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

Annotations already declare readOnlyHint, idempotentHint, and non-destructive behavior, so the safety profile is covered. The description adds valuable context beyond annotations: the result is free, covers all agentfeed tools, and includes USDC prices plus descriptions. This gives the agent a clear expectation of what the tool returns without contradicting 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 with no filler. The usage directive is front-loaded, followed by a precise statement of the return content and cost. Every word earns its place.

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, read-only tool with a rich output schema and all safety annotations present, the description fully covers what the agent needs. It specifies when to call it, what it returns, and that it is free. Nothing essential is missing.

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 the schema is trivially complete. Per the baseline for no-parameter tools, a score of 4 is appropriate; the description correctly omits parameter details because none exist.

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 states a specific verb and resource: 'Returns every agentfeed tool with its USDC price and description.' It clearly identifies this as a meta-tool for retrieving tool pricing rather than a market data tool, distinguishing it from the many get_* siblings. The phrase 'before calling anything' further reinforces its unique role.

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 description gives explicit timing guidance: 'Use when an agent needs the price list before calling anything.' This tells the agent exactly when to invoke this tool and establishes it as a prerequisite for cost-aware tool selection. No alternatives are relevant since this is the only pricing-list tool among siblings.

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