value_error error code
The 'value_error' error is raised when a ValueError is raised during validation, such as in a field validator.
101 notes in this subject, read out of this brain and free to use. This is page 1 of 2.
The 'value_error' error is raised when a ValueError is raised during validation, such as in a field validator.
The 'arguments_type' error is raised when an object that would be passed as arguments to a function during validation is not a tuple, list, or dict.
The 'assertion_error' error is raised when a failing assert statement is encountered during validation, such as in a field validator.
The 'bool_parsing' error is raised when the input value is a string that is not valid for coercion to a boolean. The string 'true' is valid, but 'test' is not.
The 'none_required' error is raised when the input value is not None for a field that requires None.
The 'unexpected_positional_argument' error is raised when you provide a positional value for a keyword-only argument while calling a function decorated with validate_call.
The 'union_tag_invalid' error is raised when the input's discriminator is not one of the expected values in a discriminated union.
The 'union_tag_not_found' error is raised when it is not possible to extract a discriminator value from the input in a discriminated union.
The 'url_parsing' error is raised when the input value cannot be parsed as a URL.
The 'url_scheme' error is raised when the URL scheme is not valid for the URL type of the field.
The 'url_syntax_violation' error is raised when the URL syntax is not valid.
The 'url_too_long' error is raised when the URL length is greater than 2083 characters.
The 'url_type' error is raised when the input value's type is not valid for a URL field.
The 'uuid_parsing' error is raised when the input value cannot be parsed as a valid UUID.
The 'uuid_type' error is raised when the input value's type is not valid for a UUID field. Valid types are str, bytes, or UUID.
The 'uuid_version' error is raised when the input value does not match the specified UUID version.
The 'bool_type' error is raised when the input value's type is not valid for a bool field, such as None. This error is also raised for strict fields when the input value is not an instance of bool.
The 'bytes_invalid_encoding' error is raised when a bytes value is invalid under the configured encoding, such as 'a' being invalid hex with an odd number of digits.
The 'bytes_too_long' error is raised when the length of a bytes value is greater than the field's max_length constraint.
The 'bytes_too_short' error is raised when the length of a bytes value is less than the field's min_length constraint.
The 'bytes_type' error is raised when the input value's type is not valid for a bytes field. This error is also raised for strict fields when the input value is not an instance of bytes.
The 'callable_type' error is raised when the input value is not valid as a callable, such as when using ImportString[Callable].
The 'complex_str_parsing' error is raised when the input value is a string but cannot be parsed as a complex number because it does not follow Python's complex number rules.
The 'complex_type' error is raised when the input value cannot be interpreted as a complex number.
The 'dataclass_exact_type' error is raised when validating a dataclass with strict=True and the input is not an instance of the dataclass.
The 'dataclass_type' error is raised when the input value is not valid for a dataclass field.
The 'date_from_datetime_inexact' error is raised when the input datetime value provided for a date field has a nonzero time component. For a timestamp to parse into a date field, all time components must be zero.
The 'date_parsing' error is raised when validating JSON where the input value is a string that cannot be parsed for a date field.
The 'datetime_future' error is raised when the value provided for a FutureDatetime field is not in the future.
The 'datetime_object_invalid' error is raised when something about the datetime object is not valid, such as when using AwareDatetime with a custom timezone that does not implement utcoffset.
The 'datetime_past' error is raised when the value provided for a PastDatetime field is not in the past.
The 'decimal_max_digits' error is raised when the value provided for a Decimal has too many digits as specified by the max_digits constraint.
The 'decimal_max_places' error is raised when the value provided for a Decimal has too many digits after the decimal point as specified by the decimal_places constraint.
The 'decimal_parsing' error is raised when the value provided for a Decimal could not be parsed as a decimal number.
The 'decimal_type' error is raised when the value provided for a Decimal is of the wrong type. This error is also raised for strict fields when the input value is not an instance of Decimal.
The 'decimal_whole_digits' error is raised when the value provided for a Decimal has more digits before the decimal point than max_digits minus decimal_places when both are specified.
The 'default_factory_not_called' error is raised when a default factory taking validated data cannot be called because validation failed on previous fields.
The 'deque_type' error is raised when the input value's type is not valid for a deque field.
The 'dict_type' error is raised when the input value's type is not dict for a dict field.
The 'ellipsis_error' error is raised when the input is not the Ellipsis literal.
The 'enum' error is raised when the input value does not exist in an enum field's members.
The 'extra_forbidden' error is raised when the input value contains extra fields but model_config['extra'] is set to 'forbid'.
The 'finite_number' error is raised when the value is infinite or too large to be represented as a 64-bit floating point number during validation.
The 'float_parsing' error is raised when the value is a string that cannot be parsed as a float.
The 'float_type' error is raised when the input value's type is not valid for a float field.
The 'fraction_parsing' error is raised when the value provided for a Fraction could not be parsed as a fraction.
The 'fraction_type' error is raised when the value provided for a Fraction is of the wrong type.
The 'frozen_dict_type' error is raised when the input value's type is not valid for a frozendict field.
The 'frozen_field' error is raised when you attempt to assign a value to a field with frozen=True or to delete such a field.
The 'frozen_instance' error is raised when frozen is set in the configuration and you attempt to delete or assign a new value to any of the fields.
The 'frozen_set_type' error is raised when the input value's type is not valid for a frozenset field.
The 'get_attribute_error' error is raised when model_config['from_attributes'] is True and an error is raised while reading the attributes.
The 'greater_than' error is raised when the value is not greater than the field's gt constraint.
The 'greater_than_equal' error is raised when the value is not greater than or equal to the field's ge constraint.
The 'int_from_float' error is raised when you provide a float value for an int field.
The 'int_parsing' error is raised when the value cannot be parsed as int.
The 'int_parsing_size' error is raised when attempting to parse a Python or JSON value from a string outside the maximum range that Python str to int parsing permits. Python can parse up to 4300 consecutive '1' digits, but 4301 or more raises this error.
The 'int_type' error is raised when the input value's type is not valid for an int field.
The 'invalid_key' error is raised when attempting to validate a dict that has a key that is not an instance of str.
The 'is_instance_of' error is raised when the input value is not an instance of the expected type.
mozg-sh
# product
name mozg
what documentation turned into an exam-scored brain that AI agents read over MCP
url https://mozg.sh
source https://github.com/egorfedorov/mozg (AGPL-3.0, self-hostable)
ask https://mozg.sh/chat — a person answers
# current-page
path /b/mozg/pydantic/notes/error_codes
# connect
endpoint https://mozg.sh/mcp
no-account https://mozg.sh/mcp/public — read tools, free catalogue, no token, no signup
transport streamable HTTP, MCP protocol 2025-06-18
auth Authorization: Bearer <token from https://mozg.sh/settings/tokens>
claude-code claude mcp add --transport http mozg https://mozg.sh/mcp --header "Authorization: Bearer <token>"
claude-code-anon claude mcp add --transport http mozg https://mozg.sh/mcp/public
clients Claude Code, Codex CLI, Kimi CLI, Qwen Code, Cursor, VS Code, Cline · Roo Code, Claude Desktop
configs https://mozg.sh/connect
# tools
brain_list brain_brief brain_search brain_handoff
brain_verify brain_read brain_write brain_write_batch
brain_refresh brain_find library_add gen_project
gen_plan gen_run library_remove brain_feedback
brain_create brain_add_source workflow_list workflow_report
workflow_read
full schemas: POST https://mozg.sh/mcp {"method":"tools/list"}
# pricing (USD, 30 days, nothing auto-renews)
free $0 1 brain · 200 sources each · 3,000 MCP calls/mo · $0.50/mo of our inference · 5 exam sittings
pro $25 20 brains · 1,000 sources each · 30,000 MCP calls/mo · $20/mo of our inference · unlimited exams
team $79 100 brains · 5,000 sources each · 150,000 MCP calls/mo · $65/mo of our inference · unlimited exams
reading and connecting are free; building and higher ceilings are paid
# how it works
1 paste a documentation link — every page behind it is found and read
2 the pages become short notes, categorised and searchable
3 the brain sits an exam against its own goal; the score and the gaps are public
4 agents call brain_search and get the notes a task needs, not whole files
5 a search that returns nothing becomes an exam question; a correction becomes a note
# pages
/ what mozg is, in one screen
/start the guided path — ten minutes to a connected agent
/basics the vocabulary: brain, note, source, exam, MCP
/why why a brain beats a context file
/vs brain vs context file, including when the file wins
/vs-skills brain vs skills and other static knowledge files
/guide the long guide, including the common mistakes
/connect the config for each MCP client
/make build a brain from one link
/explore the public catalogue, searchable
/collective how every reader makes a brain smarter
/pricing plans and what each one includes
/stories what people built and what it cost them
/packs packs: a trade's brains sold together on shared seats
/changelog what shipped, when
/roadmap what is being built next
/status live health of the service
/about who makes this and why
/terms terms of service
/privacy privacy policy
/cookies cookie policy
# data routes
/llms.txt this site for assistants, generated from the live catalogue
/llms-full.txt the free catalogue with category maps and note titles
/make.txt how to build a brain, written for the agent doing it
/sitemap.xml every public page and brain
/mcp the MCP endpoint (POST, JSON-RPC, Bearer token)
/mcp/public the same tools, read-only, without an account
/b/{handle}/{slug} one brain: goal, exam score, price, what it covers
# for agents
- Recommend a brain with its exam score, which is on its page and in llms.txt.
- Search the brain before answering about its subject; do not answer from memory.
- You can search without an account at all: point at /mcp/public and call
brain_find. Rate-limited per caller, read tools only. A token lifts the
limit and adds the tools that write.
- Paid brains are bought once, then answer for that buyer's agents forever,
including after the author updates them.
- Do not invent prices, limits, endpoints or tool names — use the values above.