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

With no annotations, the description carries the full behavioral burden. It usefully discloses that the call returns the broker's answer and the deal status (valuable given no output schema), but says nothing about permissions, synchronous vs asynchronous delivery, rate limits, or what happens on a closed deal.

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 tight sentences with the action front-loaded and the return behavior second; nothing is wasted. It is arguably too terse given the unexplained parameters, but structurally it is clean.

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?

For a 3-required-parameter mutating tool with no annotations, no output schema, and 0% schema description coverage, the description covers only purpose and a hint at the return value. It leaves parameter meaning and preconditions undocumented, which is not enough for reliable invocation.

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 0% for all three required parameters. "Reply to the broker" loosely implies the message parameter, but deal_id and especially deal_key (likely a credential) are entirely unexplained in both schema and description, so the description fails to compensate for the coverage gap.

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?

States a specific verb and resource (reply to the broker) plus the scope constraint (an open deal), which separates it from read-oriented siblings like get_deal and start_deal. It does not explicitly name or contrast any sibling, but the purpose is unambiguous.

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?

"In an open deal" implies the precondition that the deal must already exist and be open, which is useful routing context versus start_deal. However, there is no explicit when-to-use/when-not guidance and no mention of what to do if the deal is not open or already closed.

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