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

No annotations are provided, so the description carries the full burden. It implies a read-only balance lookup, but never states that explicitly, nor does it disclose auth requirements beyond the schema, pagination, or freshness of the balance.

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 concise sentence that front-loads the resource and enumerates the buckets. No waste, though it is quite terse.

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?

For a simple no-required-param read tool this is minimally viable, but with no output schema and no annotations the description should say more about what is returned or the read-only nature. Adequate, with clear gaps.

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?

Schema coverage is 100% and the single api_key param is fully described there, including the Bearer/HAVEN_API_KEY alternative. The description adds nothing about parameters, which is acceptable at full coverage.

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 resource (credit balance) and breaks it into meaningful buckets (purchased/earned/promo), which tells the agent exactly what this returns. It doesn't distinguish itself from siblings like my_credits, ledger, or my_rewards, which the agent must disambiguate from the name 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 when-to-use guidance and no mention of alternatives, despite several closely related siblings (my_credits, ledger, my_rewards). The agent gets no signal on how this differs from those.

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