check_route

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

Annotations already provide readOnlyHint=true, so the read-only safety profile is covered. The description adds genuinely useful behavioral context: the 1-minute refresh for CHIP incidents vs 5-minute cache for closures/chain controls/fires, the clipping behavior of coordinates to the driven span, and the limitation that it cannot forecast future conditions. It does not overclaim, and it explicitly disclaims forecast ability. Small deduction because it doesn't state the exact 'within ~10 miles' definition precisely or say what the summary contains, but the annotation coverage lowers the burden and it still adds solid 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?

The description is long but every sentence earns its place: core purpose in the first sentence, the flagship positioning, concrete result content, a clear imperative about coordinates, covered corridors, an explicit non-goal, fallback instruction, and freshness. The most critical instruction (ALWAYS pass coordinates) is front-loaded immediately after the what-it-does. Structure is scannable with clear paragraphs. No filler or repetition.

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 tool with 4 parameters, 0% schema coverage, no output schema, and 10 siblings, the description is remarkably complete: it covers what the tool returns, the geographic scope, coordinate behavior, freshness semantics, fallback behavior, and explicit exclusions. The agent has enough to decide when to pick it and how to call it correctly. The response shape is described at a sufficient level (list of incident types plus summary) even without an output schema.

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 0% so the description must carry the meaning of each parameter, and it does: it explains that from_coords and to_coords are 'lat,lon' strings, optional but recommended, and describes exactly what they do (resolve unlisted places and CLIP the route span). It also clarifies the meaning of from_place and to_place by context ('start and end place'). This far exceeds the schema's bare string properties and fully compensates for the 0% 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?

The description is explicit: 'Check current conditions along a major California highway corridor' and positions the tool as 'The flagship trip-check tool.' It names the resource (major CA highway corridors) and the verb (check current conditions) and specifies the kinds of results returned (CHP incidents, lane closures, chain controls, wildfires), distributed from a list of covered corridors. This clearly separates it from siblings like get_incidents, get_lane_closures, etc.

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 explicit guidance: 'ALWAYS pass from_coords and to_coords... when you know where the places are' and 'for landmarks, small towns, or anything not a major city they are required for a good answer.' It also says when NOT to use the tool: 'This is NOT a general router... fall back to the filtered tools with center= for anything else.' That is direct and actionable, and it names the sibling categories to use as fallback.

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