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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds value beyond them by disclosing what the result set excludes (navigation, encyclopedia, user and video aggregation panels), which shapes how an agent interprets the returned items. It does not cover rate limits, auth, or empty-result behavior.

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?

One front-loaded sentence carries the purpose and pagination support, and a second sentence carries the exclusion list. There is no filler, and the highest-value routing information comes first.

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?

An output schema exists, so return-value explanation is unnecessary, and the 100%-covered schema handles parameter detail. Purpose, scope exclusions, and pagination are all covered, so an agent has everything needed to call this correctly against its siblings.

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 the schema already explains both keyword (with examples and link/ID exclusions) and the page_token continuation protocol. The description only reiterates that pagination is supported, adding no format or syntax detail beyond the schema, which is the correct baseline of 3.

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 pairs a specific verb with a specific resource and scope ("按关键词或短语查找今日头条公开内容"), and immediately distinguishes itself from siblings by ruling out detail-by-link and user-search use cases. An agent can tell it apart from toutiao_get_post_detail_by_url and toutiao_search_users 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?

It gives explicit when-not guidance: not for reading a specified link's detail and not for finding users, which maps cleanly onto the toutiao_get_post_detail_by_url and toutiao_search_users siblings. What is missing is naming those alternatives directly, so the routing is strongly implied rather than stated.

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