fetch_wechat_article

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

With no annotations, the description carries the full behavioral burden and does so reasonably: it discloses the failure contract (ok=false with error and reason), the anti-bypass policy for verification pages, and that extraction_method is returned so the caller can judge fidelity. It omits rate limits, caching, or any auth requirements.

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?

Purpose is front-loaded, followed by the return payload, the two parameter semantics, then failure behavior in a single dense but waste-free paragraph. Slightly telegraphic in places, but every sentence carries information.

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?

Output schema exists, so enumerating return fields is bonus rather than necessity, and parameters and the failure path are both covered. The remaining gap is sibling disambiguation against parse_wechat_html, which the agent must resolve from the names alone.

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, and it does for the two non-obvious parameters: format is enumerated as 'markdown | text | both' (the schema has no enum) and max_chars is explained as a truncation limit with '0 = no limit'. Only url is left implicit, which is acceptable given the URL pattern is stated up front.

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 ('Fetch a public WeChat Official Account article') and even narrows the URL shape (mp.weixin.qq.com/s/...), so the agent knows exactly what is being fetched. It does not, however, differentiate itself from the sibling parse_wechat_html, leaving that disambiguation to the agent.

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 constraint 'never bypass verification pages' implies a when-not condition and warns the agent that some URLs will simply fail rather than be worked around. There is no explicit 'use X instead of parse_wechat_html' guidance, so the sibling relationship is only implied.

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