Agent Orchestration & MCP
What happens when a task needs more than one tool, one model, or one system to complete.
6.6.1Definition
Orchestration coordinates multiple tools, sub-agents, or steps toward a single larger goal, managing sequencing, error handling, and hand-offs between them. MCP (Model Context Protocol) is an open standard that lets a model connect to external tools and data sources through a common interface, rather than each integration being built as a one-off.
6.6.2Why It Exists
As agentic systems (6.5) grow beyond a single tool call, coordinating multiple tools, sub-tasks, and error paths becomes its own engineering problem distinct from any individual tool call. MCP specifically exists to standardize how models discover and call external tools, so a new integration (a calendar, a database, a third-party API) can be added once and reused across any MCP-compatible agent, rather than rebuilding the connection logic for every model or application separately.
6.6.3Orchestration Patterns
| Pattern | Structure | Best fit |
|---|---|---|
| Single agent, many tools | One model with a broad tool set (6.5) | Most product features — simplest to reason about |
| Sequential sub-agents | Output of one agent step feeds the next | Multi-stage pipelines (research → draft → review) |
| Supervisor / worker | A coordinating agent delegates to specialized sub-agents | Complex tasks spanning distinct domains |
6.6.4Common Mistakes
- Over-engineering orchestration for a task a single agent with a few tools would handle, adding coordination complexity with no corresponding capability gain.
- No shared error-handling strategy across orchestrated steps, so a failure in one sub-agent silently corrupts or stalls the overall task.
- Building a custom, one-off tool-connection protocol instead of adopting an existing standard like MCP, duplicating integration work for every new tool and every new model.
6.6.5Best Practices
- Default to a single agent with well-defined tools; escalate to multi-agent orchestration only when a task genuinely spans distinct domains or requires specialization.
- Adopt MCP or an equivalent standard for tool connections rather than custom integration code per tool.
- Define explicit error and retry behavior at every hand-off point in an orchestrated pipeline.