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

Annotations already declare readOnlyHint, idempotentHint, non-destructive, and closed-world, so the safety profile is fully covered. The description adds the returned fields (email, ID), which is modest extra context, but says nothing about auth requirements or behavior beyond what the annotations and output schema convey.

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?

A single short sentence with the resource, scope, and payload front-loaded. No filler, no redundancy; every word earns its place.

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?

With an output schema present, return values need not be re-explained, and annotations carry the safety profile, so the description is nearly sufficient for a zero-parameter read. The one real gap is the absence of any signal separating this from the similarly named get_profile sibling.

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 takes zero parameters, so parameter documentation is not needed and the baseline is 4. The description correctly implies no input is required by scoping the call to the signed-in user.

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?

States a specific verb (Get) and resource (signed-in user's Nestling profile), plus the returned fields (email, ID). The scope word 'signed-in' distinguishes it from a generic profile fetch, but it does not differentiate itself from the sibling get_profile, which an agent could easily confuse it with.

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?

Usage is only implied: 'signed-in user's ... profile' suggests it is for retrieving the current account rather than another entity. There is no explicit when-to-use, no when-not-to-use, and no mention of the competing get_profile sibling, so the agent must infer the routing.

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