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 description does not need to repeat safety. The description adds 'Local, free, side-effect-free' which provides useful behavioral context beyond the annotations, emphasizing it does not have external side effects. It also clarifies it's a router with no side effects on data, adding value.

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 two sentences, front-loaded with the core purpose and example, then adds the 'Local, free, side-effect-free' qualifier and its role in workflows. No wasted words; it's efficient and easy to parse.

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 conditional router with no output schema, the description covers all that an agent needs: it explains the purpose, the comparison mechanism, and the routing outcome. The schema details the parameters, and the annotations cover side-effects. No gaps for correct invocation.

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%, so the schema already documents each parameter well. The description adds context by explaining the abstract meaning of left/right as 'values from previous steps' and shows an example of operator usage. However, it does not detail the specifics of each operator (e.g., 'contains' behavior) or how to reference previous step values, but since the schema covers basic semantics, a 4 (above baseline 3) is justified for the added example and conceptual framing.

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 clearly states the tool is a router/IF-ELSE block that compares two values and routes down True or False branches. It names the specific verb 'compare' and the resource (values), and provides a concrete example (invoice amount > 1000), making it easy to distinguish from siblings that perform financial analysis or file processing.

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 gives clear context for when to use it: for conditional branching in automations. It does not explicitly state when not to use it or name alternative tools, but the phrase 'building block for conditional automations' implies its role as a control-flow tool, which is distinct from the sibling tools that are all domain-specific actions. Exclusions are lacking, so a 4 is appropriate.

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