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

Annotations already declare read-only, idempotent, non-destructive and closed-world, and the description adds real behavior beyond them: empty list means no linked account, missing linked account raises a sign-in error, results are newest-first, no paging exists. For a read tool this is unusually rich.

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?

Every sentence earns its place: usage trigger, parameter semantics, edge cases, then sibling routing. Front-loaded with the when-to-use clause and no filler.

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?

Output schema exists so return values need no explanation, yet the description still calls out the can_return field. Combined with error and empty-list behavior, an agent has everything needed to invoke and interpret this 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 coverage is 100% so the baseline is 3, but the description adds meaning the schema lacks: newest-first ordering, the 1-20 bounds restated, and the rationale for raising limit. It does not add format or edge-case detail beyond that, so it sits just above baseline.

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 ('asks about their recent teas.co.uk orders') and scopes it to a signed-in customer. The niche is immediately distinguishable from siblings like my_subscriptions or view_basket.

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?

Explicitly routes to alternatives with conditions: track_order for one order, reorder to buy again, start_return to return items. It also states when to raise limit ('only when the customer asks about older orders') and that there is no paging.

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