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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and closed-world, so the safety profile is covered. The description adds the 'Haven-only' scoping caveat, which is useful, but says nothing about return shape, units, or behavior when the key is absent.

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?

One short sentence with no padding; the alias relationship is front-loaded. It is arguably too terse for a tool definition, but nothing is wasted.

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 trivially simple, read-only alias with a fully documented one-parameter schema and clear annotations, the description is mostly sufficient. The remaining gap is that it never states what the alias actually returns or why an agent would pick it over my_credits.

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 description coverage is 100% for the single optional api_key, so the schema carries the burden. The description adds no extra meaning about the parameter (e.g., whether it is ignored when an Authorization header is present), which matches the baseline 3 for fully documented schemas.

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 names the resource it exposes (ANANSI credits) and identifies this entry as an alias of my_credits, so an agent can tell it apart from unrelated siblings like balance or ledger. However, it defines the tool by reference to another tool rather than stating the action directly ('retrieves your ANANSI credit balance').

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?

Naming my_credits as the canonical tool implies either may be called, and 'Haven-only' scopes applicability, but there is no explicit when-to-use-this-vs-my_credits guidance (e.g., 'prefer my_credits; use this only for legacy callers').

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