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

Annotations already establish readOnlyHint and openWorldHint, and the description adds genuine behavioral context beyond them: what each route contains (distance, live/historic durations, toll/highway flags, traffic note, turn-by-turn steps) and that detail=full adds the path. It does not cover error/permission conditions, but the return-content disclosure is substantive.

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?

A single dense sentence that front-loads the core purpose (directions between origin and destination) before the return-value detail. Every clause contributes, though it packs a lot into one sentence rather than structuring output details separately.

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?

With an output schema present and 100% parameter coverage, the description only needs to orient the agent, which it does by summarizing the returned route fields. The main gap is the absence of sibling differentiation, which matters given apple_maps_eta and transit variants.

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 all 13 parameters are already documented at the source. The description restates mode options quoted, detail=full, and toll/highway flags, adding slight emphasis but no syntax or semantics beyond the schema; baseline 3 is appropriate.

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 (directions) and resource (routes between origin/destination with optional stops for driving/walking/cycling), and enumerates the returned fields. Very clear what the tool does, but it never mentions or distinguishes from siblings like apple_maps_eta or apple_maps_transit_departures, which overlap in purpose.

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?

No explicit when-to-use or when-not guidance. The mention of detail=full adding the path and the mode/avoid options imply how to shape a call, but there is no routing advice against the eta or transit siblings that an agent would benefit from.

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