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

Annotations already declare readOnlyHint=true, openWorldHint=false, and destructiveHint=false, so the safety profile is covered. The description adds the useful 'RETURNS: 图注文本' statement, which matters because there is no output schema. However, it says nothing about legend length, language, whether it cites statistics from the chart, or any limits.

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?

A compact pipe-delimited format with the name and purpose first, then trigger, aliases, and return value. There is no filler text, though the ALIASES list is mostly redundant with the bilingual title.

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 small tool with two parameters and no output schema, this is close to complete: purpose, trigger, and a return-value hint are all present. What remains missing are the content expectations for the legend and the role of the optional context, so it falls short of fully sufficient.

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 parameters are already documented as 图的背景与数据 and 图类型. The description only echoes 'for a given chart type' and adds no format, length, or content guidance for either the required chart_type or the optional context. Baseline 3 applies.

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 names a specific verb and resource: writing a figure legend / 图注生成 for a given chart type. That resource is clearly distinct from the plotting or statistics siblings such as forest_plot or citation_format. It does not name a sibling to contrast with, but the purpose is unambiguous.

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 'USE WHEN: write a figure legend for a given chart type' clause gives a trigger condition, but it largely restates the purpose. It never says when not to use this tool, what the alternatives are, or whether 'context' or the chart data must be supplied first. It provides implied usage, not selection guidance.

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