microsoft / microsoft/mcp

JSON Schema 2020-12 tool contracts

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#2,974 1 comment 0 reactions 1 assignee View on GitHub

@alzimmermsft is already working on this.

Since Jul 8, 2026.

enhancement server-Azure.Mcp tools-Core
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C#
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Description

Make tool schemas compatible with the expanded schema model and prepare for richer tool definitions.

Work items:
1. Review current schema generation in the command/tool loader pipeline.
2. Upgrade input-schema generation so it can express composition and references when needed.
3. Add support for output schemas where a tool benefits from structured results.
4. Ensure any validator limits schema depth and execution time.
5. Explicitly block unsafe external `$ref` dereference behavior.
6. Select a small number of high-value tools as pilots for richer schemas before broad rollout.

Acceptance criteria:
- Existing tools continue to work with the new schema model.
- One or more pilot tools demonstrate richer schema expressiveness.
- Validation remains bounded and safe.

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