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

With no annotations, the description carries the full behavioral burden. It discloses a key process ('re-verified daily against the official affiliate feed'), an edge-case return ('empty list when no offer is running'), and an integrity guarantee ('never stale or invented'). This is meaningful behavioral context beyond a simple one-liner.

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 sentences with no filler. The main subject is front-loaded, and each clause adds value: freshness, source, empty-list behavior, and reliability. It is compact without losing information.

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 no-parameter read-only tool with no output schema, the description is complete enough: it tells the agent what will be returned, when an empty list occurs, and how the data is maintained. Nothing essential is missing for correct 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?

The tool has zero parameters and the schema is empty, so parameter semantics are trivially 100% covered. The description adds nothing about parameters, but none are needed; the baseline 4 for a zero-parameter tool applies.

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 identifies the resource precisely as 'Current TicketNetwork promo/discount codes' and states the actual return behavior ('Returns an empty list'). This clearly distinguishes it from sibling tools that cover categories, events, mission, price index, and top cities, none of which deal with promo codes.

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 makes clear it is for retrieving current promo/discount codes, which gives an agent enough context to select it over unrelated siblings. It does not explicitly name alternatives or state when not to use it, but the scope is narrow and self-evident.

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