ebay_send_message

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

With no annotations, the description bears full responsibility for behavioral disclosure. It fails to mention important traits: that it can start new conversations or reply to existing ones, any prerequisites (e.g., authentication), rate limits, or that messages are sent immediately. The description is too brief to ensure the agent understands side effects or constraints.

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 is two sentences, no extraneous words, and front-loads the primary action. Every sentence adds value, achieving maximum efficiency.

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 6 parameters (some conditionally required), no output schema, and the need to distinguish between new and existing conversations, the description is insufficiently complete. It does not explain parameter interdependence or media attachment capabilities, leaving the agent with gaps despite good schema coverage.

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%, so baseline is 3. The description adds no extra parameter semantics beyond what the schema already provides. It does not clarify conditional parameter relationships (e.g., conversationId vs. otherPartyUsername) or usage patterns, so it does not enhance understanding.

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 action ('Send a direct message'), the recipient ('to a buyer'), and the context ('regarding a specific transaction or inquiry'). It enumerates specific use cases (orders, questions, issues, updates), making the purpose distinct from sibling communication tools like getting conversations or leaving feedback.

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 clear when-to-use guidance: 'communicate about orders, answer questions, resolve issues, or provide updates.' However, it does not explicitly state when not to use this tool or mention alternative tools (e.g., ebay_get_conversations for reading messages), leaving some ambiguity for the agent.

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