This page provides an overview of the systems and services that are supported by the AI Agent, as well as some fundamental definitions. Please refer to the other pages in this space and the full API specification for more information.
Benefits of a Multi-agent System
- Each agent is minimal in scope, trained or prompted to perform a constrained set of reasoning steps.
- Communication between agents is explicit, typed, and protocol-bound (A2A for reasoning-to-reasoning, MCP for reasoning-to-tools).
- Agents can be reasoners, tool providers, or hybrids, but agents are not tools — a reasoning agent may call multiple tools over its lifecycle without being reducible to a single function.
- The orchestration layer enforces stateless reasoning agents with ephemeral lifetimes; all intermediate state is persisted centrally, not in the agent process.
Limitations of monolithic LLM systems:
Limitations of monolithic LLM systems:
- Context collapse: The more roles and tools a single agent handles, the higher the prompt entropy and the lower the reasoning reliability.
- Coupling between reasoning and tooling: Single agents tend to entangle reasoning logic with tool invocation logic, making both brittle.
- Scaling bottlenecks: Expanding capability requires re-prompting, re-tuning, or increasing context windows, rather than attaching specialized, isolated capabilities.
Orchestrator
The Orchestrator is the central intelligence layer of the AI Agent system that interacts with users and manages the flow of conversations or tasks. It does not perform specialized work itself but delegates to the appropriate Expert. It is a stateless API layer per tenant namespace, with pluggable persistence for state (Postgres, Redis, etc.), ensuring data isolation and horizontal scaling.Orchestrator is the only component aware of the following key details:
| Thread state | A canonical, persistent record of all agent calls, tool calls, intermediate outputs, and contextual injections. |
| Client interface | User-facing API surface for initiating threads, injecting additional context, and retrieving results. |
| Expert registry | Dynamic discovery and registration of MCP-compliant agents (Experts). Maintains metadata, capabilities, and versioning. |
| Execution graph construction | Translates a user request into an execution plan across multiple reasoning agents and tools. |
| Guardrails | Runtime validation of requests and responses, with policy-driven rejection or escalation. Includes hard constraints (schema validation, allowed tool sets) and soft constraints (model-based harmful content detection). |
Reasoning Service
A Reasoning Service is any service that:- Accepts an A2A Task Object.
- Produces a valid A2A Task result or sub-task request.
- Implements domain-specific reasoning over one or more tools.
- Idempotent and able to be replayed given the same task input.
- May be stateful or stateless depending on the goals of the Agent reasoning service.
Experts = MCP + Reasoning Service
An Expert is a modular, domain-specific agent that performs specific tasks. Each Expert encapsulates one or more tools, APIs, or models specific to its function.- The model context protocol (MCP) layer exposes tool metadata (
list_tools) and execution (execute_tool) in standard MCP schema. - The reasoning layer decides when and how to call these tools, potentially chaining multiple tool calls before returning.
- Some Experts expose a
responsepseudo-tool to allow direct end-user replies without Orchestrator post-processing (useful for short-circuiting when an intermediate agent has terminal output).
| Benefits | |
|---|---|
| Encapsulation | Tool protocol logic is separate from reasoning prompts/weights. |
| Replaceability | Swap MCP server or reasoning layer independently. |
| Parallelism | Multiple Experts can execute in parallel if dependencies are resolved. |
| Heterogeneous reasoning | Reasoning can be LLM-based, symbolic, or programmatic without changing the orchestration contract. |
Tool Providers
Tool Providers may be:- Pure MCP servers (e.g., FHIR data fetcher, medical coding API).
- Wrappers over non-MCP services with schema translation.
- Hybrid providers that extend MCP spec for advanced capabilities (streaming responses, structured multimodal input).
- Implement
list_toolsandexecute_toolendpoints. - Must be callable by any agent.
- Are stateless (i.e., stored in memory) with tool execution being in the relevant target system.
Dataflow
1
Client → Orchestrator
Thread initiation with task payload and optional context injections.
2
Orchestrator → Reasoning Service
A2A request with task definition, constraints, available Experts.
3
Reasoning Service → Tool Provider
MCP tool calls to retrieve or mutate domain data.
4
Reasoning Service → Orchestrator
A2A return with results, new sub-task requests, or terminal output.
5
Orchestrator → Client
Final aggregated result or streamed partials.
Why This Works in Practice
| Protocol separation | A2A for agent coordination, MCP for tool execution. Minimizes protocol scope creep. |
| Stateless compute | Reasoning services scale horizontally with no warm-state concerns. |
| Strong typing & validation | All cross-service messages are JSON Schema–validated. |
| Replaceable layers | MCP servers, reasoning services, and Orchestrator can evolve independently. |
| Developer autonomy | Third parties can author Experts without touching orchestration code—just expose MCP and wrap in a reasoning layer. |
Please contact us if you need more information about the Corti Agentic Framework.