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

Annotations already declare readOnlyHint=true and destructiveHint=false; the description reinforces and explains this by framing the call as a proposal with an explicit save step, and discloses the access scope and underlying endpoint. It adds real value on side-effect boundaries but says nothing about cost, latency, or limits on large route sets.

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?

Three dense sentences: purpose first, then the side-effect boundary and follow-up tool, then the access and endpoint. No filler, and the most decision-relevant facts are front-loaded.

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 12-parameter, five-required planning call with no output schema, the description covers the intent, the mutability contract, and the shape of the result well enough to invoke correctly. Minor gaps remain around the sizing parameters (num_placeholders, max_stops_per_route) that carry no schema description.

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?

With 83% schema coverage the baseline is 3, and the description earns an upgrade by explaining the otherwise ambiguous relationship between input_route_ids and output_route_ids ('stops move between the output routes'). It also names the result payload components (times, distance, unassigned stops) that correspond to the planning inputs.

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 and resource — 'Generate a proposed re-sequencing of the stops of existing routes for one route date' — and clarifies the distinctive mechanic that stops move between output routes. It does not explicitly contrast with the sibling cxt_optimize_route_plan, so an agent must infer the difference from the word 're-sequencing' versus optimization.

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?

Gives clear context: this is a proposal, 'nothing changes until cxt_save_route_plan is called', which names the follow-up sibling and establishes the plan/save workflow. Also states the required scope ITINERARY_PLANNING_ACCESS as a precondition. It stops short of naming when to prefer this over cxt_optimize_route_plan or cxt_plan_orders.

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