preview_feed

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

No annotations are present, so the description carries the burden. It usefully discloses that no subscription is created and that RSSHub URLs are normalized to rsshub://, which is behaviorally relevant. However, it does not mention whether network fetches occur, what the response contains, or whether any other side effects exist.

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 sentences, front-loads the core purpose, and adds a helpful RSSHub documentation pointer. There is no filler, and each sentence contributes useful information for selecting or invoking the tool.

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?

Given that there is no output schema and no annotations, the description should clarify what a preview returns—such as feed content, fetchability status, or errors—so the agent can use the result. It also leaves the limit parameter unexplained. The core purpose is clear, but important invocation details are 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 description coverage is 0%, so the description must compensate. It covers feedUrls by saying 'one or more feed URLs' and adds meaningful normalization semantics for RSSHub URLs. However, the limit parameter is never mentioned, leaving its meaning and impact undocumented for the agent.

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 states a specific action: preview one or more feed URLs without subscribing, in order to verify fetchability and content. This clearly distinguishes it from subscription tools like upsert_subscriptions and fetch_news, making its purpose unambiguous.

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?

The description gives clear context: use this before subscribing to verify a feed. It explicitly says 'without subscribing' and offers a concrete use case. It stops short of naming alternative tools for the actual subscription step, but the intended usage boundary is still clear.

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