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

Annotations already cover readOnly/idempotent/non-destructive/openWorld=false, yet the description adds substantial extra context: the non-storefront error shape, that the MCP Apps panel is display-only and never places an order, that image_url is null when absent, and the Com/$ conversion rate. This goes well beyond the safety profile.

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?

Purpose and scope are front-loaded and readable, but there is real duplication: the return shape is given once in prose and again in a Returns block, and the not_a_storefront error is stated twice. The unexplained "CO 607-002" reference also spends space without earning it.

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?

There is no output schema, so the description correctly carries the full return contract (field list and structuredContent), the error case, and the interactive-panel behavior. Nothing an agent needs to invoke or interpret this tool is missing.

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?

Only one parameter with 100% schema coverage, and the schema already documents tenant_id with the same "earth" example the description repeats. The description adds no format or constraint detail beyond the schema, so the baseline 3 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?

States a specific verb and resource — showing a store's public product catalog — and enumerates the exact per-product fields returned. An agent can tell this is a storefront read, distinct from the agent/platform catalog siblings, though no sibling is named explicitly, which keeps it off 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 tells the agent to pass tenant_id (e.g. "earth") and notes the tool is public/read-only/free, which implies usage. But it never states when to choose this over federation_offer, federation_pricesheet, or the federation_catalog_* siblings, so guidance remains implied rather than explicit.

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