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

Annotations declare readOnly=false, openWorld=true, destructive=false, but the description adds the genuinely useful context the annotations lack: state prerequisites, ownership requirement, and the external/public effect of publishing to a buyer-facing marketplace. It stops short of explaining failure modes (e.g. what happens if status isn't READY) or whether listing is reversible.

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?

Three short sentences, front-loaded with the action and resource, followed by prerequisites and the return value. Every sentence carries information; nothing is redundant.

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?

Covers the action, prerequisites, ownership requirement, and the resulting listing URL, and an output schema exists so return details need not be expanded. It leaves out what an agent should do if preconditions are not met, which is the remaining gap.

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 description coverage is 100%, so constraints on title, description, tags, and category are already fully documented in the schema. The description adds no parameter-level meaning beyond what the schema provides, which is the baseline 3 case.

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 and resource ('List an already-uploaded file on the public Payaion marketplace'), names the platform, and clearly distinguishes itself from siblings like delist_from_marketplace and browse_marketplace. An agent can identify the operation without opening the schema.

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?

Provides concrete preconditions for use: upload must be in READY status and have a price set, and the caller must own the upload. It does not explicitly name the alternative (delist) or say when not to use this tool, which keeps it short of a 5.

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