Module composition 

Language-neutral executable tool-composition contract.

A composition run is a tiny program over already-typed tool bindings. The runtime must expose it as a parent run with child tool operations, not as an opaque “execute code” blob, so policy, transcript, replay, and host approval surfaces can keep reasoning about each child call normally.

Structs

BindingManifest

Stable prompt-visible manifest for a composition run.

BindingManifestEntry

Prompt-visible description of one callable binding.

BindingManifestOptions

BindingPolicyStatus

Policy metadata attached to a manifest binding.

ClosureCompositionToolHost

Dispatches every binding call to a caller-supplied Harn closure.

CompositionChildCall

Child tool call made by a composition snippet. This is intentionally close to AgentEvent::ToolCall, but includes parent-run correlation and the policy/annotation context the composition executor used when deciding whether the call was allowed.

CompositionChildResult

Terminal or intermediate result for a child binding operation. Consumers should pair this with the corresponding CompositionChildCall to recover the policy annotations and requested side-effect level for the operation.

CompositionExecutionLimits

CompositionExecutionReport

CompositionExecutionRequest

CompositionRunEnvelope

Identity and policy envelope for one composition run.

CompositionToolOutput

StaticCompositionToolHost

Enums

BindingPolicyDisposition

Policy disposition for a binding projected into a composition manifest.

CompositionFailureCategory

Stable failure taxonomy for a composition run. Tool-level failures stay on CompositionChildResult; this classifies why the parent composition itself failed or stopped.

Constants

BINDING_MANIFEST_SCHEMA_VERSION

COMPOSITION_EXECUTION_SCHEMA_VERSION

Traits

CompositionToolHost

Functions

binding_manifest_from_tool_surface

Build a binding manifest from a Harn tool registry, MCP tools/list payload, or provider-native tool array.

binding_manifest_hash

Stable digest for a binding manifest value. Producers should build manifests with deterministic object key order before hashing.

composition_crystallization_trace

composition_report_events

composition_search_examples

composition_snippet_hash

Stable digest for the prompt-visible snippet body.

composition_typescript_declarations

execute_harn_composition

Execute a read-only Harn-native composition snippet against a manifest.

register_composition_builtins