# bedrock_call.py
import copy
import re
from typing import Any, Dict, List
from jsonschema import Draft202012Validator
from mcp.types import Tool
# Bedrock naming rules: 1–64 chars, letters/numbers/underscore/hyphen only
_NAME_PATTERN = re.compile(r"^[A-Za-z0-9_-]{1,64}$")
def prune_schema(schema: Dict[str, Any]) -> Dict[str, Any]:
"""Recursively prune forbidden keys from a schema."""
forbidden_keys = {"anyOf", "$schema", "$ref"}
conversion = {"$defs": "description"}
pruned = copy.deepcopy(schema)
def _prune(node: Any):
if isinstance(node, dict):
for key in list(node.keys()):
if key in forbidden_keys:
del node[key]
elif key in conversion:
node[conversion[key]] = str(node.pop(key))
else:
_prune(node[key])
elif isinstance(node, list):
for item in node:
_prune(item)
_prune(pruned)
return pruned
def _sanitize_name(name: str) -> str:
# Replace invalid chars with underscore and trim length
clean = re.sub(r"[^A-Za-z0-9_-]", "_", name)
return clean[:64]
def validate_schema(schema: Dict[str, Any]) -> None:
"""Raise if schema is not valid Draft 2020-12."""
Draft202012Validator.check_schema(schema)
def convert_tool_format(tools: List[Tool], model: str) -> Dict[str, List[Dict[str, Any]]]:
"""Convert MCP tools into a Bedrock Draft 2020-12-compliant toolConfig."""
# For other models, we need to convert tools to the Bedrock format
converted = []
for tool in tools:
# 1. Sanitize and validate name
name = _sanitize_name(tool.name)
# 2. Build full schema including meta-schema pointer
full_schema = {
"$schema": "https://json-schema.org/draft/2020-12/schema",
**tool.inputSchema, # Preserve $defs, anyOf, etc.
}
# 3. Validate locally
validate_schema(full_schema)
# 4. Assemble Bedrock toolSpec
converted.append(
{
"toolSpec": {
"name": name,
"description": tool.description or "",
"inputSchema": {"json": full_schema},
}
}
)
if "amazon.nova" in model:
converted = [prune_schema(item) for item in converted]
return {"tools": converted}
