From: Bart Louwers <redacted>
Date: Tue, 30 Dec 2025 21:13:49 +0000 (+0100)
Subject: docs : document that JSON Schema is not available to model when using response_format... 
X-Git-Tag: upstream/0.0.7599~13
X-Git-Url: https://git.djapps.eu/?a=commitdiff_plain;h=6e0c8cbc40c4abf49e5c52f0f51267c2afdfc053;p=pkg%2Fggml%2Fsources%2Fllama.cpp

docs : document that JSON Schema is not available to model when using response_format  (#18492)

* Document unsupported JSON Schema annotations

Add note about unsupported JSON Schema annotations.

* Update README.md

* Update README.md

* Update README.md
---

diff --git a/grammars/README.md b/grammars/README.md
index daac7f4d..dcd28648 100644
--- a/grammars/README.md
+++ b/grammars/README.md
@@ -150,6 +150,9 @@ You can use GBNF grammars:
     - in CLI, with [examples/json_schema_to_grammar.py](../examples/json_schema_to_grammar.py)
     - in JavaScript with [json-schema-to-grammar.mjs](../tools/server/public_legacy/json-schema-to-grammar.mjs) (this is used by the [server](../tools/server)'s Web UI)
 
+> [!NOTE]
+> The JSON schema is only used to constrain the model output and is not injected into the prompt. The model has no visibility into the schema, so if you want it to understand the expected structure, describe it explicitly in your prompt. This does not apply to tool calling, where schemas are injected into the prompt.
+
 Take a look at [tests](../tests/test-json-schema-to-grammar.cpp) to see which features are likely supported (you'll also find usage examples in https://github.com/ggml-org/llama.cpp/pull/5978, https://github.com/ggml-org/llama.cpp/pull/6659 & https://github.com/ggml-org/llama.cpp/pull/6555).
 
 ```bash