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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description adds meaningful behavioral context beyond that: returns a 'last good read' (implying cached/resilient data), derives market stats from fills, and provides an operational gating rule. It stops short of describing staleness bounds or refresh behavior, but is strong overall.

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 dense but every clause carries useful information, and the critical gating instruction is front-loaded after the enumerations. A minor split into shorter sentences would improve readability, but there is no filler.

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 input parameters and no output schema, the description carries the burden of explaining the return shape, and it does so by enumerating the availability state, last read, open offer count, and four market stats. It is complete for an agent deciding both whether to call it and how to interpret the result.

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?

There are zero parameters, so the schema baseline is 4. The description adds no parameter semantics because none are needed, which is appropriate.

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 resource (swap status) and enumerates exactly what is returned: availability state, last good read, open offer count, and market stats. It distinguishes itself from sibling swap tools like get_swap_offer and list_swap_offers by framing itself as a precondition check.

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?

It explicitly says 'Check this before any swap' and gives a conditional exclusion: 'when available is false, don't call swap-take.' This is clear when-to-use and when-not guidance with a named follow-on action.

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