Documentation Index
Fetch the complete documentation index at: https://docs.dottxt.ai/llms.txt
Use this file to discover all available pages before exploring further.
Every structured output provider supports a different subset of JSON Schema. This page shows where they diverge so you can pick the right one for your schema.
The table only includes features where at least one provider differs. Basic types, items, and $defs / $ref are supported by all four.
String constraints
| Feature | dottxt | OpenAI | Anthropic | Gemini |
|---|
minLength / maxLength | | | | |
pattern (regex) | | | | |
format | | | | |
Number constraints
| Feature | dottxt | OpenAI | Anthropic | Gemini |
|---|
minimum / maximum | | | | |
exclusiveMinimum / exclusiveMaximum | | | | |
multipleOf | | | | |
Array constraints
| Feature | dottxt | OpenAI | Anthropic | Gemini |
|---|
prefixItems (tuples) | | | | |
minItems / maxItems | | | | |
contains | | | | |
uniqueItems | | | | |
Multiple choices
| Feature | dottxt | OpenAI | Anthropic | Gemini |
|---|
enum | | | | |
Object constraints
| Feature | dottxt | OpenAI | Anthropic | Gemini |
|---|
| Optional fields | | | | |
additionalProperties (as schema) | | | | |
propertyNames | | | | |
patternProperties | | | | |
| Arbitrary JSON | | | | |
minProperties / maxProperties | | | | |
Composition
| Feature | dottxt | OpenAI | Anthropic | Gemini |
|---|
anyOf | | | | |
allOf | | | | |
oneOf | | | | |
not | | | | |
Conditionals
| Feature | dottxt | OpenAI | Anthropic | Gemini |
|---|
if / then / else | | | | |
dependentRequired | | | | |
dependentSchemas | | | | |
Schema reuse and recursion
| Feature | dottxt | OpenAI | Anthropic | Gemini |
|---|
| Recursive schemas | | | | |
Schema limits
| Limit | dottxt | OpenAI | Anthropic | Gemini |
|---|
| Nesting depth | None | 10 levels | None documented | None documented |
| Total properties | None | 5000 | None documented | None documented |
| Enum values | None | 1000 | None documented | None documented |
| Optional parameters | None | N/A | 24 per request | None documented |
| Union type parameters | None | N/A | 16 per request | None documented |
Handling of unsupported features
| Provider | Behavior |
|---|
| dottxt | Rejects the schema with an error specifying the unsupported construct |
| OpenAI | With strict: true, unsupported schemas return an API error |
| Anthropic | SDK strips unsupported constraints, adds them as text in field descriptions, validates response client-side |
| Gemini | Silently ignores unsupported properties |
Sources
Next steps
