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fix(anthropic): normalize cross-provider tool-call IDs (#37756)

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Anthropic's API rejects `tool_use`/`tool_result` IDs that don't match
`^[a-zA-Z0-9_-]+$` with a 400. When a conversation thread is replayed
across providers — e.g. a user switches a running thread from Kimi (via
Fireworks) to Claude — the prior turns carry tool-call IDs minted by the
other provider (Kimi emits `functions.write_todos:0`, whose `.` and `:`
are invalid), and the request fails. Tool-call IDs are now normalized to
an Anthropic-compatible form during request formatting, with the
original `tool_use.id` and its paired `tool_use_id` mapped identically
so they stay linked.
This commit is contained in:
Mason Daugherty
2026-05-28 16:13:57 -04:00
committed by GitHub
parent 80ca60014f
commit 1a5403d848
2 changed files with 237 additions and 29 deletions
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117
libs/partners/anthropic/langchain_anthropic/chat_models.py
View File

@@ -4,6 +4,7 @@ from __future__ import annotations
import copy
import datetime
import hashlib
import json
import re
import warnings
@@ -237,6 +238,51 @@ def _format_image(url: str) -> dict:
)
_TOOL_CALL_ID_PATTERN = re.compile(r"^[a-zA-Z0-9_-]+$")
"""Anthropic requires `tool_use`/`tool_result` IDs to match this pattern."""
def _normalize_tool_call_id(tool_call_id: str | None) -> str | None:
"""Map a tool-call ID to an Anthropic-compatible form if needed.
Anthropic rejects `tool_use`/`tool_result` IDs that don't match
`^[a-zA-Z0-9_-]+$`. IDs minted by other providers can violate this when a
thread is replayed across providers (e.g. Fireworks/Kimi emits
`functions.write_todos:0`, whose `.` and `:` are invalid). Valid IDs are
returned unchanged; invalid ones are hashed deterministically so that a
rewritten `tool_use.id` and its paired `tool_use_id` resolve to the same
value, both within a request and across turns.
Empty and `None` IDs are passed through unchanged so that a genuinely
malformed request surfaces as a clear error from Anthropic rather than
being masked by a synthesized ID.
Args:
tool_call_id: The tool-call ID to normalize.
Returns:
The original ID if it is empty, `None`, or already valid; otherwise a
deterministic Anthropic-compatible replacement.
"""
if not tool_call_id or _TOOL_CALL_ID_PATTERN.match(tool_call_id):
return tool_call_id
digest = hashlib.sha256(tool_call_id.encode()).hexdigest()
return f"toolu_{digest[:24]}"
def _normalize_block_tool_use_id(block: dict) -> dict:
"""Return `block` with its `tool_use_id` normalized, if it carries one.
Mirrors `_normalize_tool_call_id` for `tool_result`-style content blocks so
that a `tool_use_id` arriving pre-structured (e.g. on a `ToolMessage` whose
content is already a list of `tool_result` blocks) stays consistent with its
paired, normalized `tool_use.id`. A no-op for already-valid IDs.
"""
if "tool_use_id" in block:
return {**block, "tool_use_id": _normalize_tool_call_id(block["tool_use_id"])}
return block
def _merge_messages(
messages: Sequence[BaseMessage],
) -> list[SystemMessage | AIMessage | HumanMessage]:
@@ -272,7 +318,7 @@ def _merge_messages(
tool_result: dict = {
"type": "tool_result",
"content": tool_content,
"tool_use_id": curr.tool_call_id,
"tool_use_id": _normalize_tool_call_id(curr.tool_call_id),
"is_error": curr.status == "error",
}
if cache_ctrl:
@@ -516,7 +562,7 @@ def _format_messages(
type="tool_use",
name=block["name"],
input=args,
id=block["id"],
id=cast("str", _normalize_tool_call_id(block["id"])),
)
if caller := block.get("caller"):
tool_use_block["caller"] = caller
@@ -595,24 +641,30 @@ def _format_messages(
):
# Tool search results with tool_reference blocks
content.append(
{
k: v
for k, v in block.items()
if k
in (
"type",
"content",
"tool_use_id",
"cache_control",
)
},
_normalize_block_tool_use_id(
{
k: v
for k, v in block.items()
if k
in (
"type",
"content",
"tool_use_id",
"cache_control",
)
},
),
)
elif block["type"] == "tool_result":
# Regular tool results that need content formatting
tool_content = _format_messages(
[HumanMessage(block["content"])],
)[1][0]["content"]
content.append({**block, "content": tool_content})
content.append(
_normalize_block_tool_use_id(
{**block, "content": tool_content},
),
)
elif block["type"] in (
"code_execution_tool_result",
"bash_code_execution_tool_result",
@@ -622,19 +674,21 @@ def _format_messages(
"web_fetch_tool_result",
):
content.append(
{
k: v
for k, v in block.items()
if k
in (
"type",
"content",
"tool_use_id",
"is_error", # for mcp_tool_result
"cache_control",
"retrieved_at", # for web_fetch_tool_result
)
},
_normalize_block_tool_use_id(
{
k: v
for k, v in block.items()
if k
in (
"type",
"content",
"tool_use_id",
"is_error", # for mcp_tool_result
"cache_control",
"retrieved_at", # for web_fetch_tool_result
)
},
),
)
else:
content.append(block)
@@ -662,8 +716,13 @@ def _format_messages(
for block in content
if cast("dict", block)["type"] == "tool_use"
]
# `tool_use_ids` are already normalized via the branches above, so
# compare against the normalized tool-call ID to avoid emitting a
# duplicate `tool_use` block when the original ID was rewritten.
missing_tool_calls = [
tc for tc in message.tool_calls if tc["id"] not in tool_use_ids
tc
for tc in message.tool_calls
if _normalize_tool_call_id(tc["id"]) not in tool_use_ids
]
cast("list", content).extend(
_lc_tool_calls_to_anthropic_tool_use_blocks(missing_tool_calls),
@@ -2224,7 +2283,7 @@ def _lc_tool_calls_to_anthropic_tool_use_blocks(
type="tool_use",
name=tool_call["name"],
input=tool_call["args"],
id=cast("str", tool_call["id"]),
id=cast("str", _normalize_tool_call_id(tool_call["id"])),
)
for tool_call in tool_calls
]

149
libs/partners/anthropic/tests/unit_tests/test_chat_models.py
View File

@@ -24,11 +24,13 @@ from pytest import CaptureFixture, MonkeyPatch
from langchain_anthropic import ChatAnthropic
from langchain_anthropic.chat_models import (
_TOOL_CALL_ID_PATTERN,
_create_usage_metadata,
_format_image,
_format_messages,
_is_builtin_tool,
_merge_messages,
_normalize_tool_call_id,
_thinking_in_params,
convert_to_anthropic_tool,
)
@@ -767,6 +769,153 @@ def test__format_messages_with_tool_calls() -> None:
]
def test__normalize_tool_call_id() -> None:
# Already-valid IDs (including native Anthropic and OpenAI styles) pass
# through unchanged.
for valid in ("1", "toolu_01abcDEF-_", "call_Ao02pnFYXD6GN1yzc0uXPsvF"):
assert _normalize_tool_call_id(valid) == valid
# Empty and None IDs pass through so a malformed request surfaces a clear
# error from Anthropic rather than a synthesized ID.
assert _normalize_tool_call_id("") == ""
assert _normalize_tool_call_id(None) is None
# Foreign IDs with characters Anthropic rejects (e.g. Fireworks/Kimi's
# `functions.write_todos:0`) are rewritten to a compatible form.
invalid = "functions.write_todos:0"
normalized = _normalize_tool_call_id(invalid)
assert normalized is not None
assert normalized != invalid
assert _TOOL_CALL_ID_PATTERN.match(normalized)
# Deterministic + idempotent: same input always maps to the same output.
assert _normalize_tool_call_id(invalid) == normalized
assert _normalize_tool_call_id(normalized) == normalized
# Distinct invalid IDs map to distinct replacements (no collision that
# would break multi-tool turns).
other = _normalize_tool_call_id("functions.read_file:1")
assert other != normalized
def test__format_messages_normalizes_cross_provider_tool_call_ids() -> None:
"""A `tool_use.id` and its paired `tool_use_id` must normalize identically.
Reproduces the Fireworks/Kimi -> Anthropic 400 from replaying a thread whose
tool-call IDs were minted by another provider.
"""
bad_id = "functions.write_todos:0"
ai = AIMessage(
"",
tool_calls=[{"name": "write_todos", "id": bad_id, "args": {"todos": []}}],
)
tool = ToolMessage("done", tool_call_id=bad_id)
_, formatted = _format_messages([HumanMessage("hi"), ai, tool])
tool_use = formatted[1]["content"][0]
tool_result = formatted[2]["content"][0]
assert tool_use["type"] == "tool_use"
assert tool_result["type"] == "tool_result"
# The rewritten IDs are valid and still reference each other.
assert _TOOL_CALL_ID_PATTERN.match(tool_use["id"])
assert tool_use["id"] == tool_result["tool_use_id"]
assert tool_use["id"] == _normalize_tool_call_id(bad_id)
def test__format_messages_normalizes_prestructured_tool_result_id() -> None:
"""A `ToolMessage` whose content is already `tool_result` blocks is covered.
This shape bypasses the `tool_call_id` normalization in `_merge_messages` and
flows through the `tool_result` content branch, so its `tool_use_id` must
still be normalized to match the paired `tool_use.id`.
"""
bad_id = "functions.write_todos:0"
ai = AIMessage(
"",
tool_calls=[{"name": "write_todos", "id": bad_id, "args": {"todos": []}}],
)
tool = ToolMessage(
[{"type": "tool_result", "tool_use_id": bad_id, "content": "done"}],
tool_call_id=bad_id,
)
_, formatted = _format_messages([HumanMessage("hi"), ai, tool])
tool_use = formatted[1]["content"][0]
tool_result = formatted[2]["content"][0]
assert tool_use["id"] == tool_result["tool_use_id"]
assert tool_use["id"] == _normalize_tool_call_id(bad_id)
def test__format_messages_normalizes_inline_tool_use_block() -> None:
"""An invalid ID on an inline `tool_use` content block is normalized.
Covers the v1-compat destination where tool calls are stored as content
blocks rather than the `tool_calls` attribute, paired with a `ToolMessage`.
"""
bad_id = "functions.search:2"
ai = AIMessage(
[{"type": "tool_use", "name": "search", "id": bad_id, "input": {"q": "x"}}],
)
tool = ToolMessage("result", tool_call_id=bad_id)
_, formatted = _format_messages([HumanMessage("hi"), ai, tool])
tool_use = formatted[1]["content"][0]
tool_result = formatted[2]["content"][0]
assert _TOOL_CALL_ID_PATTERN.match(tool_use["id"])
assert tool_use["id"] == tool_result["tool_use_id"]
def test__format_messages_dedupes_overlapping_normalized_tool_use() -> None:
"""An invalid ID shared by a `tool_use` block and `tool_calls` yields one block.
Guards the dedup branch: `tool_use_ids` are normalized, so the comparison
against the (also normalized) tool-call ID must not re-emit a duplicate block.
"""
bad_id = "functions.write_todos:0"
ai = AIMessage(
[{"type": "tool_use", "name": "write_todos", "id": bad_id, "input": {"a": 1}}],
tool_calls=[{"name": "write_todos", "id": bad_id, "args": {"a": 1}}],
)
_, formatted = _format_messages([HumanMessage("hi"), ai])
tool_use_blocks = [b for b in formatted[1]["content"] if b["type"] == "tool_use"]
assert len(tool_use_blocks) == 1
assert _TOOL_CALL_ID_PATTERN.match(tool_use_blocks[0]["id"])
def test__format_messages_normalizes_distinct_ids_independently() -> None:
"""Multiple distinct invalid IDs in one turn stay distinct and correctly paired."""
id_a = "functions.write_todos:0"
id_b = "functions.read_file:1"
ai = AIMessage(
"",
tool_calls=[
{"name": "write_todos", "id": id_a, "args": {}},
{"name": "read_file", "id": id_b, "args": {}},
],
)
tool_a = ToolMessage("a", tool_call_id=id_a)
tool_b = ToolMessage("b", tool_call_id=id_b)
_, formatted = _format_messages([HumanMessage("hi"), ai, tool_a, tool_b])
tool_uses = formatted[1]["content"]
results = formatted[2]["content"]
assert tool_uses[0]["id"] == _normalize_tool_call_id(id_a)
assert tool_uses[1]["id"] == _normalize_tool_call_id(id_b)
assert tool_uses[0]["id"] != tool_uses[1]["id"]
# Each result still pairs with its own tool_use.
assert {r["tool_use_id"] for r in results} == {
tool_uses[0]["id"],
tool_uses[1]["id"],
}
def test__format_tool_use_block() -> None:
# Test we correctly format tool_use blocks when there is no corresponding tool_call.
message = AIMessage(