count_materials

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

The annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint=false, so the safety profile is fully covered. The description adds minimal behavioral detail beyond stating that it retrieves counts, which is appropriate for a simple read operation but does not add extra context such as scoping or counting semantics.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single, concise sentence that states the core function without any redundant information. It is appropriately sized given the tool's zero parameters and simple read-only behavior.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

The tool is simple: no parameters, read-only annotations, and an output schema exists. The description sufficiently indicates what the tool returns (counts of permanent materials by type) without needing to enumerate return fields, since the output schema handles that.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The tool has zero parameters, so schema coverage is effectively 100% and description cannot add parameter-level meaning. The baseline of 4 applies because there are no parameter semantics to clarify.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states a specific verb ('获取'/get) and resource ('各类型永久素材数量'/counts of permanent materials by type). It also distinguishes itself from sibling tools like list_materials by focusing on aggregate counts rather than material details.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Usage context is implied through the purpose: use this tool when you need counts of permanent materials by type, not the material list themselves. However, it does not explicitly mention when to prefer this over list_materials or provide alternative routing guidance.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.