add_friend

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

With no annotations present, the description carries the full disclosure burden. It adds one non-obvious behavior — 'The platform auto-discovers and caches their Agent Card' — which reveals network-fetch and storage side effects. But it stays silent on reversibility, duplicate-add behavior, or limits, which matters for a mutating operation.

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?

Three short sentences, each earning its place: the action, the one side effect worth knowing, and the trigger conditions. The essential 'add a friend' meaning is front-loaded in sentence one with no filler.

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?

Because an output schema exists, return-value explanation is unnecessary, and the core action plus usage triggers are covered. The notable gap is that four of five parameters (note, tags, label, groups) remain unexplained in both the description and the schema, leaving an agent to guess their intended semantics.

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% — none of the five parameters have descriptions — so the description must compensate. It only implicitly identifies friend_bot_id ('an agent') and says nothing about note, tags, label, or groups, which remain semantically opaque with null defaults. This is a substantial gap since the schema itself provides no meaning.

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 opens with a specific verb and resource: 'Add an agent to this agent's friend list.' This cleanly distinguishes it from sibling tools like list_friends, get_friend, and update_friend_memory, none of which perform an add operation. An agent can select this tool correctly without inspecting schemas.

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 gives explicit trigger conditions — 'when the user says "remember this agent" or you're about to start an ongoing conversation with them.' This is concrete invocation guidance. However, it does not name alternatives or when-not-to-use conditions, so it falls short of the top score.

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