add_friend

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

With no annotations, the description carries the burden of behavioral disclosure. It reveals a key behavioral trait: 'One add per call.' It also implies mutation (adding a friend). It does not discuss permissions or rate limits, but for a simple operation this is adequate.

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?

Two short sentences, each essential. No redundancy, directly conveys purpose and a key constraint. Front-loaded with the verb and resource.

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 the tool's simplicity (1 parameter, no output schema), the description covers all necessary aspects: what it does, how to use it, and a limitation. No 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?

Schema coverage is 100%, so the parameter is already documented. The description adds value by providing usage context ('e.g. from get_group_members or find_contact') beyond the schema description, helping the agent understand valid inputs.

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 ('Adds'), the resource ('a person to your LINE friends'), and the method ('by their MID'). It provides examples of where to obtain the MID, making the purpose unmistakable. It distinguishes itself from sibling tools like block_contact or find_contact.

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 context on how to obtain the MID from other tools (get_group_members, find_contact), implying usage context. However, it does not explicitly state when not to use it or compare with alternatives like accept_invitation.

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