briefing_set_sources

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

The description discloses that existing custom sources are preserved, which is a useful side-effect. However, it does not state whether existing category-based subscriptions are overwritten, which is a key behavioral trait for a 'set' operation. With no annotations, this gap matters.

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 description is two short sentences, front-loaded with the primary action and followed by a critical preservation note. No unnecessary wording.

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?

The description covers the trigger condition and preservation of custom sources, but lacks critical details such as whether previous category subscriptions are replaced, what the return value looks like, or error handling. Given no output schema, this is a notable gap.

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 100%, with both parameters clearly described. The description adds little beyond the schema, only reinforcing that category_ids are the categories to subscribe to. This meets the baseline but does not add extra value.

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 clearly states the action '按分类订阅新闻来源' (subscribe to news sources by category) and provides the specific trigger context ('after user confirms recommended sources'), which distinguishes it from sibling tools like briefing_add_sources or briefing_suggest_sources.

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 explicitly says to invoke this tool after user confirmation of recommended sources, tying it to the recommendation workflow. It does not mention when NOT to use it or explicitly name alternatives, but the usage context is well implied.

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