A shop's phone price list

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

Annotations already cover safety (readOnly, idempotent, non-destructive), so the description's job is to add context — and it does, disclosing that phone numbers and e-mail are withheld and that `shop_url` exposes them on the site. That is a real, non-obvious output limitation. It doesn't discuss pagination limits or error behavior, keeping it just short of a 5.

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?

Three tight sentences: what it does first, usage triggers second, caveat last. No filler, no restatement of the title, and the sibling routing is placed where an agent will read 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?

For a 4-parameter read-only lookup with no output schema, the definition covers purpose, selection criteria, the alternative tool, and the notable omission of contact details. A brief note on result ordering or typical volume would make it fully self-sufficient.

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 coverage is 100%, so page, brand, shop_id and name_contains are already documented in the schema. The description adds only the currency unit (Toman) and a hint that shop_id comes from mi_options('shops') or mi_shop_prices — useful but marginal. 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: 'Show one Mobile.ir shop's profile and the phones it lists with their current prices in Toman.' The scope ('one shop') is explicit and immediately distinguishes it from the sibling mi_shop_prices, which is named.

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?

Gives concrete when-to-use triggers ('what does shop X sell', comparing a shop's prices for a brand) and an explicit routing rule: 'For one model across all shops use mi_shop_prices.' That is the when/when-not/alternative pattern at full strength.

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