> ## Documentation Index
> Fetch the complete documentation index at: https://docs.app.useharmonia.xyz/llms.txt
> Use this file to discover all available pages before exploring further.

# Strands Agents SDK

> Native request-scoped cognition with deterministic host authority.

## How Harmonia uses it

`HarmoniaCoordinator` selects one `SpecialistDefinition` from validated host state. It is a project-owned coordinator, not a free-running model router. `LocalStrandsTeamRuntime` validates the typed input, activates preloaded method provenance, projects runtime constraints and constructs a fresh `strands.Agent`.

The agent receives a `BedrockModel`, explicit system prompt, only the permitted tools, `AuthorityHooks` and a Pydantic `structured_output_model`. `invoke_async()` returns the structured result and usage metrics. `callback_handler=None` suppresses token callbacks; `retry_strategy=None` prevents unbounded SDK retries. The host separately controls bounded provider and schema repair.

## Hooks

| Native hook            | Enforcement                                                              |
| ---------------------- | ------------------------------------------------------------------------ |
| `BeforeModelCallEvent` | Paid gate, turn bound and actual-request hash                            |
| `BeforeToolCallEvent`  | Allowed tool set, exact request binding and one-shot research permission |
| `AfterToolCallEvent`   | Tool evidence capture and typed handoff handling                         |

Skills are host-preloaded text. There are no registered filesystem skill-loader tools. Tool-free registrations remain tool-free except for the native structured-output cognition mechanism.

## State and authority

Each call owns new messages, hooks and mutable state. The output is returned under the definition's state key. The worker validates and persists it before changing a stage. Human waits, retries, external-effect claims and receipts survive in DynamoDB independently of the runtime session.

## Evidence status

`agent/harmonia_agent/agents.py`, `team_runtime.py`, `runtime_instructions.py` and `workflow.py` define this boundary. Local tests exercise real Strands request/hook contracts with test model doubles. Authenticated Bedrock and AgentCore invocation remains pending live verification.