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

The annotations already establish a readOnlyHint=true profile, and the description adds behavioral nuance: the tool only prepares calls, while the caller must encode, sign, and submit them. This does not contradict the annotations and helps the agent understand that invoking the tool does not execute the listing.

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 sentences convey the tool's target, its purpose, and the caller's follow-up step. There is no fluff, and the core purpose is 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 four-parameter prep tool with a complete schema and an output schema, the description is sufficiently complete. It even includes the critical nuance that the caller is responsible for encoding, signing, and submitting. It could be stronger by explicitly distinguishing among the several prepare listing siblings, but the marketplace and purpose are clear enough.

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 input schema provides 100% coverage of the four required parameters, including formats and meanings. The description adds no extra parameter-level detail, so the baseline of 3 is appropriate: the schema is doing the heavy lifting.

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 begins with a concrete verb and object, 'Prepare token approval and listing calls,' and specifies the exact scope, 'NFH-owned Sepolia marketplace.' This clearly distinguishes it from mainnet or general-purpose listing siblings without requiring the agent to inspect schemas.

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 clear context about which environment this tool targets: the internal Sepolia marketplace. It does not explicitly name alternatives such as prepare_mainnet_listing or prepare_listing, so it misses the explicit when-not-to-use guidance required for a 5.

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