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

Annotations already say readOnlyHint=true, and the description usefully adds that 'this tool never moves funds' and that signing/funding happens outside the tool. That clarifies the two-step flow and the boundary of tool responsibility, which is real value beyond the annotations. It stops short of describing the price ceiling semantics or what happens if the returned request expires.

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 compact sentences, front-loaded with the outputs returned and followed by the execution model. No filler and nothing redundant with the schema or annotations.

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 output schema, the description does tell the agent what comes back (URL, price ceiling, wallet steps) and who acts next (the wallet-enabled agent). The main gap is the absence of any routing signal versus the six per-asset sibling prepare tools, which matters given how similar they are.

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?

Schema coverage is 100% and the symbol enum is fully documented in the schema, including the TZ-SELECT meaning, so the description need not repeat it. Baseline 3 is appropriate since the description adds no extra meaning about the symbol parameter.

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?

States a specific verb (return) and concrete artifacts (paid resource URL, price ceiling, wallet steps) for one setup, which is far more informative than the title alone. However, it never explains how this generic tool differs from its near-identical siblings prepare_btc_4h_purchase, prepare_eth_4h_purchase, etc., leaving the agent to guess why it would pick this one over a per-asset variant.

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 second sentence implies the workflow ('the wallet-enabled agent signs and retries the returned HTTPS request'), which tells the agent this is a prepare-then-retry step rather than a completion. But there is no explicit when-to-use, when-not-to-use, or pointer to discover_4h_setups / the per-symbol siblings as alternatives.

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