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

The annotation readOnlyHint already signals safety. The description adds useful context about the returned signal (ranked by momentum) and its unique coverage of Western-feed blind spots. No hidden behaviors are disclosed, but the output schema covers return format, so this is sufficient.

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?

Two concise sentences: the first defines the tool's purpose and scope, the second gives actionable alternative guidance. No filler or redundancy.

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?

For a single-parameter read-only tool with output schema, the description covers purpose, scope, ordering, and when to use the alternative. It is fully sufficient for correct invocation without further external context.

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 input schema fully documents the 'limit' parameter with default and cap (100% coverage). The description does not add extra parameter semantics, but per the rubric, baseline 3 is appropriate when schema covers all parameters.

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 identifies the tool as a shortcut for 'get_region_signal' with region 'china', specifying exact geographic scope and example model providers (Qwen, DeepSeek, Zhipu, Moonshot, ModelScope). It also mentions the ranking by momentum, which distinguishes it from broader sibling tools.

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?

Explicit guidance is provided: 'Prefer get_region_signal if you may query more than one region.' This gives a clear condition for when to choose an alternative, making the usage context unambiguous.

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