strands.vended_interventions.cedar.cedar_authorization

Cedar authorization intervention handler.

TypeAndId

A Cedar entity identifier with ‘type’ and ‘id’ keys.

PrincipalResolver

Resolves a principal from invocation_state. Return None to deny (fail-closed).

ContextEnricher

Injects extra fields into context.session. Receives {‘tool_name’, ‘tool_input’, ‘invocation_state’}.

CedarAuthorization

class CedarAuthorization(InterventionHandler)

Defined in: src/strands/vended_interventions/cedar/cedar_authorization.py:71

Cedar authorization intervention handler.

Evaluates Cedar policies before each tool call. Each tool maps to a Cedar action, with context structured as \{input: <tool_args>, session: \{hour_utc, call_count, ...}}.

Call counts are persisted to agent.state under the key "cedar-authorization" so they survive handler recreation and are included in session snapshots.

.. note:: Each handler instance is scoped to a single agent. Sharing one instance across multiple agents will cause rate-limit counts to leak between them.

Example::

cedar = CedarAuthorization( policies=‘permit(principal, action == Action::“search”, resource);’ ) agent = Agent(interventions=[cedar], tools=[search_tool])

on_error

@property
def on_error() -> OnError

Defined in: src/strands/vended_interventions/cedar/cedar_authorization.py:95

What to do when this handler throws.

__init__

def __init__(*,
             policies: str,
             tools: list[ToolDefinition] | None = None,
             entities: list[dict[str, Any]] | str | None = None,
             schema: str | None = None,
             principal: TypeAndId | None = None,
             principal_resolver: PrincipalResolver | None = None,
             context_enricher: ContextEnricher | None = None,
             on_error: OnError = "throw") -> None

Defined in: src/strands/vended_interventions/cedar/cedar_authorization.py:99

Initialize the Cedar authorization handler.

Arguments:

• policies - Inline Cedar policy text or path to a .cedar file.
• tools - MCP tool definitions for auto schema generation.
• entities - Entity data as inline list, JSON string, or path to .json file.
• schema - Cedar schema as inline text or path to .cedarschema file.
• principal - Static principal identity.
• principal_resolver - Dynamic principal resolver from invocation_state.
• context_enricher - Callback to inject extra fields into context.session.
• on_error - Error handling mode for user callback exceptions.

before_tool_call

def before_tool_call(event: BeforeToolCallEvent,
                     **kwargs: Any) -> Proceed | Deny

Defined in: src/strands/vended_interventions/cedar/cedar_authorization.py:155

Evaluate Cedar policy before tool execution.

reload

def reload() -> None

Defined in: src/strands/vended_interventions/cedar/cedar_authorization.py:230

Reload policies/entities/schema from disk. Validates before committing.

reset_call_counts

def reset_call_counts(agent: Agent | None = None) -> None

Defined in: src/strands/vended_interventions/cedar/cedar_authorization.py:250

Clear all rate-limit call counters.

Arguments:

• agent - If provided, also clears persisted counts from agent.state.