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

Annotations only provide destructiveHint=false, so the description carries most behavioral context: it adds the login/organizer requirement, the 1-hour signed link for non-public activities, the file-only side effect, the no-send constraint, and activity-state prerequisites. This is substantial disclosure beyond the annotation.

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?

Dense but front-loaded: the login/organizer requirement, return link, format mapping, workflow, and constraints appear in a compact sequence. Every clause carries operational value, with no filler.

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?

Despite having no output schema, it explains the returned download link and expiry along with file-only behavior and prerequisites. It leaves minor ambiguity around the return shape for list scope and docxMerge.

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 baseline is 3; the description adds useful meaning by mapping formats to styles (docx for official letters, pdf for official/business, png for all styles) and explaining list/pick grouping. It does not cover docxMerge or enumerate the style values, so it remains incomplete.

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?

Uses a specific verb and resource: "把邀请函出成文件" (render the invitation letter as a file) and states that it returns a download link. It also distinguishes itself from get_activity_letter by positioning that tool as the preceding style/format lookup step.

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?

States clear prerequisites: logged-in organizer, activity published and not cancelled, and use get_activity_letter first for style and format. It also explains post-generation handling for PNG versus PDF/Word and explicitly excludes sending on the user's behalf, but it does not name the sibling tool to use for delivery.

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