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

Annotations already declare readOnlyHint=false, destructiveHint=false, openWorldHint=false, so the safety profile is covered. The description adds a genuinely useful behavioral note ('v0.5 is SDK-only and uses manual promote/rollback'), but omits what starting actually does (traffic begins flowing), whether it is reversible without rollback_production_test, and the superadmin requirement implied by customerId.

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 the core action front-loaded and zero filler. The second sentence is terse to the point of being cryptic ('v0.5 is SDK-only'), but nothing is wasted.

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 six-parameter mutation tool with no output schema, the description is thin: it never says what the tool returns, what happens to live traffic afterward, or how the test is later ended. Schema carries the parameter detail, so this is adequate but with clear gaps.

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 coverage is 100%, so all six parameters including the scoreDefinition enum and traffic defaults are already documented in the schema. The description only reinforces that processId refers to a *completed* optimization, adding marginal meaning over structured data. Baseline 3 applies.

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 ('Start a production A/B test') plus the precondition ('for a completed optimization'), so the agent knows this launches a live test rather than simulating one. It does not name or differentiate itself from close siblings like simulate_ab_test, start_model_test, or promote_production_test.

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 phrase 'for a completed optimization' gives an implicit precondition, and 'manual promote/rollback' hints at the lifecycle. But there is no explicit when-to-use versus simulate_ab_test (offline) or start_model_test, and no statement of what must be true before calling.

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