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

Annotations already declare readOnly/idempotent/non-destructive/open-world, so the safety profile is covered. The description adds value beyond them: it requires login, exposes the meaning of specific status codes, and importantly warns that organizer_profile_required needs App SMS verification which MCP cannot write — a real limitation an agent must know.

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?

Tightly packed: login requirement and purpose are front-loaded, followed by criteria and then an arrow-mapped error-code→action table. Every clause carries information, though the telegraphic notation is dense and slightly cryptic without domain familiarity.

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?

With no output schema, the description still conveys the failure codes and required remediations, which is the bulk of what the response carries. It does not explicitly describe the success-case payload, a minor gap for a zero-parameter gate.

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?

The tool takes zero parameters, so there is nothing for the description to disambiguate. Baseline for a parameterless tool is 4; no misleading parameter claims are made.

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+resource (check eligibility to host an activity) and enumerates the exact criteria evaluated: host bio/intro ≥10 chars, published product, organizer onboarding with org/contact/phone/intro. An agent can distinguish this pre-flight gate from create_organizer_activity without opening 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?

Explicitly says to run this before hosting (办活动先查) and then routes each outcome to the correct next tool: profile_incomplete→onboarding, no_published_product→create_product, all clear→create_organizer_activity. When-to-use, when-not, and alternatives are all named.

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