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

Annotations already declare readOnly/non-destructive, so safety is covered; the description adds real behavioral context — the two service tiers, the 2-hour metro rush, freight quoted at checkout, and the free-delivery threshold on local orders. It stops short of covering rate limits or exact fee values, but for a read-only lookup that's minor.

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?

Front-loads the core contract (city in, options with ETA/cut-off/fee out) in the first sentence, then layers geography and fee rules. Slightly long and the sample questions are decorative, but every sentence carries usable information.

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?

With no output schema, the description fully carries the return contract (ETA, cut-off time, CAD fee) plus the regional behavior that determines the answer's shape. An agent has everything needed to call this correctly and interpret the result.

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 city, province and orderSubtotalCAD are already documented with examples; the description roughly restates the province guidance rather than adding new syntax. Baseline 3 applies since the schema does the heavy lifting.

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 concrete verb+resource (return MapleV's delivery options) and a precise geographic scope (any city in Canada), then names exactly what comes back: ETA, cut-off time, CAD fee. The local-area vs. rest-of-Canada split further distinguishes it from the catalog siblings, which do entirely different things.

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 explicit when-to-use framing via two sample questions ('can MapleV get this part to my shop in Abbotsford today?', 'how long does shipping to Calgary take?') and tells the caller when the province argument matters. It doesn't name alternatives, but the sibling tools (get_part, search_parts, list_categories) aren't competing for this task, so routing guidance is sufficient.

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