route

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false. The description adds the specific behavioral claim that the tool only suggests an action and never executes it, which is useful context beyond the generic read-only hint. It does not contradict 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 compact, front-loaded with the core use case, and contains no filler. Every sentence contributes: the first defines when to use it, the second defines when not to and names alternatives, and the third reinforces the no-execution behavior.

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 description fully covers intent and selection among siblings, and output schema exists to explain return values. However, with four input parameters, nested objects, and zero schema descriptions, the lack of guidance on how to construct state, actions, and instructions leaves a meaningful gap for an agent invoking the tool correctly.

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 by explaining parameters. It only hints at 'a closed set of actions', which maps loosely to the actions parameter, but it does not explain the meaning or expected use of state, instructions, model, or how action values are interpreted.

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 states a specific purpose: choosing exactly one next action from a closed set of actions. It also distinguishes itself from siblings by explicitly excluding classify (topic/category label) and score (ordered rating), and clarifies it never executes actions.

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 USE WHEN and DO NOT USE WHEN guidance, names concrete alternatives (classify, score, action execution), and tells the agent that action routing should use this tool while execution should not. This is strong usage direction.

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