|
| 1 | +"""Strict JSON schema transformation for tool definitions. |
| 2 | +
|
| 3 | +When model providers require `strict: true` on tool definitions, they also require |
| 4 | +`"additionalProperties": false` on every `object` type in the input schema. This module |
| 5 | +provides a utility to recursively apply that constraint. |
| 6 | +
|
| 7 | +Modeled after OpenAI's `_ensure_strict_json_schema`: |
| 8 | +https://github.com/openai/openai-python/blob/main/src/openai/lib/_pydantic.py |
| 9 | +""" |
| 10 | + |
| 11 | +import copy |
| 12 | +import logging |
| 13 | +from typing import Any |
| 14 | + |
| 15 | +logger = logging.getLogger(__name__) |
| 16 | + |
| 17 | + |
| 18 | +def ensure_strict_json_schema( |
| 19 | + schema: dict[str, Any], |
| 20 | + *, |
| 21 | + require_all_properties: bool = False, |
| 22 | +) -> dict[str, Any]: |
| 23 | + """Ensure a JSON schema conforms to strict tool use requirements. |
| 24 | +
|
| 25 | + Creates a deep copy of the schema and recursively: |
| 26 | + 1. Adds ``"additionalProperties": false`` to all ``object`` types that do not already define it |
| 27 | + 2. Optionally adds all properties to the ``required`` array (needed for OpenAI) |
| 28 | + 3. Handles ``$defs``, ``definitions``, ``anyOf``, ``allOf``, ``items``, and ``$ref`` |
| 29 | +
|
| 30 | + Args: |
| 31 | + schema: The JSON schema to process. A deep copy is made internally so the original is not mutated. |
| 32 | + require_all_properties: If True, set ``required`` to include all property keys. OpenAI strict mode |
| 33 | + requires this; Bedrock and Anthropic do not. |
| 34 | +
|
| 35 | + Returns: |
| 36 | + A new schema dict with strict-mode constraints applied. |
| 37 | + """ |
| 38 | + schema_copy = copy.deepcopy(schema) |
| 39 | + _apply_strict(schema_copy, root=schema_copy, require_all_properties=require_all_properties) |
| 40 | + return schema_copy |
| 41 | + |
| 42 | + |
| 43 | +def _apply_strict( |
| 44 | + schema: dict[str, Any], |
| 45 | + *, |
| 46 | + root: dict[str, Any], |
| 47 | + require_all_properties: bool, |
| 48 | +) -> None: |
| 49 | + """Recursively apply strict-mode constraints to a JSON schema in place. |
| 50 | +
|
| 51 | + Args: |
| 52 | + schema: The schema node to process (modified in place). |
| 53 | + root: The root schema, used for resolving ``$ref`` pointers. |
| 54 | + require_all_properties: If True, add all properties to ``required``. |
| 55 | + """ |
| 56 | + # Process $defs / definitions blocks |
| 57 | + for defs_key in ("$defs", "definitions"): |
| 58 | + defs = schema.get(defs_key) |
| 59 | + if isinstance(defs, dict): |
| 60 | + for def_schema in defs.values(): |
| 61 | + if isinstance(def_schema, dict): |
| 62 | + _apply_strict(def_schema, root=root, require_all_properties=require_all_properties) |
| 63 | + |
| 64 | + # Add additionalProperties: false to object types that lack it |
| 65 | + if schema.get("type") == "object" and "additionalProperties" not in schema: |
| 66 | + schema["additionalProperties"] = False |
| 67 | + |
| 68 | + # Process properties and optionally enforce required |
| 69 | + properties = schema.get("properties") |
| 70 | + if isinstance(properties, dict): |
| 71 | + if require_all_properties: |
| 72 | + schema["required"] = list(properties.keys()) |
| 73 | + |
| 74 | + for prop_schema in properties.values(): |
| 75 | + if isinstance(prop_schema, dict): |
| 76 | + _apply_strict(prop_schema, root=root, require_all_properties=require_all_properties) |
| 77 | + |
| 78 | + # Process array items |
| 79 | + items = schema.get("items") |
| 80 | + if isinstance(items, dict): |
| 81 | + _apply_strict(items, root=root, require_all_properties=require_all_properties) |
| 82 | + |
| 83 | + # Process anyOf variants |
| 84 | + any_of = schema.get("anyOf") |
| 85 | + if isinstance(any_of, list): |
| 86 | + for variant in any_of: |
| 87 | + if isinstance(variant, dict): |
| 88 | + _apply_strict(variant, root=root, require_all_properties=require_all_properties) |
| 89 | + |
| 90 | + # Process allOf variants |
| 91 | + all_of = schema.get("allOf") |
| 92 | + if isinstance(all_of, list): |
| 93 | + for entry in all_of: |
| 94 | + if isinstance(entry, dict): |
| 95 | + _apply_strict(entry, root=root, require_all_properties=require_all_properties) |
| 96 | + |
| 97 | + # Process oneOf variants |
| 98 | + one_of = schema.get("oneOf") |
| 99 | + if isinstance(one_of, list): |
| 100 | + for variant in one_of: |
| 101 | + if isinstance(variant, dict): |
| 102 | + _apply_strict(variant, root=root, require_all_properties=require_all_properties) |
| 103 | + |
| 104 | + # Resolve $ref combined with other keys by inlining the referenced schema |
| 105 | + ref = schema.get("$ref") |
| 106 | + if isinstance(ref, str) and len(schema) > 1: |
| 107 | + resolved = _resolve_ref(root, ref) |
| 108 | + if isinstance(resolved, dict): |
| 109 | + # Inline the resolved schema, giving priority to existing keys |
| 110 | + merged = {**copy.deepcopy(resolved), **schema} |
| 111 | + merged.pop("$ref", None) |
| 112 | + schema.clear() |
| 113 | + schema.update(merged) |
| 114 | + # Re-apply strict to the inlined schema |
| 115 | + _apply_strict(schema, root=root, require_all_properties=require_all_properties) |
| 116 | + |
| 117 | + |
| 118 | +def _resolve_ref(root: dict[str, Any], ref: str) -> dict[str, Any] | None: |
| 119 | + """Resolve a JSON Schema ``$ref`` pointer against the root schema. |
| 120 | +
|
| 121 | + Args: |
| 122 | + root: The root schema containing definitions. |
| 123 | + ref: A JSON pointer string (e.g., ``#/$defs/MyModel``). |
| 124 | +
|
| 125 | + Returns: |
| 126 | + The resolved schema dict, or None if resolution fails. |
| 127 | + """ |
| 128 | + if not ref.startswith("#/"): |
| 129 | + logger.warning("ref=<%s> | unexpected $ref format, skipping resolution", ref) |
| 130 | + return None |
| 131 | + |
| 132 | + path = ref[2:].split("/") |
| 133 | + current: Any = root |
| 134 | + for key in path: |
| 135 | + if not isinstance(current, dict) or key not in current: |
| 136 | + logger.warning("ref=<%s> | failed to resolve $ref path", ref) |
| 137 | + return None |
| 138 | + current = current[key] |
| 139 | + |
| 140 | + if not isinstance(current, dict): |
| 141 | + logger.warning("ref=<%s> | resolved to non-dict value", ref) |
| 142 | + return None |
| 143 | + |
| 144 | + return current |
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