设置短故事封面

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

With no annotations, the description carries the full burden and does disclose non-obvious internals: the upload goes through the edit-page entry and the page performs the cover/v0 signing itself, plus the two-stage upload-then-save semantics driven by confirm. It omits auth/login prerequisites and failure behavior, keeping it short of a 5.

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?

Purpose is front-loaded in the first clause, and the parenthetical plus one short sentence about confirm carry real information without padding. Nothing is wasted, though the parenthetical interrupts the main clause slightly.

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 4-parameter mutation with no annotations and no output schema, the description covers the upload/persist mechanism adequately but leaves the headless flag unexplained and says nothing about authentication, permissions, or what success/failure looks like.

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 coverage is 75%, so baseline is 3. The description repeats the confirm default that the schema already documents and adds nothing about headless, the one undocumented parameter, nor about cover_path format beyond "本地封面图片路径".

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 states a specific verb (upload a local cover image) applied to a specific resource (an existing short story), and the parenthetical explains the mechanism used (the edit page's file upload entry). This clearly separates it from siblings like create_short_story_tomato, delete_short_story_tomato, and publish_short_story_tomato.

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?

It implies the story must already exist ("为已有短故事"), which is a useful precondition, and notes the default confirm=false behavior. However, it never names an alternative (e.g. setting a cover at creation time via create_short_story_tomato) or states when this tool should not be used, so usage is only implied.

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