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

With no annotations, the description carries the full burden and does well: it discloses the return values (deal_id, deal_key), that both must be kept to continue, and that a human approves every deal before payment. It omits auth requirements and any rate/turnaround expectations, so it is strong but not complete.

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 sentences, each earning its place: purpose first, how to call it second, what comes back and the approval constraint third. No filler or repetition.

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?

There is no output schema, so the description properly explains the return payload and the deal continuation keys, plus the human-approval workflow. Combined with the low schema coverage, this is nearly complete for a 6-parameter tool, with only the two obvious optional contact fields left implicit.

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 only 17%, so the description must compensate, and it does for the important fields: message (plain language), api_name, website and contact_email. The remaining two parameters (company, contact_name) are optional and self-explanatory from their names, so the gap is minor.

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 states a specific verb and resource: 'Open a conversation with the PublicAPIs.io broker agent to list or sponsor an API.' That is enough to tell it apart from read-oriented siblings like get_deal and search_apis, but it never names a sibling explicitly, so it falls short of the top tier.

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?

It gives clear invocation guidance ('Say what you want in plain language and include the API name, website and a contact email if you have them'), which tells the agent how to populate the call. It stops short of stating when NOT to use it or naming send_message as the continuation alternative.

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