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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=true, so the safety profile is covered. The description usefully signals that extra sub-resources are opt-in, but it never says that toggling those flags increases payload size or latency, nor anything about error behavior for a missing id.

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 short sentences with the core action (one product by id) front-loaded and the expansions following. The trailing REST endpoint adds minor navigational value and costs almost nothing.

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 7-parameter read tool with only one required argument, full schema coverage and no output schema, the description conveys the shape of the call adequately. The loose naming of some optional expansions is the only real gap an agent could stumble on.

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 the schema already documents every flag, and the baseline is 3. The description's enumeration mostly mirrors the flags, with slight drift — it mentions "bundled items" and "reserved stock" while the actual parameters are with_reserve_items, with_inventory_reservations and with_attribute_items — so it adds little precision 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 states a specific verb and resource — fetch one product by id — and lists the optional sub-resources that can be pulled in. It implicitly contrasts with smaregi_list_products ("one product" vs. a list) but never names that sibling, so differentiation is inferential rather than explicit.

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?

Using this for a single known id is strongly implied, and the optional with_* expansions hint at a fetch-what-you-need pattern. There is no explicit statement of when to prefer smaregi_list_products or the update/create siblings, and no guidance on when to leave the expansion flags off.

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