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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false, and openWorldHint, so safety is covered. The description adds genuinely new context: login is required, the call will not execute any check-in write, and legacy parameters are retained for compatibility but are no-ops.

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 login requirement and read-only nature are front-loaded in the first clause, followed by the App-only check-in flow and the legacy-parameter caveat. Each sentence carries information, though the density of constraints makes it slightly heavy for a status-read tool.

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 read-only tool with no output schema, the description covers the essentials an agent needs: authentication requirement, the fact that no write occurs, the App-only verification path, and the legacy-parameter caveat. Nothing critical for correct invocation is missing.

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 description coverage is low (25%): only 'consent' is documented in the schema. The description hints that some parameters are legacy compatibility shims that won't perform writes, which adds partial meaning, but it does not explain preview, previewHash, or the required activityId semantics.

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 states a specific read-only verb and resource ('只读本人活动签到状态和 App 续接入口') and immediately clarifies that it does NOT perform the actual check-in write. This resolves the ambiguity created by the name 'check_in_my_activity' and separates it from write-oriented siblings like check_in_attendees.

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 gives explicit when-not guidance: on-site check-in must be done by the user in the App via location or dynamic code, and Agent/web/mini-program do not check in on behalf; no auto signup or ticket purchase. It stops short of naming a specific sibling alternative tool to route to instead.

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