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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false. The description adds valuable context about the computation scope (date range, default last 30 days) and report contents (coverage of catalogue, units, revenue, margin distribution, missing-cost products), which enriches behavioral understanding beyond the annotations.

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?

The description is a single, well-structured sentence that front-loads the core action ('Report how much... is covered') and efficiently includes key output dimensions. No filler or redundant phrases.

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?

Given an output schema exists and parameters are fully documented, the description provides a sufficient overview of the report's scope and contents. It could mention edge cases or data handling, but these are not necessary for correct invocation given the rich schema and annotations.

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 100%; both start_date and end_date are fully documented with formats, defaults, and timezone behavior. The description only restates the default date range and adds no further parameter-level meaning, so the baseline score of 3 is appropriate.

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: 'Report how much of the store's catalogue, units sold, and revenue is covered by COGS data.' It also details output components (margin distribution, top missing-cost products), making it clearly distinct from siblings like get_item_cogs or list_cogs that likely return raw COGS data.

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?

No guidance is provided on when to use this tool versus alternatives such as find_cogs_gaps or get_item_cogs. The description implies it is a coverage overview but does not state conditions or prerequisites for choosing it.

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