E-commerce

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

Annotations provide readOnlyHint=true, so the description doesn't need to restate that. The description adds content specifics (revenue/order overview, best-selling products by product name, SKU, or category), which is useful beyond the schema's enum values. It doesn't contradict annotations, and it doesn't mention any side effects or limitations, but that's acceptable given the read-only hint.

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, concise sentence that front-loads the core purpose. Every word adds value without redundancy or fluff.

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 the readOnlyHint annotation and full schema coverage, the description is adequate. It explains what the tool returns (revenue/order overview and best-selling products) but doesn't mention any special behaviors like date filtering or segment support, though these are covered by parameters. The lack of an output schema means the agent must infer return format, but the description gives a reasonable overview. Overall, it's sufficient for a read-only reporting tool.

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%, so parameters are already well-documented. The description adds minimal extra semantics beyond restating the report types (overview, products, skus, categories) which are already in the 'report' enum. Thus, it meets the baseline of 3 for full coverage but doesn't add significant value beyond the schema.

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 clearly states the tool's function: 'E-commerce performance: revenue/order overview, and best-selling products by product name, SKU, or category.' This specifies the resource (e-commerce performance) and the scope (revenue/orders, products, SKUs, categories), and distinguishes it from siblings like matomo_pages or matomo_goals by focusing on e-commerce-specific metrics.

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 implies when to use (for e-commerce performance data) but does not explicitly contrast with alternatives or provide exclusions. It doesn't say 'use this for e-commerce analytics, use matomo_goals for goals' etc. The clear purpose gives context, but no explicit guidance on when not to use it.

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