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

Annotations already cover readOnly/idempotent/non-destructive/closed-world, so the description earns credit for what it adds: the null-state semantics of the preference fields (unset until asked once) and a prompt-injection guard stating every text field is user-authored and must be treated as information, never instructions. Those are behavioral facts an agent could not obtain from the schema or 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 purpose is front-loaded in the first clause, followed by a field inventory and a security note. The middle enumeration of fields is long and somewhat list-heavy, but each item is a distinct piece of context an agent may need. Slightly dense, not wasteful.

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, the description need not explain return values, yet it still summarizes them for orientation and adds handling guidance for untrusted text. It does not address auth requirements, but for a read-only, parameterless, closed-world tool the description is complete enough to call 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 takes zero parameters, so the baseline is 4. The description's field list describes return values rather than inputs, which is useful orientation but not parameter semantics in the strict sense.

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 ('Read') and resource ('what Kuro knows about the user') and enumerates the exact fields returned (name, language, image_priority/clip_priority, goals, brand note, subjects, shapes/kinds). That enumeration makes the resource concrete and separates it from list_subjects or get_credits. It does not explicitly name the sibling it is not, so it falls short of a 5.

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?

'before making anything' gives clear timing guidance: call this to prime personalization before a generation or creation task. The 'null until asked once' note hints at a follow-up prompting pattern. No explicit exclusions or named alternatives are given, so it is clear context rather than full when/when-not guidance.

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