send_image

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

No annotations are provided, so the description carries the burden of behavioral disclosure. It discloses that a pre-uploaded image_key is required and that arbitrary image URLs are not accepted – a non-obvious behavioral constraint. It doesn't cover rate limits or error behavior, but for a simple send operation the key behavior is covered.

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 one short sentence plus a clearly marked '注意' note. It is front-loaded with the action and immediately adds the critical prerequisite without any filler. Every word earns its place.

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 one-parameter tool with no output schema and no nested objects, the description plus schema cover what the agent needs to invoke it correctly. The missing piece is what happens after sending (response/error), but that's minor given the tool's simplicity. It is nearly complete.

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 100%, so the parameter is already well-described with a format example ('形如 img_xxxxx'). The description adds meaning by explaining how to obtain the value (via the Feishu upload API), which goes beyond the schema's format-only hint. This justifies a score above the baseline of 3.

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?

States a clear action: '向飞书群发送图片' (send image to Feishu group). The resource type 'image' differentiates it from sibling tools send_text, send_markdown, send_card, send_post, and send_share_chat. The prerequisite about image_key adds further specificity.

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 includes a clear prerequisite: the image_key must come from the Feishu app upload API, which tells the agent what must be done before calling. It doesn't explicitly name alternatives or exclusions, but the image-specific function is obvious from the resource type. This is clear context without explicit when-not-to-use guidance.

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