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

With no annotations, the description carries the full burden. It usefully discloses the three returned metrics, but does not state whether this is a read-only aggregate, how 'this week' is defined (calendar week, rolling 7 days, timezone), or what data source/freshness to expect.

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?

A single, front-loaded sentence with zero waste. It immediately tells the agent what 'this week at a glance' includes.

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 zero-param tool with no output schema, the description must explain return values, and it does list three metrics. However, it leaves ambiguity about what 'best deal' means (highest discount, absolute savings, etc.) and whether 'average savings' is a currency amount or percentage, so it is only partially complete.

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 takes zero parameters, so there is no parameter semantics to explain. The baseline of 4 applies; the description correctly indicates no inputs are needed.

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 names the resource ('this week') and the exact metrics returned: new deal count, best deal, and average savings. It is clear what the tool produces, though it doesn't explicitly distinguish itself from siblings like get_market_overview or list_hot_deals.

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?

There is no guidance on when to use this tool versus alternatives such as get_market_overview, get_market_trend, or list_hot_deals. The phrase 'at a glance' implies a summary use case, but no explicit when/when-not conditions are given.

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