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 genuinely new context beyond annotations: that the payload duplicates ucode_render_credits and that credit acquisition happens outside chat. It stops short of any return-format detail, but an output schema exists to cover that.

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 short sentences, both front-loaded with the routing preference first, no filler, and every clause carries actionable information for the agent.

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 parameterless read tool with an output schema and full annotation coverage, the description supplies exactly the missing pieces: that the data is redundant with a sibling and where credits are actually purchased. Nothing needed to call it correctly is absent.

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; the baseline for a parameterless tool is 4. The description's statement about shared data with ucode_render_credits is the only relevant semantic note.

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 gives a specific verb+resource ('List credit packages'), and the description cross-references the sibling ucode_render_credits, making clear this returns the same data. It differentiates from siblings by stating a preference, though the description itself never directly states 'lists the available credit packages' without relying on the title.

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?

Explicitly routes the agent away from this tool ('Prefer ucode_render_credits') and names the alternative, and adds the constraint that credits are added on the Ucode website dashboard, never in chat. This is explicit when/alternative guidance rather than inference.

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