Explainer · Agentic AI architecture

Agentic infrastructure: the skills, tools, sandboxes and controls that let AI agents do real work safely

Most companies started with agents as a chat window and a few API calls. Agents that do real work need more underneath them: packaged know-how they can load when needed, tools with clear permissions, somewhere safe to run code, an identity for every action, and a record of what happened. This is the stack I design for teams moving agents from demos to production, layer by layer, with the standards that now exist for each.

ExplainerSumanta Mukhopadhyay10 min read7 sources
#ai#agents#architecture#mcp
EXPLAINER · EXPLAINER · AGENTIC AI ARCHITECTURE6 Nov 2026 · 19:40 GST

From chat window to infrastructure

An agent is a model in a loop: it reads a goal, decides on a step, calls a tool, looks at the result and repeats. That loop is easy to demo and hard to run at scale. Once agents touch real systems, the same questions come up in every company: how does the agent know how we do things here, what is it allowed to touch, where does its code run, whose authority is it acting on, and how do we find out what it did? Each question maps to a layer of infrastructure, and in 2026 most layers have an emerging standard.

Know-how
SkillsSKILL.md, scripts, referencesContext and memorywhat the agent knows now
Capabilities
ToolsMCP servers and APIsRegistryapproved servers and skills
Execution
Sandboxesisolated code and filesWorkflowsqueues, retries, approvals
Control
Identityagent and user, per actionPolicywhat each agent may doStoppause or revoke instantly
Evidence
Telemetryagent and tool spansEvaluationsdoes it still work?Costper agent and task
The agentic stack. Models sit beside it; the hard engineering is in these layers.

Skills: packaged know-how, loaded when needed

A skill is a folder with a SKILL.md file: a short name and description, then instructions, optionally alongside scripts, templates and reference documents1. The agent sees only the names and descriptions up front and reads the full skill when a task calls for it, so a company can give an agent hundreds of procedures without filling its context window1. Anthropic published the format as an open specification, and many agent tools now read the same files2.

For a business, skills are the natural home for "how we do things here": how to write a release note, how to reconcile a payment file, which checks to run before changing a database. They are also where tool automation becomes reliable. If a step is deterministic, put a script in the skill and tell the agent to run it, rather than letting the model regenerate the logic each time. The model handles judgement; code handles the parts that must be the same every time.

Treat skills as code. A skill can contain scripts that run with the agent's permissions, so a skill from the internet deserves the same scrutiny as a dependency. Keep company skills in version control, review changes, publish them through an internal registry and only allow approved sources. See running an enterprise MCP sub-registry for the same pattern applied to tools.

Tools: what the agent can actually do

Tools are how agents act: query a database, open a ticket, send a message, deploy a change. The Model Context Protocol has become the common way to expose them, and its 2026-07-28 specification made the protocol core stateless and added a formal extensions framework, which makes MCP servers easier to run behind ordinary load balancers3. See the MCP stateless migration playbook.

Design tools for agents, not for humans. Fewer, task-shaped tools ("create refund up to a limit") are safer and easier for a model to use than thin wrappers around every API endpoint. Mark which tools only read and which change things, and require approval for the ones that are hard to undo. The MCP server security checklist covers the details.

SkillToolWorkflow
What it isInstructions and scriptsA callable capabilityA fixed sequence of steps
Best forHow to do a task wellActing on a systemSteps that must always happen in order
Who decides the next stepThe agent, guidedThe agentThe code
Main riskMalicious or stale contentToo much permissionRigid when reality differs

Execution: sandboxes and workflows

Agents that write and run code need somewhere disposable to do it. The Kubernetes Agent Sandbox project, under SIG Apps, adds a Sandbox resource for isolated, stateful, single-instance workloads, with support for runtimes such as gVisor and Kata Containers, scale to zero when idle and warm pools to avoid cold starts5. That fills a real gap: an agent's workspace looks nothing like a stateless web service. See scale to zero on Kubernetes for the cost side.

Isolation is necessary but not sufficient, as the CNCF has argued6. A perfectly isolated sandbox holding a broad API key can still do damage through that key. Pair sandboxes with limited outbound network access, short-lived credentials scoped to the task, and monitoring of what leaves the sandbox; see agent sandboxing lessons and prompt injection defence.

Long-running work also needs a workflow layer: durable queues, retries, timeouts and human approval steps that survive restarts. Let the workflow own the order of steps that must always happen, such as "approve before payment", and let the agent work inside each step.

Control: identity, policy and a stop button

Every action an agent takes should answer two questions: which agent did it, and on whose authority. The MCP Enterprise-Managed Authorization extension, now stable, lets organisations grant MCP server access centrally through their identity provider, scoped to users' groups and roles, instead of each user authorising each server4.

Diagram comparing standard MCP authorisation, where the user authenticates to each server separately, with Enterprise-Managed Authorization, where one identity provider login connects all approved servers
Central authorisation through the identity provider: the basis for knowing whose authority an agent acts on. Source: Model Context Protocol Blog, Paul Carleton · CC BY 4.0

On top of identity, define policy per agent: which tools, which data, what spending or volume limits. And keep a stop button: a way to pause one agent, or revoke its credentials, in seconds. See the 4 November tech news on agent kill switches.

Evidence: telemetry, evaluations and cost

OpenTelemetry's generative AI semantic conventions define spans for agent invocations and tool executions alongside model calls, so a single trace can show what the agent was asked, which tools it called and what each cost in time and tokens7. Use them from the start; retrofitting telemetry onto agents in production is painful. Then run evaluations on real tasks whenever a model, skill or tool changes; see evaluating AI agents.

What to build, in order

  1. IdentityEach agent and action traceable to an agent and a person
  2. TelemetryEvery model and tool call recorded with cost
  3. ToolsA few task-shaped MCP tools, read-only first
  4. SkillsCompany procedures as reviewed, versioned skills
  5. SandboxesIsolated execution with scoped credentials
  6. WorkflowsDurable steps and approvals for high-risk actions
Control and visibility first; capability grows as the evidence allows.

Agents get more useful as you give them more skills and tools. They get safe enough to keep only when every action has an identity, a limit and a record.

CTO take

The interesting work in agentic AI has moved from the model to the infrastructure around it. Skills turn tacit company knowledge into something an agent can use and a reviewer can read. MCP makes tools portable. Sandboxes and workflows make execution safe and durable. Identity and telemetry make the whole thing governable. None of these needs a large platform team to start: a registry of approved skills and tools, agent identities in your existing identity provider and OpenTelemetry on every call will take most teams a long way. For how far to let agents run unattended, see dark factories and automating work, and for a worked example, the enterprise MCP agent platform case study.

How I can help

I design agent platforms: skills and tool registries, sandboxed execution, identity and policy, and the telemetry that shows what agents actually do. I am based in India, the United States and the UAE, working globally. See AI architecture, where I work, or analyse your challenge and bring the result to a call.

References
  1. 1
  2. 2
    Agent Skills specificationAgent Skills · 2026
  3. 3
    The 2026-07-28 SpecificationModel Context Protocol Blog · 28 Jul 2026
  4. 4
    Enterprise-Managed Authorization: Zero-touch OAuth for MCPModel Context Protocol Blog · 18 Jun 2026
  5. 5
  6. 6
  7. 7
FAQ

Common questions

What is the difference between an agent skill and a tool?

A skill is packaged know-how: a folder with a SKILL.md file of instructions, plus optional scripts and reference files, that the agent loads only when relevant. A tool is a capability the agent can call, such as an API exposed through an MCP server. Skills tell the agent how to do a task; tools let it act.

Do AI agents need their own sandbox?

Any agent that writes or runs code, or handles untrusted content, should run in an isolated environment with limited network access and short-lived credentials. Kubernetes now has an Agent Sandbox project for this, but isolation alone does not replace scoped permissions and monitoring.

What should a company build first for agentic infrastructure?

Identity and telemetry. Give each agent and each action a traceable identity, and record every model call and tool call. Without those, you cannot safely grant more permissions, debug failures or show auditors what happened.

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