APX Agent Tools Field Should Only Be Set When Restricting Capabilities

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In the APX agent runtime, the 'tools' field in an agent definition carries significant weight: omitting it grants the agent APX's broad default toolset, while declaring a list enforces a strict allowlist. This design separates the portable Agent Project Context (APC) layer, which stores agent definitions in repository files, from the APX runtime layer, which resolves available tools on the current machine. Developers are advised to declare tools only when intentional restriction is the goal, such as creating a read-only reviewer agent limited to 'read_file' and 'glob'. Populating the tools field with every currently available tool creates unnecessary maintenance overhead without establishing a meaningful capability boundary. When auditing agent definition files, teams should retain a tools list only if it enforces a deliberate constraint, and remove it otherwise to let APX supply an appropriate runtime default.

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