Tool Scoping · Per-Agent Tool Binding (Least-Privilege Discipline)

Overlay posture: the base frameworks ([[crewai]], LangChain, LangGraph) all define tools and bind them, but treat scoping as a one-line "assign tools to the agent that needs them" footnote. This overlay makes the rubric first-class. Non-trivial claims cite inline against references/R1-source-evidence.md.

The lever the base skills under-surface: tool definition and tool binding are two separate decisions. You define a tool once (reusable class/function), but you bind it per-agent deliberately. The [[crewai]] SKILL states this in one clause — "tool 定义可复用；但每个 agent 只绑定其角色匹配的工具" [crewai-sop §DC-3] — and then moves on. Production failures (wrong-tool selection, an agent running a destructive op outside its role) come from skipping the binding decision and defaulting to "give everyone everything."

1. 何时激活 (When to Activate)