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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds a little context by saying the data is the same as ucode_render_credits and mentioning the agent-facing x402 USDC on Base context, but it doesn't disclose additional behavioral traits such as auth requirements or response specifics.

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?

The description is short and each clause contributes either data equivalence, user routing, or agent context. The fragment 'Agents: x402 USDC on Base' is terse and slightly cryptic, but overall the structure is efficient and front-loaded.

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-parameter read-only listing tool with an output schema present, the description is largely complete. It identifies the sibling, clarifies the audience split, and notes the agent-specific payment context, leaving little that an agent needs to decide whether to invoke it.

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 has zero parameters, so there is no parameter semantics burden on the description; the input schema is already complete. A score of 4 is appropriate because nothing more is needed for parameter understanding.

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 title directly states 'List credit packages' and the description clarifies it exposes the same packs as ucode_render_credits, giving a clear resource and action. It distinguishes itself from the sibling tool by noting the data overlap and human preference for the sibling, though it relies somewhat on that reference rather than fully defining its own scope.

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 routing guidance: humans should prefer ucode_render_credits and the website dashboard, while the 'Agents:' note points agents toward this tool with x402 USDC on Base. It names the alternative and provides audience-based selection, but doesn't fully spell out when not to use this tool in all cases.

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