instagram_follow_user

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

Annotations declare readOnlyHint=false (write) and destructiveHint=false, which the description aligns with by stating 'Follow a user.' The description adds valuable context beyond annotations: the private account follow request behavior, the environment variable requirement, and the return fields (followed and user_id). It does not contradict any annotations and provides transparency about the outcome.

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 concise, using a short paragraph with sections for behavior, requirement, args, and returns. Each sentence adds information without fluff. It front-loads the core action and private-account nuance, then provides prerequisites and parameters. Slightly more structure could separate args into a list, but overall it is well-organized and efficient.

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 follow operation, the description covers everything an agent needs: how to specify the user (username or user_id), what happens with private accounts, the required environment variable, and the return values. An output schema exists but the description still states the return fields. With annotations covering idempotency and write nature, this is a complete definition for correct invocation.

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 input schema already describes both parameters ('Numeric user id. Use instead of username.' and 'Handle to follow, e.g. "nasa".'), giving 100% coverage. The description repeats this and adds the hint 'if you already have it' for user_id, which slightly clarifies when to use it. Since the schema largely covers semantics, the description adds marginal value, justifying a baseline of 3.

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 verb and resource: 'Follow a user as the logged-in account.' It also specifies the behavioral nuance for private accounts ('sends a follow request instead'), which distinguishes it from a generic follow action. The name itself also makes it unambiguous relative to siblings like instagram_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 provides a clear precondition ('Requires INSTAGRAM_ALLOW_WRITES=true') and a conditional behavior ('For private accounts this sends a follow request instead'). It also implies usage via the two parameter options (username or user_id). However, it does not explicitly compare with alternative tools, but there is no other follow tool among siblings, so minimal guidance is needed. Context is clear, but no exclusions are stated.

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