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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safe/read-only behavior is covered. The description adds value by disclosing what the returned plan includes—fares, walking legs, transfers, and boarding instructions—which gives the agent useful expectations 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 a single well-structured sentence that front-loads the action and resource, then packs in relevant specifics without any filler. Every phrase earns its place.

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 rich annotations, full schema coverage, and the presence of an output schema, the description is largely complete for correct invocation. It could be slightly stronger with an explicit distinction from plan_trip or mention of trotro-specific limitations, but nothing essential is missing.

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%, with pickup and destination both fully documented as lat/lng coordinate objects. The description does not add parameter-level detail, but it does not need to because the schema already carries the semantic weight.

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 uses a specific verb ('Plan') and resource ('public transport journeys by trotro'), and adds concrete detail about what the plan includes: fares, walking legs, transfers, and boarding instructions. This clearly distinguishes it from siblings like plan_trip and compare_rides by specifying the trotro 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?

The description implies it should be used when the user wants trotro-based public transport planning, but it does not explicitly state when to choose this over plan_trip or when not to use it. No alternatives or exclusions are named, leaving some inference to the agent.

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