etsy_message_seller

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

With no annotations, the description carries full responsibility for behavioral disclosure. It does disclose the login requirement, which is useful auth context, but it does not mention side effects, irreversibility, or expected outcomes after sending. For a mutation tool, this is a moderate gap.

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 short sentences, no filler, action first, and the auth caveat second. Every word earns its place, and the structure is easy to scan.

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?

The schema fully covers parameter semantics and the description states the login requirement, covering basic invocation needs. However, with no output schema and no annotation, the agent gets no information about what a successful send looks like or what errors to expect, which is a noticeable gap for a write tool.

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 the schema already documents all four parameters, including that listing_url is an alternative to shop_name. The tool description adds no parameter-level detail, so the baseline of 3 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 uses a specific verb ('Send'), a clear resource ('a message to a seller on Etsy'), and is distinct from every sibling tool, none of which handle messaging. It immediately tells an agent what the tool does and leaves no ambiguity about its domain.

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 phrase 'Requires being logged in' gives a concrete prerequisite and implies the agent should call etsy_login first if no session exists. It does not explicitly compare to alternatives or state when not to use the tool, but no sibling offers a competing messaging action.

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