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

Beyond the readOnly/idempotent annotations, the description discloses the legal-signature side effects of the companion submit step, the need to reuse this call's exact versionId because organizers may publish new versions, the null behavior, and the 30k-character body limit. No contradiction with annotations exists; this context materially shapes how an agent should act.

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 text is organized into three labeled sections with the trigger condition first, and every sentence carries operational value. Despite its length, it avoids filler and each caveat addresses a distinct failure mode.

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?

Even without an output schema, the description covers return semantics (null vs full text), the versionId field needed downstream, the url/body behavior, and error conditions like activity_agreement_version_changed. This is sufficient for an agent to invoke the tool correctly and safely in the signing flow.

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?

There is only one parameter and the input schema already provides 100% coverage by defining slug as '活动 slug', so the bar is lower. The description embeds slug in the chain and submit signature but does not add new format or validation details beyond the schema.

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 action ('取全文一字不改念给用户') and resource (a registration agreement for an activity), and distinguishes it from related tools by tying it to get_signup_activity's agreement.required flag and the submit_signup handoff. It also states the null convention for activities with no agreement, so an agent knows exactly what this tool returns and when it applies.

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 opens with an explicit 【何时用】 block: use when get_signup_activity has agreement.required=true and accepted=false, or after an activity_agreement_required submission error. It also gives a when-not-to-use rule (required=false means already signed/no need to read) and a full combination chain ending in submit_signup with the agreement payload.

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