Files
pallas/tests/test_mantle_shims.py
Robert Helewka d8703a1ad6 🐾 fix(mantle): stop installing the unproven 20k max_tokens clamp
The fine-grained-tool-streaming opt-out is what actually fixes the
"Streaming completed but tool call never finished" crash loop: under
that beta an output cutoff mid-tool_use ends the stream without
content_block_stop, fast-agent's tool tracker leaves the block open,
and _raise_for_incomplete_anthropic_tools raises a RuntimeError that
bypasses the graceful stop_reason=max_tokens path and burns the retry
ladder. That shim costs no output length and is kept.

The companion max_tokens clamp is not. Its 20 000 ceiling was an
empirical observation, never a documented Mantle limit, and
re-investigation could not establish what enforces it: fast-agent
carries no 20 000 default anywhere (the matching TASK_BUDGET_MIN_TOKENS
is a validation floor for a different, unconfigured feature), no model
overlay is configured, and ModelDatabase reports
max_output_tokens=128000 for opus-4-8. Installing it would cement a
ceiling we cannot prove and silently truncate turns that might
otherwise complete.

install_max_tokens_clamp() is left in place, unwired, so it can be
re-enabled if the limit is ever confirmed.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
2026-08-05 21:55:10 -04:00

215 lines
8.7 KiB
Python

"""Tests for pallas.mantle_shims.
These tests exercise the module in isolation: they do not hit the network
and do not require fast-agent to be configured. They do, however, import
fast-agent so that the monkeypatch targets exist — so fast-agent-mcp must
be installed in the environment running pytest.
"""
from __future__ import annotations
import pytest
from pallas import mantle_shims
# ── is_mantle_base_url ───────────────────────────────────────────────────────
@pytest.mark.parametrize(
"url,expected",
[
("https://bedrock-mantle.us-east-1.api.aws/anthropic", True),
("https://bedrock-mantle.ca-central-1.api.aws/anthropic", True),
("https://api.anthropic.com", False),
("https://example.com/bedrock", False),
("", False),
(None, False),
],
)
def test_is_mantle_base_url(url: str | None, expected: bool) -> None:
assert mantle_shims.is_mantle_base_url(url) is expected
# ── install_wire_name_prefix ─────────────────────────────────────────────────
def test_install_wire_name_prefix_registers_prefixed_ids() -> None:
from fast_agent.llm.model_database import ModelDatabase
from fast_agent.llm.provider_types import Provider
mantle_shims.install_wire_name_prefix()
for fa_name, wire_name in mantle_shims.MANTLE_WIRE_NAMES.items():
key = (Provider.ANTHROPIC, ModelDatabase.normalize_model_name(fa_name))
assert ModelDatabase._PROVIDER_WIRE_MODEL_NAMES.get(key) == wire_name
def test_install_wire_name_prefix_is_idempotent() -> None:
mantle_shims.install_wire_name_prefix()
mantle_shims.install_wire_name_prefix() # must not raise
# Second call leaves the same mapping in place.
from fast_agent.llm.model_database import ModelDatabase
from fast_agent.llm.provider_types import Provider
key = (Provider.ANTHROPIC, ModelDatabase.normalize_model_name("claude-opus-4-7"))
assert ModelDatabase._PROVIDER_WIRE_MODEL_NAMES[key] == "anthropic.claude-opus-4-7"
# ── _strip_tool_use_caller ───────────────────────────────────────────────────
def test_strip_tool_use_caller_removes_caller_key() -> None:
blocks = [
{"type": "tool_use", "id": "t1", "name": "foo", "input": {}, "caller": None},
{"type": "text", "text": "hello"},
{"type": "tool_use", "id": "t2", "name": "bar", "input": {}}, # no caller
]
result = mantle_shims._strip_tool_use_caller(blocks)
assert "caller" not in result[0]
assert result[1] == {"type": "text", "text": "hello"}
assert "caller" not in result[2]
def test_strip_tool_use_caller_is_idempotent() -> None:
blocks = [{"type": "tool_use", "id": "t1", "name": "foo", "input": {}, "caller": None}]
mantle_shims._strip_tool_use_caller(blocks)
mantle_shims._strip_tool_use_caller(blocks) # second pass must be a no-op
assert "caller" not in blocks[0]
def test_strip_tool_use_caller_ignores_non_dict_blocks() -> None:
# Anthropic SDK model objects are sometimes passed instead of dicts;
# the helper must leave those untouched.
class Sentinel:
type = "tool_use"
s = Sentinel()
blocks = [s]
mantle_shims._strip_tool_use_caller(blocks)
assert blocks[0] is s # unchanged
# ── install_tool_use_caller_strip ────────────────────────────────────────────
def test_install_tool_use_caller_strip_patches_converter() -> None:
from fast_agent.llm.provider.anthropic.multipart_converter_anthropic import (
AnthropicConverter,
)
mantle_shims.install_tool_use_caller_strip()
# The patched deserialize must strip caller from replayed tool_use dicts.
channels: dict[str, list[dict]] = {"assistant_raw": []}
# We can't easily stub the original's internal behaviour, so just
# verify the patch is in place by round-tripping a destination list
# through _append_server_tool_channel_blocks, which we *know* ends by
# calling our strip helper on `destination`.
destination: list[dict] = [
{"type": "tool_use", "id": "t1", "name": "foo", "input": {}, "caller": None},
]
AnthropicConverter._append_server_tool_channel_blocks(None, destination)
assert "caller" not in destination[0]
def test_install_tool_use_caller_strip_is_idempotent() -> None:
mantle_shims.install_tool_use_caller_strip()
mantle_shims.install_tool_use_caller_strip() # must not raise or re-wrap
# ── install_fine_grained_tool_streaming_opt_out ──────────────────────────────
def test_fine_grained_beta_opt_out() -> None:
from fast_agent.llm.provider.anthropic.llm_anthropic import AnthropicLLM
mantle_shims.install_fine_grained_tool_streaming_opt_out()
# The patched method never touches self, so a bare object suffices.
stub = object()
assert AnthropicLLM.supports_direct_anthropic_beta(stub, "fine_grained_tool_streaming") is False
# Every other beta keeps the base-class answer (True).
assert AnthropicLLM.supports_direct_anthropic_beta(stub, "interleaved_thinking") is True
assert AnthropicLLM.supports_direct_anthropic_beta(stub, "long_context") is True
def test_fine_grained_beta_opt_out_is_idempotent() -> None:
mantle_shims.install_fine_grained_tool_streaming_opt_out()
mantle_shims.install_fine_grained_tool_streaming_opt_out() # must not re-wrap
from fast_agent.llm.provider.anthropic.llm_anthropic import AnthropicLLM
assert (
AnthropicLLM.supports_direct_anthropic_beta(object(), "fine_grained_tool_streaming")
is False
)
# ── install_max_tokens_clamp ─────────────────────────────────────────────────
@pytest.mark.parametrize(
"initial,expected",
[
(128000, mantle_shims.MANTLE_MAX_OUTPUT_TOKENS), # over the ceiling → clamped
(None, mantle_shims.MANTLE_MAX_OUTPUT_TOKENS), # unset → pinned to ceiling
(4096, 4096), # under the ceiling → untouched
],
)
def test_max_tokens_clamp(
monkeypatch: pytest.MonkeyPatch, initial: int | None, expected: int
) -> None:
from fast_agent.llm.provider.anthropic.llm_anthropic import AnthropicLLM
from fast_agent.types import RequestParams
# Stub the underlying initializer, then force a fresh wrap around it.
monkeypatch.setattr(
AnthropicLLM,
"_initialize_default_params",
lambda self, kwargs: RequestParams(maxTokens=initial),
)
monkeypatch.setattr(mantle_shims, "_max_tokens_clamp_installed", False)
mantle_shims.install_max_tokens_clamp()
params = AnthropicLLM._initialize_default_params(object(), {})
assert params.maxTokens == expected
def test_max_tokens_clamp_is_idempotent() -> None:
mantle_shims.install_max_tokens_clamp()
mantle_shims.install_max_tokens_clamp() # must not raise or re-wrap
# ── maybe_install ────────────────────────────────────────────────────────────
_INSTALLER_NAMES = [
("install_wire_name_prefix", "wire"),
("install_tool_use_caller_strip", "tool_use"),
("install_fine_grained_tool_streaming_opt_out", "beta_opt_out"),
("install_max_tokens_clamp", "max_tokens"),
]
def _patch_installers(monkeypatch: pytest.MonkeyPatch) -> list[str]:
calls: list[str] = []
for attr, label in _INSTALLER_NAMES:
monkeypatch.setattr(
mantle_shims, attr,
lambda label=label: calls.append(label),
)
return calls
def test_maybe_install_installs_when_mantle(monkeypatch: pytest.MonkeyPatch) -> None:
calls = _patch_installers(monkeypatch)
installed = mantle_shims.maybe_install("https://bedrock-mantle.us-east-1.api.aws/anthropic")
assert installed is True
# "max_tokens" is intentionally absent: the 20 000 clamp is not installed
# by default because the ceiling was never confirmed. See install_all().
assert calls == ["wire", "tool_use", "beta_opt_out"]
def test_maybe_install_noop_for_non_mantle(monkeypatch: pytest.MonkeyPatch) -> None:
calls = _patch_installers(monkeypatch)
assert mantle_shims.maybe_install("https://api.anthropic.com") is False
assert mantle_shims.maybe_install(None) is False
assert mantle_shims.maybe_install("") is False
assert calls == []