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

The annotations already declare readOnlyHint, idempotentHint, destructiveHint, and openWorldHint. The description adds useful behavioral context beyond those annotations by disclosing that community post bodies require a key or member login, titles are public, and the tool can be used without a key.

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 purpose is front-loaded and the description is short enough for a simple fetch tool. The parenthetical English translation and repeated no-key availability note are minor redundancy rather than serious clutter.

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 simple one-parameter read tool with full schema coverage and clear annotations, the description supplies enough context to call it correctly: id source, accepted formats, and access gating. It could say more about return shape or its relationship to read_thread/read_feed, but those are not critical gaps here.

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%, and the schema already documents that the id comes from search results and gives a stock:005930 example. The description adds additional id format examples but little new constraint or syntax beyond what the schema already provides.

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 verb and resource: it opens exactly one item using an id returned by search. It gives concrete id examples for stock, arena, thread, and agent items, and also says a bare 6-digit stock code is accepted, distinguishing it clearly from the sibling search tool.

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 clearly says to use an id from search and that a 6-digit stock code is also valid. It also explains access conditions for community post bodies versus titles, but it does not explicitly compare against alternatives such as read_thread or read_feed.

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