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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, covering safety. The description adds value by clarifying the lane scope and indicating that the output is a list of ids for subsequent use. It does not detail error cases or ordering, but for a simple read-only list this is adequate.

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 tightly written sentences, front-loaded with the core purpose. No redundant phrases; every word contributes. The example id and pointer to create_instant_shift are placed at the end, but the message is immediately clear.

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, no-output-schema tool, this description is fully sufficient. It states what is listed, what is returned, and how the output should be used. Nothing an agent needs to call it correctly 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?

With zero parameters and 100% schema coverage, the description needs no parameter explanation. The baseline for 0 params is 4, and the description still enriches by explaining the returned id format ('usdt-tron') and its purpose, which is useful context not in the schema.

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 clearly states the tool lists assets reachable via the INSTANT lane, specifies the corridors (Tron/USDT-TRC20, BTC, stablecoin), and explicitly mentions it returns ids for use with create_instant_shift. This verb+resource+scope is specific and distinguishes it from siblings like list_onramps or build_swap_transaction.

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 advises that returned ids are to be used with create_instant_shift, giving clear usage context. It does not explicitly discuss when not to use it or compare with other listing tools, but the purpose is unambiguous enough to guide selection. A brief exclusion note could push this to 5.

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