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

The CONFIRMATION paragraph discloses behavior that annotations cannot express: this tool is proposed, never executed directly, returns status='confirmation_required' with an action_id and plan_token, and the write only lands after confirm_action. That is exactly the two-phase write protocol an agent must know to avoid assuming the unit exists after this call. Annotations only say readOnlyHint=false and destructiveHint=false, so the description is adding substantial value.

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-loaded with the core action, then the kind-specific field mapping, then the confirmation protocol last — a sensible ordering. The parenthetical vehicle/trailer clauses are dense and read as a run-on, but every clause carries actionable field information rather than 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?

For a 17-parameter creation tool with no output schema, the definition supplies the two pieces an agent most needs: how to branch on 'kind' and how the confirmation handshake works. It is not fully complete — several optional identifiers (carrier_id, default_driver_id, status) and their preconditions go unmentioned — but nothing essential to invoking it correctly is missing.

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 29% across 17 parameters, so the description carries real weight and largely delivers: it maps vehicle_type, trailer_type, capacity_t, volume_m3, axles, vin, color, registration_certificate, and both service/inspection dates to the correct kind. It leaves brand, model, status, carrier_id, and default_driver_id unexplained, which is a notable residual gap given the low schema coverage.

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?

Opens with a specific verb+resource ('Add a fleet unit') and immediately disambiguates the two entity kinds it can create, including which type-specific fields apply to each. It never names logistics_update_fleet_unit or logistics_list_fleet, so the create-vs-update distinction is left implicit, but the purpose itself is unambiguous.

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 clear internal routing guidance for the 'kind' enum (vehicle vs trailer, with the matching field set for each), which tells the agent how to call it correctly. What it lacks is tool-selection guidance: no statement of when to use this versus logistics_update_fleet_unit, or any prerequisite such as needing carrier/driver records to already exist for carrier_id and default_driver_id.

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