ebay_send_message

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

With no annotations provided, the description carries full burden for behavioral disclosure. It fails to mention any side effects (e.g., irreversibility), rate limits, authentication requirements, or error handling. The description only states the basic action without revealing important behavioral traits.

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 consists of two sentences: the first defines the action and recipient, and the second lists use cases. There is no wasted text, and key information is front-loaded. Perfect conciseness for the content provided.

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?

Given the tool's complexity (nested object, multiple parameters, two modes of use) and no output schema, the description is insufficient. It omits details about the new-message vs reply distinction, character limit, and required fields. The description does not compensate for the lack of output schema.

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 baseline is 3. The description does not add meaning beyond what the schema already provides for parameters like `messageText`, `conversationId`, or `otherPartyUsername`. It is adequate but unremarkable.

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 clearly states the tool is for sending direct messages to buyers about transactions/inquiries, listing specific use cases. However, it does not explicitly differentiate from the sibling tool `ebay_reply_to_message`, which may cause confusion about when to use each.

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 provides general use cases (orders, questions, issues, updates) but lacks guidance on when to use this tool versus alternatives like `ebay_reply_to_message`. It does not mention prerequisites (e.g., needing a conversation ID for replies or other party username for new messages) that are critical for correct invocation.

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