check_instagram_handle

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It describes the tool's behavior ('returns information about the account if it exists, or confirms availability if it doesn't'), which covers the basic operation. However, it lacks details on potential limitations such as rate limits, authentication needs, or error handling, which would be helpful for a tool interacting with an external service like Instagram.

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 appropriately sized and front-loaded, consisting of two clear sentences that directly state the tool's purpose and return behavior without any unnecessary words. Every sentence earns its place by providing essential information efficiently.

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 low complexity (one parameter, no output schema, no annotations), the description is reasonably complete. It explains what the tool does and what it returns, which is sufficient for basic understanding. However, without an output schema, it could benefit from more detail on the return format (e.g., what 'information about the account' includes), but this is a minor gap given the simplicity.

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 has 100% description coverage, with the 'username' parameter well-documented in the schema. The description does not add any additional meaning or context beyond what the schema provides (e.g., it doesn't explain format constraints or examples), so it meets the baseline score of 3 for high schema coverage without extra value.

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's purpose with a specific verb ('Check') and resource ('Instagram username'), specifying what it does ('check if... available or already taken') and what it returns ('information about the account if it exists, or confirms availability if it doesn't'). It distinguishes from siblings by focusing on Instagram specifically, unlike other platform-specific tools like check_tiktok_handle or check_x_handle.

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 implies when to use this tool by specifying it checks Instagram usernames, suggesting it should be used for Instagram-related queries. However, it does not explicitly state when not to use it or name alternatives (e.g., using check_all_platforms for broader checks or other siblings for different platforms), leaving some guidance implicit rather than explicit.

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