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

Annotations only supply idempotentHint=true and destructiveHint=false; the description goes well beyond them by disclosing that a partial list causes sortOrder collisions ('漏项会撞序号'), that non-member ids are silently ignored ('外场id静默忽略'), and that the caller must verify the returned complete list. These are exactly the silent-failure modes an agent needs to know before calling a mutating reorder.

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?

Every clause carries a distinct operational fact and the prerequisite is front-loaded, so there is no filler. The telegraphic semicolon-chained style is dense and slightly harder to parse than a two-sentence structure would be, which keeps it just short of top marks.

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 two-parameter, non-destructive reorder with no output schema, the definition covers the precondition, the exact shape of the input, the ordering convention, failure behavior, and the return-verification step. Nothing an agent needs in order to call it correctly 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 coverage is 50% — activityRef is documented, but the ids array is bare. The description compensates fully: ids must be the complete new order of all materials for the activity, index position maps to sortOrder starting at 0, and foreign ids are dropped rather than erroring. That is meaning the schema cannot convey on its own.

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 verb and resource (reorder this activity's material ids) and scopes it sharply: '只排序' (reorder only). It explicitly contrasts itself with two siblings — list_activity_materials as a prerequisite and update_activity_material as the tool for renaming/visibility — so an agent can pick it out of a very crowded tool list without opening a 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?

It gives an ordered precondition ('先list_activity_materials'), a required confirmation step ('并确认'), and explicit exclusions ('只排序，改名/可见性update_activity_material'). The alternative tool is named together with the condition that selects it, leaving nothing to inference.

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