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

Annotations already declare readOnly/idempotent/non-destructive/openWorld, so the safety profile is covered. The description adds non-obvious behavior: the following feed requires login and is typically empty, which an agent needs before choosing a feed. It does not describe pagination/return shape, so not a 5.

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?

Front-loaded with the core purpose and highly compact, with the auth caveat and sibling routing kept tight. The 【组合链】 arrow notation is slightly cryptic but does not pad the text.

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 7-parameter read tool with no output schema, the description covers the key decisions (which feed, auth requirement, sibling alternatives, downstream chains) and annotations cover safety. Return format is left to inference but is not essential for correct invocation.

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 100%, so both enum params and the attachType+attachId pairing are already documented in the schema. The description restates the recommend default and the attachType+attachId pairing rather than adding new syntax or constraints, 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 official news/activity/policy feed) and explicitly distinguishes the resource from the sibling moments feeds by naming list_moments_feed/search_moments and publish_moment. An agent can tell this is the official-content feed, not the user-moments feed, without opening any 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?

Gives explicit when-to-use context: recommend is the default feed, following requires login and is usually empty. It also routes user-moment needs to list_moments_feed/search_moments and publishing to publish_moment, and outlines downstream chains (get_post → get_activity/get_product, signup → get_signup_activity).

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