Mark as delivered

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

Annotations already declare the safety profile (not read-only, non-destructive, idempotent, open-world), so the bar is lower. The description adds the useful auto-selection behavior when fulfillment_id is omitted, but does not disclose side effects such as whether a shipping/delivery notification is sent or what error condition arises with ambiguous fulfillment selection.

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 tight sentences, zero filler, and the fallback behavior is front-loaded. Every clause earns its place.

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 mutation tool with no output schema, the description covers the main ambiguity (optional fulfillment_id) but leaves the caller without knowledge of return values, side effects, or behavior when multiple undelivered fulfillments exist. Adequate but with clear gaps.

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 50% — 'order' is documented but 'fulfillment_id' is not. The description compensates by explaining exactly what omitting fulfillment_id does, which is semantic information the schema lacks. This is a genuine addition beyond structured data.

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 ('Marks') and resource ('a fulfillment as delivered'), which clearly separates it from siblings like create_fulfillment and cancel_fulfillment. It does not name a sibling explicitly, but the resource is specific enough to distinguish.

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?

The description gives a conditional rule — omit fulfillment_id to target the single not-yet-delivered fulfillment — which is real usage guidance implied for the caller. It stops short of saying when to prefer this over alternatives like cancel_fulfillment or what error/behavior occurs if multiple undelivered fulfillments exist.

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