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

Annotations already declare destructiveHint=true, idempotentHint=false and openWorldHint=true, so the safety bar is lowered. The description still adds meaningful context beyond them: the required prior state (stopped/pending) and the warning that starting can enable live trading, i.e. real-money execution. It stops short of describing failure behavior for an already-running instance.

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 tight sentences with zero filler; the action and its precondition are front-loaded, and the sibling caveat follows. 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?

With an output schema present, return values need not be explained. The description covers action, precondition, side effect, and sibling scope, but omits what happens on invalid state (e.g. instance already running) or permission requirements for enabling live trading.

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?

Single parameter with 100% schema description coverage, so the schema already documents instance_id fully. The description adds no format, range, or lookup guidance beyond what the schema provides; 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+resource (start ... instance) plus the precondition state (stopped/pending) and the notable side effect (can enable live trading). It also names two siblings it is not a substitute for, so an agent can distinguish it from activate_algo and create_instance without opening either 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?

The description gives an implied usage condition (instance must be stopped/pending) and a negative exclusion (does not replace activate_algo or create_instance), but never states positively when to choose this over siblings like create_and_start_algo, which also starts execution. Guidance is inferable rather than explicit.

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