AI Agent
自律型AIエージェント
An AI agent is an AI system that can reason toward a goal, use tools or external context, and carry out multi-step work. The more autonomy it has, the more permissions, auditability, and human checkpoints matter.
What it means
An AI agent is a system that interprets a goal, plans or selects steps, uses tools and data sources, and checks or updates its work across a task. Compared with a single chat response, an agent may combine search, file operations, API calls, planning, validation, and revision. Production agents need explicit boundaries for allowed tools, accessible data, human approvals, audit logs, and stop conditions. Without those boundaries, an agent can make mistakes faster and with broader operational impact.
How to calculate it
Evaluate AI agents by task success, safe execution, and human intervention load. Task completion rate | Successful tasks / attempted tasks | Measures practical usefulness Intervention rate | Human stops / executions | Shows whether autonomy is calibrated Safe execution rate | Policy-compliant executions / executions | Measures permission and audit health
| Lens | Formula / treatment | When to use it |
|---|---|---|
| Task completion rate | Successful tasks / attempted tasks | Measures practical usefulness |
| Intervention rate | Human stops / executions | Shows whether autonomy is calibrated |
| Safe execution rate | Policy-compliant executions / executions | Measures permission and audit health |
What counts / what does not
AI agents overlap with chatbots, workflow automation, and RPA, but differ by tool access and decision scope. Include | Planning, search, tool calls, file operations, API calls, validation, revision | Handles multi-step work Exclude | Unlimited autonomy, unapproved high-impact actions, ownerless decisions | Requires governance Make explicit | Tool set, data scope, approval gates, logs, stop conditions | Required for production use
| Item | Treatment | Why it matters |
|---|---|---|
| Include | Planning, search, tool calls, file operations, API calls, validation, revision | Handles multi-step work |
| Exclude | Unlimited autonomy, unapproved high-impact actions, ownerless decisions | Requires governance |
| Make explicit | Tool set, data scope, approval gates, logs, stop conditions | Required for production use |
What moves the number
Agent performance depends on tool design, permissions, evaluation, and failure boundaries as much as model capability. Tools | Narrow, well-described tools limit damage when something fails Permissions | Separate read, draft, execute, and external-send rights Evaluation | Long tasks need both intermediate and final checks Human review | Approval gates make autonomy safer to expand
| Driver | Metric impact |
|---|---|
| Tools | Narrow, well-described tools limit damage when something fails |
| Permissions | Separate read, draft, execute, and external-send rights |
| Evaluation | Long tasks need both intermediate and final checks |
| Human review | Approval gates make autonomy safer to expand |
When it helps
Teams can decide whether chat assistance is enough or whether tool-executing agents are justified. Classifying actions by approval requirement balances speed and safety. MCP or API integrations can be designed around tool descriptions, input schemas, permissions, and logs.
- Teams can decide whether chat assistance is enough or whether tool-executing agents are justified.
- Classifying actions by approval requirement balances speed and safety.
- MCP or API integrations can be designed around tool descriptions, input schemas, permissions, and logs.
How to use it
- An AI agent is a system for doing work, not just producing an answer.
- More tool access requires stronger logs, approvals, and rollback paths.
- Start with low-risk read or draft workflows before allowing high-impact execution.
- Measure intervention, misoperation, permission, and user burden alongside success rate.
- Standard connectors such as MCP are useful, but tool exposure must be intentionally scoped.
Decision cautions
Agent usefulness and agent risk scale together. External sending, deletion, purchases, contracts, and permission changes should require human approval. Ambiguous tool descriptions can cause tools to be invoked for the wrong purpose. Without execution logs and replay information, incidents cannot be investigated well.
- External sending, deletion, purchases, contracts, and permission changes should require human approval.
- Ambiguous tool descriptions can cause tools to be invoked for the wrong purpose.
- Without execution logs and replay information, incidents cannot be investigated well.
Read with
AI agents should be read together with MCP, tool use, evaluation, and prompt injection. Model Context Protocol | Standard for connecting tools and context | Often used in agent integrations Tool Use | Ability to call external systems | Defines execution scope Prompt Injection | Untrusted input can redirect actions | Especially important for agents
| Metric | Role | Why read together |
|---|---|---|
| Model Context Protocol | Standard for connecting tools and context | Often used in agent integrations |
| Tool Use | Ability to call external systems | Defines execution scope |
| Prompt Injection | Untrusted input can redirect actions | Especially important for agents |
Example
An engineering team uses an AI agent for first-pass incident triage. The initial tool set allows log reading, related PR search, and known-incident search, but it cannot change production settings or restart services. The agent writes a triage memo with evidence links and unresolved questions. A human approves the next step before any runbook action is taken. The workflow reduces triage time, but one incident shows that an old runbook was cited, so the team adds source freshness checks to the agent's retrieval layer.
Compare with
AI Agent | Carries out multi-step work toward a goal | Needs tools and evaluation Chatbot | Responds in conversation | Usually limited execution authority RPA | Automates fixed steps | Less flexible reasoning
| Metric | Difference | Why read together |
|---|---|---|
| AI Agent | Carries out multi-step work toward a goal | Needs tools and evaluation |
| Chatbot | Responds in conversation | Usually limited execution authority |
| RPA | Automates fixed steps | Less flexible reasoning |
Common mistakes
- Agents do not need to be fully autonomous. Human checkpoints are often the safer design.
- A better model alone does not remove operational risk. Tool and permission design matter.
- Long tasks do not automatically improve efficiency. Without intermediate checks, rework can grow.
Frequently asked questions
How is an AI agent different from a chatbot?
A chatbot mainly answers. An AI agent can combine multi-step reasoning with tools, data, and execution workflows.
Should agents be fully autonomous?
Not for high-impact actions. Use approval gates, logs, and stop conditions.
What should be automated first?
Start with read, draft, summary, and research-support tasks that are easy to review and roll back.