MCP may only partially meet integration needs, as you can only use what third-party servers expose.
Complexity, unpredictable capacity, and lack of detailed insight are common with remote A2A agents.
Integration issues, such as silent failures and mismatches between expected tool behaviors and actual results, can occur (example with Slack channel naming).
Sub agents process large raw datasets, returning only summaries to the host to keep context windows small and efficient.
Tool and agent context growth is a major scaling concern; context management and pruning strategies are critical for controlling cost and performance.
Prompt caching can reduce recurring context costs but must be managed carefully for optimal results.
Security and Compliance Considerations 30:04, 49:00
Authentication is enforced via headers, OAuth, or server-side policies; users log in and authorization is enforced based on their access.
For high-security/regulated environments (finance, defense), it is advised to run LLMs internally and avoid external MCP/A2A agents, using encryption, VPC isolation, and mutual TLS.
Security measures (e.g., whitelisting, managed endpoints) are not dictated by A2A/MCP protocols but by organizational posture.
Observability, Testing, and Human-in-the-Loop 61:17, 73:02
Observability is mostly custom-built; standard agent ops tools may not accommodate deeply composable or dynamic sub-agent architectures.
Testing uses demo accounts or synthetic data to avoid polluting live systems; agents interact with external tools in safe, non-production environments.
Human-in-the-loop functionality is being explored by modeling humans as agent "tools," allowing agents to message humans directly for business-critical input.
Comparisons and Best Practices: A2A, MCP, REST APIs 78:25
REST APIs suffice for systems entirely within your control, offering state management in the application layer rather than in agent contexts.
MCP/A2A provide state, context windows, and interoperability for more complex, distributed, or third-party integrated workflows.
When using MCP, care must be taken with tool selection and scope to avoid context bloat and unnecessary data exposure.
Advanced Topics: Orchestration, DAGs, and Prompt Strategies 81:08
Directed acyclic graphs (DAGs) are suggested for planning multi-step, branching workflows with dependencies among agents (similar to CI/CD pipelines).
Developers must guide orchestration and context slicing via prompt design and host agent logic; sub-agents generally receive concise, targeted tasks.
Experiments suggest that agent non-determinism and context management remain open challenges, impacting both reproducibility and cost.