Get Me

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

The description adds behavioral context beyond the annotations: it reveals the tool relies on the imported browser-cookie session (c_user / xs) and implies it can validate session validity. With readOnlyHint=true, the read-only nature is already known, but the session dependency and its purpose are valuable additions. The description does not contradict 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?

The description is extremely concise: three short sentences that cover purpose, usage context, and return value. It is front-loaded with the primary action, and every sentence earns its place. No unnecessary fluff or repetition.

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 (no parameters, read-only, output schema present), the description is complete. It explains what the tool does, when to use it, and what it returns. The output schema exists, so return value details are redundant but still summarized. The description covers all necessary aspects for an agent to select and invoke this tool correctly.

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 tool has zero parameters, and schema description coverage is 100% (vacuously). Per the guidelines, a baseline of 4 is appropriate since no parameter documentation is needed. The description still adds useful context by explaining the underlying data source (cookies), which indirectly clarifies why no parameters are required.

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 'Get the identity of the authenticated Facebook user' with a specific verb and resource. It distinguishes itself from sibling tools like get_account_status (which likely checks account status) and get_active_account_info (which might return active account details) by focusing on identity fields (id, name, username). The purpose is unambiguous and unique.

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 usage context: 'Useful to confirm whose session is configured and whether it is still valid.' This tells the agent when to use the tool. It does not explicitly mention alternative tools or exclusions, but the context is sufficient for a focused identity tool. A slight improvement would be naming alternatives like get_account_status, but it's not necessary.

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