call line;
  - an echoed length hint;
  - the renderer's scene line left last;
  - an empty fence opener.
- Corrective R5: the echoed continue hint is recognised by its own sentence
  ("Output only story text"). A Hard-limit-opened bracket is removed only
  directly above an echo already cut from the same reply.
- Replay of all 518 real v1 replies: 9 changed, 0 flagged, and no story prose
  removed. That is unchanged by R5.
- Replay of 64 v1.1 replies: 3 changed, 0 flagged. The depth-16 instruction
  tail is removed.
- Identity diagnostic after the correction:
  - 0 identity signals;
  - 0 prompt example identifiers proposed;
  - 0/10 stored turns with protocol or instruction shapes.
- 50-turn run: 51 accepted, 0 of 54 stored turns carry protocol.
- SPECS, render.py and validate.py are identical to v1.0.0.

Compatibility: a real v1.0.0 database reads identically on v1.0.0 and v1.1,
field for field, with schema and user_version 94 unchanged. Undo, redo, Save
Point restore, export and import all work on it. There is no schema,
migration or bundle-format change.

Verification: the backend suite passes 1,534 with 17 skipped and 0 failed.
The frontend passes 165/165, and lint and the build are clean. The offline
container and the browser regression were re-run on this tree (see §R.3).

One test was re-calibrated, not weakened: test_history_block_trim's prefix
test had assumed which turn holds the floor at a 2,048 budget.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01VvegagkhuCZoFPdv4M1egY
2026-09-14 16:35:05 -04:00

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import json
from typing import AsyncIterator
import httpx
from .. import debuglog, endpoints, tlstrust
from .base import PromptParts, Provider, ProviderError
# Appended after the story text in chat mode, so a chat-tuned model continues
# the prose rather than replying conversationally.
CHAT_CONTINUE_HINT = "\n\n[Continue the story directly. Output only story text.]"
# A machine that is not listening refuses in milliseconds, so a slow connect
# means the wrong address rather than a busy model.
CONNECT_TIMEOUT = 10.0
# How long to wait for generation when Settings names no value. Upstream
# hardcoded 120s, and M1 measured a *cold* load of a 3B model on a GPU-less
# four-core host exceeding it three times while the same turn took 6-9 seconds
# once the model was resident. 300s covers a cold start on modest hardware and
# is still a number: a wedged endpoint fails rather than hanging forever.
DEFAULT_READ_TIMEOUT = 300.0
# Embeddings are short and never cold-load a large model.
EMBED_READ_TIMEOUT = 60.0
#: v1.1 WP-A1: ask a stream to report its token usage. Without it Ollama sends
#: none, and a prompt the server cut cannot be told from one it read whole.
STREAM_OPTIONS = {"include_usage": True}
# Completion endpoints have no roles, so a chat has to be flattened into one
# labeled transcript that ends on "Assistant:" for the model to continue.
_ROLE_LABELS = {"system": "System", "user": "User", "assistant": "Assistant"}
def flatten_messages(messages: list[dict]) -> str:
turns = "\n\n".join(
f"{_ROLE_LABELS.get(m['role'], m['role'])}: {m['content']}" for m in messages
)
return f"{turns}\n\nAssistant:"
class OpenAICompatibleProvider(Provider):
"""Adapter for Ollama's OpenAI-compatible `/v1` API.
The protocol is OpenAI's, which is what the module is named for; the
product speaks it to Ollama and to nothing else. `endpoints.py` decides
which addresses may be reached, and every request re-checks — the shape of
the wire format is not the same thing as permission to use it.
"""
def __init__(
self,
endpoint_url: str,
model: str,
api_mode: str = "chat",
read_timeout: float | None = None,
):
self.base_url = endpoint_url.rstrip("/")
self.model = model
self.api_mode = api_mode # Either "chat" or "completion".
# How long to wait for the model, in seconds. Cold-loading a model on a
# CPU-only machine can take minutes, and a fixed short timeout reports
# that as a failure. See `DEFAULT_READ_TIMEOUT`.
self.read_timeout = read_timeout or DEFAULT_READ_TIMEOUT
# The token accounting from the last call, when the endpoint reported
# any. Every request method writes it, so a caller reads it after the
# call it made. One provider is built per request.
self.last_usage: dict | None = None
def _headers(self) -> dict:
# No Authorization header: Ollama does not use one, and this build has
# no cloud provider to carry a key for.
return {"Content-Type": "application/json"}
def _timeout(self, seconds: float | None = None) -> httpx.Timeout:
"""Short to connect, patient to read.
A machine that is not listening says so in milliseconds, so a slow
connect is a wrong address rather than a busy model and should fail
fast. Generation is the opposite: the first token can be minutes away
while a model loads.
"""
return httpx.Timeout(seconds or self.read_timeout, connect=CONNECT_TIMEOUT)
def _record_usage(self, payload: dict) -> None:
"""Records the endpoint's own token accounting, if it reported any.
In a stream the usage arrives on a final chunk that carries no choices,
which is why this is read separately from the text extraction.
v1.1 WP-A1: Ollama sends that chunk only when asked. Measured on Ollama
0.33: a stream with no `stream_options` carried no usage at all, and not
one of the 514 AI turns in the v1 evidence had a count stored. Every
streaming body therefore sets `stream_options.include_usage`
(`STREAM_OPTIONS`), and the turn compares the count with what it sent.
"""
usage = payload.get("usage")
if isinstance(usage, dict) and usage:
self.last_usage = usage
def _request(self, parts: PromptParts, temperature: float, max_tokens: int) -> tuple[str, dict]:
if self.api_mode == "completion":
url = f"{self.base_url}/completions"
body = {
"model": self.model,
"prompt": f"{parts.system}\n\n{parts.story}",
"temperature": temperature,
"max_tokens": max_tokens,
"stream": True,
"stream_options": dict(STREAM_OPTIONS),
}
else:
url = f"{self.base_url}/chat/completions"
body = {
"model": self.model,
"messages": [
{"role": "system", "content": parts.system},
{"role": "user", "content": parts.story + CHAT_CONTINUE_HINT},
],
"temperature": temperature,
"max_tokens": max_tokens,
"stream": True,
"stream_options": dict(STREAM_OPTIONS),
}
return url, body
@staticmethod
def _extract_chunk(payload: dict) -> str:
choices = payload.get("choices") or []
if not choices:
return ""
choice = choices[0]
# A chat stream uses `delta.content`, and a completion stream uses
# `text`. The non-stream fallbacks are `message.content` and `text`.
delta = choice.get("delta") or {}
return (
delta.get("content")
or choice.get("text")
or (choice.get("message") or {}).get("content")
or ""
)
@staticmethod
def _extract_reasoning(payload: dict) -> str:
"""Returns a reasoning model's thinking text.
OpenRouter normalizes it to `reasoning`, and DeepSeek-style servers use
`reasoning_content`.
"""
choices = payload.get("choices") or []
if not choices:
return ""
choice = choices[0]
delta = choice.get("delta") or {}
message = choice.get("message") or {}
return (
delta.get("reasoning")
or delta.get("reasoning_content")
or message.get("reasoning")
or message.get("reasoning_content")
or ""
)
async def generate(
self, parts: PromptParts, *, temperature: float, max_tokens: int
) -> AsyncIterator[tuple[str, str]]:
"""Yields `("text", chunk)` and `("reasoning", chunk)` pairs."""
if not self.model:
raise ProviderError("No model configured — set one in Settings.")
url, body = self._request(parts, temperature, max_tokens)
async for event in self._stream(url, body):
yield event
async def chat(
self, messages: list[dict], *, temperature: float, max_tokens: int
) -> AsyncIterator[tuple[str, str]]:
"""Runs a plain multi-turn chat, with no story framing and no context
assembly.
The method sends `[{"role", "content"}, ...]` straight to the endpoint.
The AI Chat scratchpad uses it, and the turn engine uses `generate()`.
"""
if not self.model:
raise ProviderError("No model configured — set one in Settings.")
if self.api_mode == "completion":
url = f"{self.base_url}/completions"
body = {
"model": self.model,
"prompt": flatten_messages(messages),
"temperature": temperature,
"max_tokens": max_tokens,
"stream": True,
"stream_options": dict(STREAM_OPTIONS),
}
else:
url = f"{self.base_url}/chat/completions"
body = {
"model": self.model,
"messages": messages,
"temperature": temperature,
"max_tokens": max_tokens,
"stream": True,
"stream_options": dict(STREAM_OPTIONS),
}
async for event in self._stream(url, body):
yield event
async def _stream(self, url: str, body: dict) -> AsyncIterator[tuple[str, str]]:
"""Runs the shared SSE request for `generate()` and `chat()`.
The method POSTs a streaming request, yields `("text", chunk)` and
`("reasoning", chunk)` pairs, and logs the exchange.
"""
# Re-checked on every request, not only when the endpoint was saved: a
# hostname that resolved to a LAN address yesterday can resolve
# somewhere else today, and a database row can be edited by hand.
reason = endpoints.rejection_reason(url)
if reason:
raise ProviderError(f"This endpoint can't be used — {reason}.")
log = debuglog.start_entry(url, self.model, body)
received: list[str] = []
try:
async with httpx.AsyncClient(
timeout=self._timeout(), verify=tlstrust.ssl_context()
) as client:
async with client.stream("POST", url, json=body, headers=self._headers()) as resp:
if resp.status_code != 200:
detail = (await resp.aread()).decode(errors="replace")[:500]
raise ProviderError(self._friendly_http_error(resp.status_code, detail))
# Some servers ignore `stream=true` and return one plain
# JSON body, so buffer the non-SSE lines to fall back to.
saw_sse = False
raw_lines: list[str] = []
async for line in resp.aiter_lines():
if not line.startswith("data:"):
if not saw_sse:
raw_lines.append(line)
continue
saw_sse = True
data = line[5:].strip()
if data == "[DONE]":
debuglog.finish_entry(
log, response="".join(received), usage=self.last_usage
)
return
try:
payload = json.loads(data)
except ValueError:
continue
self._record_usage(payload)
reasoning = self._extract_reasoning(payload)
if reasoning:
yield "reasoning", reasoning
chunk = self._extract_chunk(payload)
if chunk:
received.append(chunk)
yield "text", chunk
if not saw_sse:
body_text = "\n".join(raw_lines).strip()
try:
payload = json.loads(body_text)
except ValueError:
raise ProviderError(
"AI endpoint returned neither an SSE stream nor JSON: "
+ body_text[:200]
)
self._record_usage(payload)
reasoning = self._extract_reasoning(payload)
if reasoning:
yield "reasoning", reasoning
chunk = self._extract_chunk(payload)
if chunk:
received.append(chunk)
yield "text", chunk
if not received:
raise ProviderError(
"AI endpoint returned a response with no text: "
+ body_text[:200]
)
debuglog.finish_entry(log, response="".join(received), usage=self.last_usage)
except httpx.ConnectError as exc:
error = f"Could not connect to {self.base_url} — is the AI server running?"
debuglog.finish_entry(log, response="".join(received), error=error)
raise ProviderError(error) from exc
except httpx.TimeoutException as exc:
debuglog.finish_entry(log, response="".join(received), error="Timed out")
raise ProviderError("The AI endpoint timed out.") from exc
except httpx.HTTPError as exc:
debuglog.finish_entry(log, response="".join(received), error=str(exc))
raise ProviderError(f"Request to AI endpoint failed: {exc}") from exc
except (ProviderError, GeneratorExit, BaseException) as exc:
status = "cancelled" if isinstance(exc, GeneratorExit) else str(exc)
debuglog.finish_entry(log, response="".join(received), error=status)
raise
async def complete(
self, system: str, user: str, *, temperature: float = 0.3, max_tokens: int = 400
) -> str:
"""Runs a single non-streaming completion, for background calls such as
summarization.
Unlike `generate()`, this adds no story-continuation framing.
"""
if not self.model:
raise ProviderError("No model configured — set one in Settings.")
if self.api_mode == "completion":
url = f"{self.base_url}/completions"
body = {
"model": self.model,
"prompt": f"{system}\n\n{user}",
"temperature": temperature,
"max_tokens": max_tokens,
"stream": False,
}
else:
url = f"{self.base_url}/chat/completions"
body = {
"model": self.model,
"messages": [
{"role": "system", "content": system},
{"role": "user", "content": user},
],
"temperature": temperature,
"max_tokens": max_tokens,
"stream": False,
}
# Same check as `_stream`: every outbound request re-tests the
# endpoint, so no path reaches an address the policy refuses.
reason = endpoints.rejection_reason(url)
if reason:
raise ProviderError(f"This endpoint can't be used — {reason}.")
log = debuglog.start_entry(url, self.model, body)
try:
async with httpx.AsyncClient(
timeout=self._timeout(), verify=tlstrust.ssl_context()
) as client:
resp = await client.post(url, json=body, headers=self._headers())
except httpx.HTTPError as exc:
debuglog.finish_entry(log, error=str(exc))
raise ProviderError(f"Request to AI endpoint failed: {exc}") from exc
if resp.status_code != 200:
error = self._friendly_http_error(resp.status_code, resp.text[:500])
debuglog.finish_entry(log, error=error)
raise ProviderError(error)
try:
payload = resp.json()
except ValueError as exc:
debuglog.finish_entry(log, error="Invalid JSON response")
raise ProviderError("AI endpoint returned invalid JSON.") from exc
self._record_usage(payload)
text = self._extract_chunk(payload)
debuglog.finish_entry(log, response=text, usage=self.last_usage)
return text.strip()
async def embed(self, texts: list[str]) -> list[list[float]]:
"""POSTs to /v1/embeddings. Here `self.model` is the embedding model."""
if not self.model:
raise ProviderError("No embedding model configured — set one in Settings.")
url = f"{self.base_url}/embeddings"
body = {"model": self.model, "input": texts}
# Same check as `_stream`: every outbound request re-tests the
# endpoint, so no path reaches an address the policy refuses.
reason = endpoints.rejection_reason(url)
if reason:
raise ProviderError(f"This endpoint can't be used — {reason}.")
log = debuglog.start_entry(url, self.model, body)
try:
async with httpx.AsyncClient(
timeout=self._timeout(EMBED_READ_TIMEOUT), verify=tlstrust.ssl_context()
) as client:
resp = await client.post(url, json=body, headers=self._headers())
except httpx.HTTPError as exc:
debuglog.finish_entry(log, error=str(exc))
raise ProviderError(f"Embedding request failed: {exc}") from exc
if resp.status_code != 200:
error = self._friendly_http_error(resp.status_code, resp.text[:500])
debuglog.finish_entry(log, error=error)
raise ProviderError(error)
try:
data = resp.json().get("data", [])
vectors = [item["embedding"] for item in sorted(data, key=lambda d: d.get("index", 0))]
except (ValueError, KeyError, TypeError) as exc:
debuglog.finish_entry(log, error="Malformed embeddings response")
raise ProviderError("AI endpoint returned malformed embeddings.") from exc
if len(vectors) != len(texts):
debuglog.finish_entry(log, error="Embedding count mismatch")
raise ProviderError("AI endpoint returned the wrong number of embeddings.")
debuglog.finish_entry(log, response=f"{len(vectors)} vectors × {len(vectors[0]) if vectors else 0} dims")
return vectors
def _friendly_http_error(self, status: int, detail: str) -> str:
"""The message a reader sees when the endpoint answers with an error.
M8 rewrote two of these. They were the last user-facing text describing
a hosted deployment this build does not have: a 401 advised checking an
API key, and a 429 explained a shared free tier's daily cap. There is no
API key field — M2 removed it with the cloud providers — and no shared
tier, so both sent a reader looking for a setting that does not exist.
Ollama's own 401 and 429 mean something else entirely.
"""
if status == 401:
return (
"The endpoint refused the request as unauthorized (HTTP 401). "
"An ordinary local Ollama does not require authentication — "
f"check that {self.base_url} is the endpoint you meant. {detail}"
)
if status == 404:
return (
f"Endpoint or model not found (HTTP 404). Check the endpoint URL and that "
f"model '{self.model}' exists. {detail}"
)
if status == 429:
return (
"The endpoint is refusing further requests for now (HTTP 429). "
"Wait a moment and try again."
)
return f"AI endpoint returned HTTP {status}: {detail}"