Reference

The look-it-up section: signatures, parameters, defaults, attributes and what raises what. The conceptual pages explain why a mechanism exists — this one says what it takes. The public surface is two namespaces. charter holds tools, markers, transforms and errors. charter.auth holds credentials and OAuth, all of it, with nothing re-exported from charter, so each name has exactly one import path and the inventory below says which. Everything outside those two is internal and free to move between releases: charter.execution in particular is the runtime, not an API.

The pages

Page	Covers
Tool	the object one endpoint compiles to
Factories	`api_key_tool_factory`, `oauth_tool_factory`, and the builder they return
Schema markers	`Path`, `Query`, `Body`, `Format`, `Mode`, `Case`, `KeyCase`, `TransportOverride`
Semantic types	the shapes a model fills in before a transform encodes them
Protobuf types	the `google.protobuf` well-known types as Pydantic models
Credentials	providers, and the subject machinery for many end users
OAuth	servers, clients, and the two steps of obtaining a grant
Envelopes and pagination	failure inside a 200, and where the cursor lives
Transforms	the registry, and the ten built-in transforms
Response handling	trimming a payload before the model reads it
Observability and egress	what a call cost, and what the model can see
Errors	the exception hierarchy
Configuration	`configure()`, the tuning settings, the environment
Command line	`python -m charter.mcp`

`version`

__version__: str

The installed version, as a string.

import charter

assert charter.__version__.count(".") == 2

Every public symbol

Generated from charter.__all__ and charter.auth.__all__ by scripts/generate_reference_docs.py, and checked by tests/test_reference_docs.py: a symbol added to the public surface without a reference entry turns the suite red.

Symbol	Import from	Page
`__version__`	`charter`	overview
`api_key_tool_factory`	`charter`	factories
`APIError`	`charter`	errors
`apply_transform`	`charter`	transforms
`AuthorizationRequest`	`charter.auth`	oauth
`Body`	`charter`	markers
`CalendarEvent`	`charter`	semantic-types
`CallbackProvider`	`charter.auth`	credentials
`CallCollector`	`charter`	observability
`CallSink`	`charter`	observability
`Case`	`charter`	markers
`CharterError`	`charter`	errors
`collecting`	`charter`	observability
`conflict_map`	`charter`	observability
`ConflictsWith`	`charter`	markers
`CredentialError`	`charter`	errors
`CredentialProvider`	`charter.auth`	credentials
`Credentials`	`charter.auth`	credentials
`current_subject`	`charter.auth`	credentials
`DeclarationError`	`charter`	errors
`decode_base64url`	`charter`	response-handling
`DocumentContent`	`charter`	semantic-types
`egress_map`	`charter`	observability
`EmailContent`	`charter`	semantic-types
`Envelope`	`charter`	envelopes-and-pagination
`EnvTokenProvider`	`charter.auth`	credentials
`FieldMask`	`charter`	protobuf-types
`FileContent`	`charter`	semantic-types
`Format`	`charter`	markers
`format_call_line`	`charter`	observability
`format_call_summary`	`charter`	observability
`format_conflicts`	`charter`	observability
`format_egress_map`	`charter`	observability
`get_transform`	`charter`	transforms
`Gloss`	`charter`	markers
`Grant`	`charter.auth`	oauth
`GRAPHQL_ENVELOPE`	`charter`	envelopes-and-pagination
`html_to_text`	`charter`	response-handling
`json_tokens`	`charter`	tool-discovery
`KeyCase`	`charter`	markers
`ListValue`	`charter`	protobuf-types
`Mode`	`charter`	markers
`NullValue`	`charter`	protobuf-types
`OAuth2Client`	`charter.auth`	oauth
`OAuth2Flow`	`charter.auth`	oauth
`OAuth2Server`	`charter.auth`	oauth
`oauth_tool_factory`	`charter`	factories
`OnRefresh`	`charter.auth`	oauth
`Pagination`	`charter`	envelopes-and-pagination
`partial_of`	`charter`	markers
`Path`	`charter`	markers
`PathCost`	`charter`	tool
`qualified_name`	`charter`	naming
`qualified_names`	`charter`	naming
`Query`	`charter`	markers
`register_transform`	`charter`	transforms
`ResponseHandler`	`charter`	response-handling
`schema_tokens`	`charter`	tool-discovery
`scopes_for`	`charter.auth`	oauth
`states_match`	`charter.auth`	oauth
`StaticTokenProvider`	`charter.auth`	credentials
`Struct`	`charter`	protobuf-types
`SubjectProvider`	`charter.auth`	credentials
`TokenEndpointAuthMethod`	`charter.auth`	oauth
`TokenGrant`	`charter.auth`	oauth
`Tool`	`charter`	tool
`ToolCall`	`charter`	observability
`ToolSession`	`charter`	tool-discovery
`ToolValidationError`	`charter`	errors
`TransformError`	`charter`	errors
`TransformRegistry`	`charter`	transforms
`TransformSpec`	`charter`	transforms
`TransportOverride`	`charter`	markers
`use_subject`	`charter.auth`	credentials
`Value`	`charter`	protobuf-types
`WireName`	`charter`	markers

Core

Schema

Authentication

Runtime

Operating

The pages

`version`

Every public symbol

​The pages

​__version__

​Every public symbol

The pages

`version`

Every public symbol