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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the agent knows this is a safe, non-mutating read against a specific external account. The description adds no further behavioral context such as whether the account must be linked first, error behavior when unlinked, or units/currency of the credits.

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 sentence, front-loaded with the resource and framed around the value returned, with no wasted words. The interrogative phrasing is slightly indirect for a tool description but remains immediately parseable.

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 no parameters, no output schema, and annotations covering the safety profile, the description carries only the burden of stating what comes back, which it does ('how many credits are left'). Minor gaps remain around account-linkage prerequisites and the exact return form, but nothing essential to correct invocation is missing.

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 there is no parameter semantics to document; the baseline for a no-parameter tool is 4. Nothing in the description contradicts or muddies the empty schema.

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 states a specific resource (Kavel credit balance) and what is returned (credits left on the linked account), so an agent knows exactly what this tool retrieves. It does not, however, differentiate itself from siblings like check_kavel_generation or find_kavel_tool, leaving the agent to infer the boundary from names alone.

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?

There is no statement of when to use this tool versus the siblings (check_kavel_generation, find_kavel_tool, generate_kavel_image), nor any prerequisite or context for invoking it. The purpose is simple enough that implied usage is obvious, but no explicit guidance is offered.

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