maps_directions

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

Annotations already declare readOnlyHint=true, so the read-only safety profile is covered. The description adds behavioral context about live traffic being available for motorised modes, and notes that setting include_steps=false is 'cheaper'—useful cost/performance information beyond the annotations.

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 three sentences long, front-loads the core purpose, and packs in essential capabilities without fluff. Every sentence earns its place, making it concise and well-structured for an 18-parameter tool.

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?

Given the high complexity (18 parameters, no output schema), the description partially covers what the tool returns—turn-by-turn steps or total time and distance—but does not describe the full response structure, alternative route behavior, or other return fields. While input semantics are well covered, the return value gap makes it incomplete.

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 100%, so the baseline is 3. The description adds some clarification about accepted formats for origin/destination/waypoints and that include_steps=false gives totals, but much of this is already present in the schema. It does not provide significant additional meaning beyond structured definitions.

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 clearly states the tool computes a route with turn-by-turn steps, listing supported travel modes and key features like live traffic and avoidance options. This specific verb+resource distinguishes it from sibling tools such as maps_distance_matrix or maps_geocode.

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 context for the tool's main use (route computation with optional waypoints and modes) but does not explicitly mention when to use it over alternatives like maps_distance_matrix. The note 'Set include_steps=false when only total time and distance matter' is a parameter-level hint, not a tool-level alternative.

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