Module: LittleGhost

Defined in:
lib/little_ghost.rb,
lib/little_ghost/run.rb,
lib/little_ghost/tool.rb,
lib/little_ghost/agent.rb,
lib/little_ghost/graph.rb,
lib/little_ghost/model.rb,
lib/little_ghost/swarm.rb,
lib/little_ghost/usage.rb,
lib/little_ghost/errors.rb,
lib/little_ghost/events.rb,
lib/little_ghost/lookup.rb,
lib/little_ghost/content.rb,
lib/little_ghost/message.rb,
lib/little_ghost/runtime.rb,
lib/little_ghost/sandbox.rb,
lib/little_ghost/session.rb,
lib/little_ghost/support.rb,
lib/little_ghost/version.rb,
lib/little_ghost/assembly.rb,
lib/little_ghost/path_set.rb,
lib/little_ghost/workflow.rb,
lib/little_ghost/execution.rb,
lib/little_ghost/workspace.rb,
lib/little_ghost/invocation.rb,
lib/little_ghost/mcp/client.rb,
lib/little_ghost/run_result.rb,
lib/little_ghost/run_context.rb,
lib/little_ghost/tools/shell.rb,
lib/little_ghost/agent/skills.rb,
lib/little_ghost/runtime/hook.rb,
lib/little_ghost/skills/skill.rb,
lib/little_ghost/stream_event.rb,
lib/little_ghost/ag_ui/adapter.rb,
lib/little_ghost/agent_builder.rb,
lib/little_ghost/configuration.rb,
lib/little_ghost/model_request.rb,
lib/little_ghost/models/target.rb,
lib/little_ghost/session_store.rb,
lib/little_ghost/tool_registry.rb,
lib/little_ghost/model_resolver.rb,
lib/little_ghost/model_response.rb,
lib/little_ghost/models/catalog.rb,
lib/little_ghost/models/details.rb,
lib/little_ghost/providers/base.rb,
lib/little_ghost/skills/catalog.rb,
lib/little_ghost/support/loader.rb,
lib/little_ghost/tool_execution.rb,
lib/little_ghost/agent/tool_loop.rb,
lib/little_ghost/execution_state.rb,
lib/little_ghost/instrumentation.rb,
lib/little_ghost/prompt_resolver.rb,
lib/little_ghost/agent/delegation.rb,
lib/little_ghost/assembly_builder.rb,
lib/little_ghost/providers/gemini.rb,
lib/little_ghost/providers/openai.rb,
lib/little_ghost/support/executor.rb,
lib/little_ghost/support/redactor.rb,
lib/little_ghost/tools/filesystem.rb,
lib/little_ghost/provider_registry.rb,
lib/little_ghost/providers/bedrock.rb,
lib/little_ghost/structured_output.rb,
lib/little_ghost/subagents/manager.rb,
lib/little_ghost/support/callbacks.rb,
lib/little_ghost/tools/write_todos.rb,
lib/little_ghost/assembly_execution.rb,
lib/little_ghost/model_capabilities.rb,
lib/little_ghost/support/sse_parser.rb,
lib/little_ghost/agent_interruptions.rb,
lib/little_ghost/providers/anthropic.rb,
lib/little_ghost/providers/vertex_ai.rb,
lib/little_ghost/support/http_client.rb,
lib/little_ghost/models/configuration.rb,
lib/little_ghost/subagents/agent_path.rb,
lib/little_ghost/subagents/definition.rb,
lib/little_ghost/unrestricted_sandbox.rb,
lib/little_ghost/models/catalog/source.rb,
lib/little_ghost/providers/open_router.rb,
lib/little_ghost/session_stores/memory.rb,
lib/little_ghost/tracing/open_telemetry.rb,
lib/little_ghost/models/catalog_snapshot.rb,
lib/little_ghost/providers/configuration.rb,
lib/little_ghost/support/content_capture.rb,
lib/little_ghost/agent/context_management.rb,
lib/little_ghost/support/class_attributes.rb,
lib/little_ghost/support/output_truncation.rb,
lib/little_ghost/support/cancellation_token.rb,
lib/little_ghost/providers/openai_compatible.rb,
lib/little_ghost/support/interruptible_stream.rb,
lib/little_ghost/providers/bedrock/http_client.rb,
lib/little_ghost/providers/bedrock/aws_protocol.rb,
lib/little_ghost/providers/gemini/catalog_source.rb,
lib/little_ghost/models/catalog/models_dev_source.rb,
lib/little_ghost/providers/bedrock/catalog_source.rb,
lib/little_ghost/session_stores/agent_core_memory.rb,
lib/little_ghost/providers/anthropic/catalog_source.rb,
lib/little_ghost/providers/open_router/catalog_source.rb,
lib/little_ghost/providers/bedrock/credential_resolver.rb,
lib/little_ghost/providers/vertex_ai/credential_resolver.rb

Overview

Build AI features with reusable agents and composable assemblies. LittleGhost can sit inside an existing Ruby system or support a dedicated AI service, keeping models, prompts, tools, sessions, streaming, and instrumentation behind a cohesive set of Ruby conventions.

A customer support agent can answer directly, use an application tool, or ask a specialist for research while the caller observes one run:

class ResearchAgent < LittleGhost::Agent
description "Researches difficult support questions"
model "openai:gpt-5.6-luna"
end

class CustomerSupportAgent < LittleGhost::Agent
description "Handles support requests"
model "openai:gpt-5.6-luna"
tools AccountTool
subagent ResearchAgent, kind: "research"
end

run = CustomerSupportAgent.ask("Why is transfer 481 still pending?")
run.completed? # => true
run.response   # => "Transfer 481 is waiting for the receiving bank."

Agent subclasses hold reusable behavior; Invocation objects carry one request, and Run objects own execution and cleanup. Assembly gives Agent, Workflow, Swarm, and Graph the same caller interface while each type owns a different coordination policy.

LittleGhost.configuration is process-wide unless LittleGhost.with_configuration supplies an execution-scoped replacement. Configuration is loaded lazily and snapshotted into a Runtime, so make application changes before the first agent runtime is built.

Defined Under Namespace

Modules: AGUI, Content, Events, ExecutionState, Instrumentation, Lookup, MCP, ModelInterface, Models, Providers, SessionStores, Skills, StructuredOutput, Subagents, Support, Tools, Tracing Classes: AbstractMethodError, AdapterLoadError, Agent, AgentBuilder, AgentFactory, AgentInterruptError, AgentInterruptions, Assembly, AssemblyBuilder, AssemblyDefinition, AssemblyError, AssemblyLimitError, AssemblyRoutingError, AssemblyStepTimeoutError, CancelledError, CleanupError, Configuration, ConfigurationError, ContextWindowOverflowError, CredentialError, DeadlineExceededError, Error, Execution, Graph, GraphBuilder, InvalidPromptTemplateError, Invocation, InvocationError, MalformedToolCallError, Message, MissingPromptLocalError, MissingPromptTemplateError, Model, ModelCapabilities, ModelRequest, ModelResolver, ModelResponse, OutputLimitError, PathSet, PromptResolver, PromptTemplateError, ProtocolError, ProviderError, ProviderRegistry, Run, RunContext, RunResult, Runtime, Sandbox, Session, SessionStore, StreamEvent, StructuredResult, StructuredResultError, Swarm, SwarmBuilder, Tool, ToolError, ToolExecution, ToolLoopError, ToolRegistry, TrustedPath, UnrestrictedSandbox, UnsupportedInputError, Usage, Workflow, WorkflowBuilder, Workspace

Constant Summary collapse

VERSION =

Current LittleGhost gem version.

"0.3.0"

Class Method Summary collapse

Class Method Details

.configuration ⇒ Object

The configuration active in the current execution context, falling back to the process-wide default.



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# File 'lib/little_ghost.rb', line 110

def configuration
  ExecutionState[:configuration] || (@configuration ||= Configuration.new)
end

.configure(&block) ⇒ Object

Opens the active Configuration for application setup and returns it.

Configuration files are loaded lazily when a runtime is first built, so make application-level changes before invoking an agent.



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# File 'lib/little_ghost.rb', line 118

def configure(&block)
  configuration.configure(&block)
end

.model_resolver ⇒ Object

Returns the model resolver owned by the active process configuration.



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# File 'lib/little_ghost.rb', line 123

def model_resolver = configuration.model_resolver

.with_configuration(configuration) ⇒ Object

Makes configuration current only while the block runs.

Execution state restores the previous configuration even when the block raises. Other execution contexts continue to see their own configuration.



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# File 'lib/little_ghost.rb', line 129

def with_configuration(configuration)
  ExecutionState.with(configuration:) { yield }
end