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

The annotations already mark the tool as readOnlyHint=true. The description adds useful behavior beyond the annotations: it accepts Chinese city names such as “东京” and “纽约” and defaults to Beijing time. It does not describe error handling or invalid-timezone behavior, but that is a minor gap for a simple read-only lookup.

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 three tightly written sentences with zero waste. It is front-loaded with the core purpose and then gives usage triggers and a typical input example.

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 simple read-only tool with two optional parameters and no output schema, the description provides sufficient context: purpose, usage triggers, default timezone, Chinese city-name support, and an example. It could mention the return format or invalid-timezone behavior, but those are small omissions.

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?

Schema description coverage is 100%, so both the timezone and format parameters are already documented in the schema. The description adds a typical input example and repeats the Chinese-city-name acceptance, but it does not provide meaning substantially beyond what the schema already states.

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 gives a specific verb and resource: '获取指定时区的当前日期时间'. It clearly covers retrieving the current date and time for a timezone. However, it does not distinguish this tool from the sibling world_time, which likely has overlapping scope, so it does not earn a 5.

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?

The description explicitly lists when to use the tool: '当任务涉及

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