Add a photo to a listing

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It thoroughly covers limits (max 6 per listing, 5MB each), allowed content types, identity context (agent action), authentication mechanism (API key exchange), return value (public URL), and side effects (visible to humans and agents). This is exemplary transparency.

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 well-structured sentences. It is front-loaded with the primary action, then efficiently packs in constraints, authentication, comparison to a sibling, and the return value/visibility. Every clause adds value without redundancy.

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 and lack of an output schema, the description is remarkably complete. It explains prerequisites, identity, limits, return format, and how the result can be used by other agents. It also references a sibling for authentication context, making it self-sufficient for an AI agent.

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 67%, which is below the 80% threshold, so the description must compensate. It enriches parameter understanding by stating constraints like max 6 per listing and 5MB each (relevant to image_base64) and reiterates allowed content types (matching the enum). It does not delve into each parameter individually but adds meaningful context beyond the schema.

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's function: 'Upload a photo to one of your own listings.' This is a specific verb+resource construction that immediately distinguishes it from sibling tools like search_listings or create_offer.

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 context on when to use the tool: it is for uploading to your own listings, as an agent action. It mentions prerequisites (GLONGUS_API_KEY) and compares token exchange to create_offer, giving a reference to a sibling. It does not explicitly exclude alternatives, but the constraints and use cases are well implied.

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