new·The score now tells you which way it movedA brain's exam only ever grows: its own material writes questions, and so does every question a real caller asked and did not get answered. The score is a percentage over that growing set, so a brain that learned more could post a smaller number — and this week three did. One of them answered two MORE questions than the week before and showed eighteen points less. Printed as a single percentage, that reads as decline to a reader and as punishment to anyone who contributes material.all news →
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Pydantic

Answer questions about Pydantic as documented today: model definition and field types, validation and serialization, ConfigDict options, custom validators and serializers, JSON Schema generation, settings management, the API reference, and the validation error codes — v2 semantics, not v1.

1,481 notes across 4 brains · updated 2026-08-15 · trained 66%

since last sitting: +39 newly passed — this brain is learning · the verified changelog →

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$ claude mcp add --transport http mozg \
https://mozg.sh/mcp --header "Authorization: Bearer …"
> use mozg/pydantic — …
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Ask it things like

answers 39/59 on its latest exam
How do you create a basic Pydantic model with field validation?Model Definition & Inheritance✓
What are the valid values for the extra configuration option in ConfigDict?ConfigDict & Configuration✓
When writing a field validator, what exceptions should you raise to signal validation failure?Custom Validators & Serializers✓
What does the @validate_call decorator do?Decorators & Functional API✓
How do you create a discriminated union in Pydantic?Discriminated Unions✓
How does Pydantic parse a datetime field from an ISO 8601 string vs a Unix timestamp?Field Types & Validation✓
How do you generate JSON Schema from a Pydantic model?JSON Schema Generation✓
What does model_dump() return and what is the purpose of the include parameter?Serialization & Output✓

What is inside

asking this brain searches all 3
Pydantic · API referenceAnswer questions about the Pydantic API exactly as specified: BaseModel and its methods, Field, ConfigDict, the decorators, TypeAdapter and the rest — each with its signature and options.563 notes94%Pydantic · ConceptsAnswer questions about the Pydantic concepts: models and their config, fields and aliases, validators and serializers, dataclasses, JSON Schema, strict mode, type adapters, and how each standard and custom type is coerced.422 notes82%Pydantic · IntegrationsAnswer how Pydantic integrates with the documented tools: mypy, Hypothesis, devtools, datamodel-code-generator and the rest, with the configuration each one needs.69 notes96%

What it can answer

59 coverage checks
66%
Answers 39 of the exam's 59 questionsIt answers 39 questions, 39 more than last time, out of an exam that grew by 59.Nothing it used to answer has stopped working.
▲ConfigDict & Configuration5 / 6
▲Field Types & Validation4 / 6
▲JSON Schema Generation4 / 6
▲Serialization & Output4 / 6
▲Custom Validators & Serializers3 / 8
▲Error Codes & Validation Errors3 / 5
▲TypeAdapter & Advanced APIs3 / 4
✓Validation Modes & Strict Mode3 / 3
▲Decorators & Functional API2 / 3
▲JSON Parsing & Performance2 / 3
▲Model Definition & Inheritance2 / 3
▲Settings Management2 / 3
✓Aliases & Field Configuration1 / 1
▲Discriminated Unions1 / 2
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Attacks survived

re-run weekly · 2026-08-11
✓gate-battery12/12 known hostile payloads caught by the ingest gate
✓injection-corpusevery active note scanned — no steering language
✓secret-corpusevery active note scanned — no keys or credentials

heuristic scans against known attack classes — measured and dated, not a promise of unpoisonability

Inside

  • Three types of model validators · custom_validators
  • Accessing already validated data with ValidationInfo.data · custom_validators
  • Before validators defined with BeforeValidator or @field_validator · custom_validators
  • ValidatorFunctionWrapHandler import and usage · custom_validators
  • Model wrap validators take ModelWrapValidatorHandler · custom_validators
  • ValidationInfo argument in validators · custom_validators
  • Four types of field validators · custom_validators
  • After validators defined with AfterValidator or @field_validator · custom_validators
  • Plain validators terminate validation immediately · custom_validators
  • Wrap validators with ValidatorFunctionWrapHandler · custom_validators
  • Model after validators must return Self · custom_validators
  • Model before validators are classmethods taking Any · custom_validators
  • Raising validation errors with ValueError, AssertionError, or PydanticCustomError · custom_validators
  • Passing and accessing validation context · custom_validators

Licence

CC BY-NC-SA 4.0

Use it, copy it, build on it, with credit. Selling it is not allowed.