Arsenkin: limits

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

Annotations already declare readOnlyHint, idempotentHint, non-destructive, and openWorld, so the safety profile is covered. The description adds a non-obvious behavioral trait not in annotations — "Cost: free" — which matters when an agent is deciding whether to spend a call. It doesn't mention rate limits or auth needs, but those are minor here.

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?

Three short, front-loaded sentences: purpose, then usage timing, then cost. Nothing is redundant and each sentence carries distinct information.

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?

An output schema exists so return values need no explanation, annotations cover the safety/behavior profile, and the description adds usage timing and cost. For a zero-parameter read tool this is complete.

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 per the rubric the baseline is 4. The description adds no parameter detail, but none is needed given the empty schema with additionalProperties: false.

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 (total and spent Arsenkin limits), making it clear this is a quota/usage inspection tool. It doesn't explicitly contrast itself with sibling tools like arsenkin_status or arsenkin_estimate, but the resource name is distinctive enough to avoid confusion.

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?

"Use before prepare/submit to show what is left" gives concrete when-to-use guidance and names two sibling tools. It lacks explicit when-not conditions (e.g., that it's unnecessary after submission), but the context is clear enough to route the agent correctly.

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