fetch_message_links

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

The description discloses that a network opt-in is required, which is a meaningful behavioral trait beyond the basic purpose. However, it is ambiguous whether the tool merely extracts URLs from the message or actually accesses them, and no side effects or auth requirements are mentioned. With no annotations, more behavioral context is needed.

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 a single, front-loaded sentence with no filler. It conveys the core purpose and a key constraint in eight words, making it highly concise and well-structured.

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?

Despite having an output schema, the tool has four parameters with no explanations, and the identification mechanism (via chat plus local_id/server_id_str) is undocumented. The network behavior is also ambiguous. This leaves significant gaps for a tool of this complexity.

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?

The schema provides no descriptions for any of the four parameters (chat, local_id, server_id_str, max_chars_per_link), and the description does not compensate. There is zero schema coverage, so the agent cannot determine how to specify the target message or the meaning of max_chars_per_link.

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 tool fetches public HTTPS links from a single message, using the specific verb 'fetch' and resource 'links'. This distinguishes it from sibling tools like message_media or extract_message_files.

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 no guidance on when to use this tool versus alternatives. It only mentions an 'explicit NETWORK opt-in required' constraint, which is a precondition rather than usage context. No exclusions or alternative tool names are provided.

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