You can build this yourself.
Most teams shouldn't.
Each tool below is good at what it's good at. None of them are an agent runtime. That's the gap.
Six dimensions where DIY agent infra falls over.
Pick a row. This is the work you are signing up for if you build it yourself — and what a2a cloud gives you out of the box.
What each tool leaves you to build.
LangGraph / LangChain
orchestration librarygood at: Graph-shaped agent logic. Great for in-process flows.
- No service identity. Agents aren't deployable as standalone services.
- No scoped grant primitive between graph nodes.
- No AgentCard, no MCP surface, no /tasks protocol surface.
- Receipts are your problem.
CrewAI / AutoGen / swarm libs
multi-agent frameworkgood at: Role-shaped collaboration loops. Fast to prototype.
- Same in-process trap — agents are objects, not services.
- Tools share the host process's filesystem and creds.
- No discovery standard. No marketplace path.
- Audit is whatever you logged.
DIY FastAPI + auth
hand-built servicegood at: Full control. Familiar shape.
- You will rebuild AgentCard, MCP, file grants, receipts, replay.
- Tenanted auth, key rotation, sandboxing are not freebies.
- Every team will rebuild it differently.
- Switching from prototype to governed prod is a rewrite.
Cloud Run / Fargate / Lambda
managed computegood at: Solid container or function runtime. Good autoscale.
- Compute primitives. No agent primitives.
- No standard for skills, schemas, AgentCards, pricing.
- Workspace + grant + handoff are above this layer.
- MCP/A2A interop is your integration job.
Kubernetes + service mesh
platform plumbinggood at: Tenant isolation, mTLS, policy — at the network layer.
- Network identity ≠ agent identity. No AgentCard.
- No file grants, no receipts, no replay surface.
- Months of platform work before the first agent ships.
- You're still inventing a deploy DX on top.
Internal home-grown
the inevitable Notion docgood at: Shaped to your stack. Maybe.
- Three teams will build three of them.
- None will have receipts or grant primitives.
- Hiring will require explaining a snowflake.
- External agents can't speak your protocol.
A runtime that ships with agent primitives, not just compute.
The differences below aren't individual features. Each is a primitive the runtime owns — so the same building blocks work across teams, agents, and external partners.
runtime owns
Standardize the runtime before every team builds a different one.
The same dynamic that produced Kubernetes, Docker, OAuth, and service meshes is happening for agents. Build it once, on a standard. Or build it three times, by accident, in three teams.