maps_set_transit_time

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

With no annotations, the description carries the transparency burden. It discloses verification steps (mode trigger, transit-time input, route endpoints, directions view) and that a stale replayable navigation action is dropped, plus the requirement for Interactive Assist. However, it does not state the overall side effects or success/failure indicators, leaving some behavior opaque.

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 four sentences, front-loaded with purpose, then constraints, behavior, and a requirement. It contains no filler but is somewhat dense; it could be broken into clearer bullet points, but it remains efficient and well-structured.

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?

The tool has no output schema, no annotations, and 0% schema coverage, so the description must explain the full interaction. It covers purpose, constraints, and process, but it omits what the agent should observe after a successful set (e.g., whether the page updates, any confirmation) and does not mention error cases. This incompleteness may leave the agent unsure of the outcome.

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 0%, so the description must compensate. It does: it explains that expectedOrigin and expectedDestination must match the active request, mode has only two allowed values, and time must be in 24-hour HH:MM. This adds functional meaning beyond the raw schema.

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 sets a same-day depart-at or arrive-by time on a Google Maps transit directions request. It specifies the resource (transit directions request) and the action (set time), and distinguishes it from siblings like maps_set_travel_mode by focusing on transit time rather than travel mode.

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?

It provides explicit prerequisites: expectedOrigin and expectedDestination must match the active maps_directions request, Interactive Assist must be enabled, and mode/time are restricted. It implies when to use it but does not explicitly contrast with alternative tools, though the constraints give clear context.

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