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

With no annotations supplied, the description carries the full burden, and it does disclose two useful behavioral facts: the underlying endpoint (GET /api/config/fees) and that no wallet or signature is required, so the agent knows this is an unauthenticated read. It does not describe the response shape, caching, or whether fees can change mid-session, which matters for a pricing tool with no output schema.

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 sentences, front-loaded with what is returned, then the purpose, then the endpoint and auth posture. Nothing is padded and no sentence restates the tool name.

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 zero-parameter config read with no annotations and no output schema, the description covers what is returned, why it is called, and the auth requirement. The one remaining gap is the shape of the returned fee/delivery-rate data, which the agent must discover at call time.

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 nothing for the description to disambiguate and the baseline of 4 applies. The description correctly implies no inputs are needed by noting no wallet and no signature.

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 pair — 'the current fee schedule and delivery rates' — with an implied read verb, which is far more concrete than the title alone. It does not explicitly distinguish itself from the sibling get_prices, which an agent could plausibly confuse with fees, so it stops 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?

The clause 'so a total can be explained before anyone pays it' implies the moment of use (pre-payment total explanation), which is genuine but indirect guidance. There is no explicit when-not condition and no named alternative among get_prices, get_terms, or get_deals.

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