Driving route with live traffic

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

With readOnly/idempotent/openWorld already declared by annotations, the description still earns credit by disclosing return cardinality (up to 3 routes, suggested first), the meaning of `notes` labels (traffic delay, toll in Toman, fuel use), the conditional `traffic_plan` for restricted zones with hours, and the semantics of the 'no route' error (point outside Iran or off road network). That is behavioral context the annotations cannot carry.

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 capability, then tiers into return shape, zone behavior, and error cases. Dense but nearly every clause carries information; the parenthetical Persian terms (طرح ترافیک, زوج و فرد) are the one place where length slightly outruns payoff for a non-Persian agent.

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?

There is no output schema, yet the description fully specifies the response shape (routes array, notes labels, traffic_plan, legs) and the main failure mode, so an agent can both call it correctly and interpret what comes back. Nothing material is left to guess.

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 baseline is 3, but the description adds real meaning: `stops` produce per-part `legs`, and `traffic_plan` is what surfaces when a stop or endpoint enters a restricted zone. `steps` is not discussed in prose, which keeps it off a 5.

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 ('Get driving routes in Iran') plus the payload dimensions (distance, travel time in current traffic, tolls, roads, zone warnings). The Iran scope and driving-only constraint separate it from the coordinate-lookup and proximity siblings without needing their schemas.

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 an explicit prerequisite chain: 'Get coordinates from bl_search or bl_nearby', which names concrete alternatives an agent needs before calling. It also states when the tool is inappropriate in spirit ('Driving only: Balad's routing answers car routes for every mode'), though it never contrasts with bl_nearest_by_drive or bl_along_route, which is the likeliest sibling confusion.

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