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

Annotations already declare readOnlyHint=true and destructiveHint=false, so safety is covered. The description adds genuine extra context: the gateway-level configuration prerequisite and the fact that no arguments are needed because the contract address is resolved externally. It does not contradict the annotations.

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?

Two sentences, front-loaded with the return payload, followed by the prerequisite. No filler and nothing that could be trimmed without losing 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?

With no output schema, the description carries the burden of describing return values and does so explicitly. It also states the configuration prerequisite. Only the absence of guidance on when to prefer a more targeted sibling keeps it short of a 5.

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, which is the baseline-4 case. The description correctly signals that no input is required and instead names the environment variable that supplies the target contract, which is useful even though it is not a schema field.

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 (PCCProtocol root contract state) and enumerates exactly what fields are returned: fee rate, total fees collected, escrow count, registry addresses. It is distinguishable from narrower siblings like protocol_fee or protocol_token_fees, though it never names an alternative it is not, which keeps it from 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?

Usage is only implied: an agent can infer this is a read-only state inspection, and the description adds a precondition (PCC_PROTOCOL_ADDRESS must be configured). There is no explicit when-to-call-this-vs-siblings guidance, so it sits at the minimum-viable level.

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