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

Annotations already declare a safe read (readOnlyHint=true, destructiveHint=false). The description adds value beyond them: ordering ("newest first"), cost ("Free"), and a visibility rule ("Everything except statements is visible to anyone who knows the address"). It does not describe the result shape or pagination depth, keeping it out of 5 territory.

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 short sentences, no padding; the primary action and the mutual-exclusivity constraint are front-loaded. Every clause carries information (scope, ordering, cost, visibility).

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 read-only list tool with no output schema, the description covers ordering, cost, input constraint and visibility. It leaves the shape of a returned deal and the pagination mechanism (the before/limit cycle) unstated, which is a modest gap given the missing 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 coverage is 75%, so most parameters are self-documented. The description adds a genuine constraint the schema does not express: seller and buyer are mutually exclusive and exactly one is required, even though both are optional strings in the schema. It clarifies pagination only implicitly via "newest first".

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 (list deals), the scope (of an address, as seller or as buyer) and the ordering (newest first). It is clearly distinguishable from get_deal by being plural/listing, though it never names the sibling it replaces. No sibling differentiation, so it stops short of a 5.

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 one concrete call constraint ("give exactly one of seller or buyer") and notes the call is free, which is useful. However, it offers no when-to-use/when-not guidance relative to get_deal or confirm_deal, so usage is only implied.

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