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

Annotations already cover the safety profile (readOnlyHint=false, destructiveHint=false, idempotentHint=false), so the description's job is to add context — and it does: it enumerates what each profile actually monitors (cold_chain MKT, high_value chip-verified custody at every handoff, etc.) and discloses the return ('the shipment id and the thresholds that will judge it'). It does not explicitly warn that repeated calls create distinct shipments despite idempotentHint=false.

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?

The purpose is front-loaded in the first clause, followed by profile semantics and then input requirements and return value. The single dense paragraph has no filler sentences, though the profile enumeration is long enough that it slightly buries the parameter guidance mid-block.

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 9-parameter tool with nested objects and no output schema, the description covers the highest-risk semantics (profile thresholds, coordinate format, item identifiers) and does describe the return value. It is thin only on the low-risk optional fields (carrier, planned_arrive/depart) whose schema descriptions already say ISO 8601.

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 only 44%, so the description has to carry weight — and it does: it explains all six profile enum values with their physical meaning, states that origin/destination require decimal-degree coordinates, and notes items may carry chip uid, GTIN, lot and serial, plus that thresholds override profile defaults. Carrier, reference, and the planned_* dates get no added meaning, leaving a modest gap.

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 opens with a specific verb and resource — 'Register a shipment of physical items under a sensitivity profile' — and states the operational intent ('so Aeroz can watch it in transit'). That is enough to separate it from siblings like list_shipments, shipment_status, or plan_route without opening any schema.

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?

Usage is implied by the purpose statement rather than stated: an agent can infer this is the creation step before shipment_status/log_telemetry apply. However, no sibling is named, no when-not condition is given, and prerequisites (e.g., whether profiles must be inspected via shipment_profiles first) are not mentioned.

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