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

Annotations only declare readOnlyHint=false and openWorldHint=false, i.e. a local mutation; the description adds real behavioral context beyond that: the group must already exist, and a null groupId extracts routes rather than assigning them. It stops short of stating whether the move replaces existing group membership, whether the call is idempotent, or what permissions are required.

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?

Two short sentences with no waste: the operation and its two modes come first, and the prerequisite follows. Every clause carries information an agent needs before calling.

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 two-parameter mutation with full schema coverage and no output schema, the description covers the mode distinction and the prerequisite, which is most of what an agent needs. Remaining gaps are outcome details: behavior when a route is already grouped elsewhere and failure or permission conditions.

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%, and the schema already documents routes and the groupId null alternative, so the description mostly restates the null semantics rather than adding new meaning. It does reinforce the dual interpretation of groupId, but that is the baseline expectation when the schema already does the heavy lifting.

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 ('переносит ... маршруты в ... группу') and covers both operating modes in one sentence: assignment to an existing group or removal via groupId = null. An agent can distinguish this from route_change_target, route_create, or group_create without opening the schema.

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 an explicit prerequisite: a new group must first be created with group.create, which prevents the common error of passing a non-existent group. It also states the null case as the removal path. It does not, however, say when to prefer this over adjacent tools such as route_show or route_change_target, nor what happens if a route already belongs to another group.

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