Celia Chen b89d91f6ff feat: support oneOf and allOf in tool input schemas (#24118) ...

## Why

Some connector golden schemas use JSON Schema composition keywords
beyond `anyOf`, specifically top-level or nested `oneOf` and `allOf`.
Codex currently needs to preserve those shapes when parsing MCP tool
input schemas so connector tools do not lose valid schema structure
during normalization.

To prevent an increased Responses API error rate, this PR will be merged
after the Responses API supports top-level `oneOf`/`allOf`.

## What Changed

- Adds `oneOf` and `allOf` support to `JsonSchema`, matching the
existing `anyOf` handling.
- Traverses `oneOf` and `allOf` anywhere schema children are visited,
including sanitization, definition reachability, description stripping,
and deep schema compaction.
- Adds a final large-schema compaction pass that prunes schema objects
containing `anyOf`, `oneOf`, or `allOf` to `{}` if earlier compaction
passes still leave the schema over budget.

## Validation
Golden schema token validation over `2,025` schemas under
`golden_schemas`, all parsed successfully. Token count is `o200k_base`
over compact JSON from `parse_tool_input_schema`.

| Percentile | Before PR | After oneOf/allOf | After pruning |
|---|---:|---:|---:|
| p0 | 9 | 9 | 9 |
| p10 | 63 | 64 | 64 |
| p25 | 86 | 87 | 87 |
| p50 | 125 | 128 | 128 |
| p75 | 203 | 206 | 206 |
| p90 | 327 | 333 | 333 |
| p95 | 460 | 473 | 473 |
| p99 | 763 | 779 | 779 |
| max | 891 | 955 | 955 |

Totals:

| Parser state | Total tokens |
|---|---:|
| Before PR | 345,713 |
| After oneOf/allOf | 352,686 |
| After pruning | 352,686 |

The pruning column matches the oneOf/allOf column for this corpus
because no parsed compact golden schema remains over the `4,000`
compact-byte budget after the earlier compaction passes.

b89d91f6ff · 2026-06-08 21:41:05 +00:00

History

..

json_schema_policy

feat: support oneOf and allOf in tool input schemas (#24118)

2026-06-08 21:41:05 +00:00