上传正文图片

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

With no annotations, the description carries the full load and does well: it discloses format and size constraints, the fact that the returned URL is directly embeddable, and the quota side effect. It omits permission/credential requirements and whether re-uploads create duplicates, but the operationally important traits are 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?

Two sentences, front-loaded with purpose and constraints, with the quota carve-out last as supporting detail. No wasted words.

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 upload tool with no output schema, the description still explains what comes back (a directly usable image URL) and what inputs are rejected on format or size. An agent has everything needed to call it and consume the result.

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% and the single parameter's schema description already enumerates local path, file://, http(s)://, and base64 data URI. The description adds only the format/size constraints, so schema does the heavy lifting — baseline 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 specific verb and resource (上传文章正文内使用的图片), its accepted formats and size cap (仅 jpg/png, ≤1MB), and the return value (可直接写入 <img src> 的微信图片 URL). The clause 不占用素材库数量限制 separates it from wechat_upload_image_material without the agent needing to open either schema.

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?

Makes the use case explicit — images embedded in article body — and implicitly rules out the material-library path by noting it does not consume material quota. It stops short of naming wechat_upload_image_material as the alternative, so the routing is inferred rather than stated.

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