Follow a user

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

Annotations already indicate this is a write operation (readOnlyHint=false) and idempotent (idempotentHint=true). The description adds critical behavioral context: it operates on a real account, rate-limited, and can trigger bans if abused. This goes beyond annotations.

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 concise sentences. The first states the core functionality, the second adds a vital warning. No wasted words.

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 action with one parameter and no output schema, the description covers purpose, parameter, and critical behavioral caveats. It is complete enough for an agent to understand when and how to invoke it, though it lacks prerequisite info (e.g., authentication).

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% with a clear description for the single 'handle' parameter ('The @username to follow'). The description reinforces this but adds no new semantics beyond the schema.

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 'Follow a Threads user by @handle', specifying the verb (follow) and resource (Threads user by handle). It is distinct from sibling tools like unfollow_user.

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 mentions the dangerous nature of follow/unfollow bursts and rate-limiting, implying cautious usage, but does not explicitly state when to use this tool versus alternatives like unfollow_user or when not to use it.

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