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

Goes well beyond annotations: it discloses PATCH partial-update semantics, the destructive REPLACE behavior of driver_ids, the writability precondition, and — importantly for a destructiveHint=true tool — that nothing is sent to drivers, scoping the blast radius. It stops short of naming required permissions/roles or any side effects on dependent stops and routes.

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 short sentences, front-loaded with the WRITE marker and mutation scope, then the replace-semantics gotcha, then the failure condition. Zero filler.

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 destructive, non-idempotent mutation with no output schema and sparse parameter documentation, the description covers the essentials: what changes, what gets replaced, when it fails, and the absence of driver notification. It omits what happens to existing stops/routes when depot_id changes and gives no auth/permission guidance.

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 only 20% schema description coverage, the description must carry the load, and it does map its prose fields (title, date, drivers, depot) onto title/starts_on/driver_ids/depot_id and clarifies driver_ids replaces the whole list. However, plan_id, date format expectations, and depot-change consequences are left entirely to the schema's bare type/pattern declarations.

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?

Opens with a specific verb+resource ("change a plan's ...") and enumerates exactly which fields are mutable, which cleanly separates it from spoke_create_plan, spoke_distribute_plan and spoke_get_plan. The PATCH endpoint reference removes any ambiguity about the operation type.

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 a clear when-to-use context (editing an existing writable plan) and a when-not condition ("Fails if the plan is not writable (already distributed)"). It does not explicitly name spoke_distribute_plan or another sibling as the alternative path, so routing is implied rather than stated.

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