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

Annotations already cover readOnly/idempotent/destructive, but the description adds real context: it requires login, returns null sentinels (round=null for no visible published round, group=null for no personal group), excludes drafts/published groupings, and can be re-read after check-in. These are behavioral traits beyond the structured annotations.

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?

Extremely compact, front-loaded with the login requirement, and every clause carries information (scope, null semantics, exclusions, re-read). Dense but not padded; slight density cost in parsing.

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 annotations covering the safety profile and no output schema, the description supplies the missing return-shape semantics (null sentinels) and scope boundaries. For a single-param read tool this is close to complete.

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?

Only one parameter (activityRef) with 100% schema description coverage ('活动 id 或 slug'), so the schema already carries the semantics. The description adds no additional format or syntax detail, so the baseline 3 applies.

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: read-only retrieval of the caller's published personal match group (with trimmed members/topics) for an activity they are eligible to join. It also scopes out what it does NOT read (drafts/published groupings), which helps separate it from related match tools, though no sibling is named directly.

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?

Implies usage through '【需要登录】' and '签到后可重读' (re-read after check-in), which hints at the post-check-in workflow, but there is no explicit when-to-use/when-not guidance and no named alternative among siblings like list_my_activity_matches or get_activity_match_time.

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