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

Annotations already declare write (readOnlyHint=false), non-idempotent, non-destructive, open-world. The description adds real behavioral context beyond that: the instance is created in a default 'pending' state and only runs immediately when explicitly requested. It still doesn't say what happens on failure or duplicate names, which would be needed for a 5.

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?

Three tight sentences, front-loaded with the core action and its required input, followed by the two behavioral rules. No filler and nothing redundant with the title.

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?

An output schema exists, so return values need not be described. The description covers the required linkage, default state, and conditional start flag, which is sufficient for a 4-parameter create tool; only marginal gaps remain (no mention of permission requirements or behavior on name collisions).

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 baseline is 3, but the description adds decision semantics for start_immediately (only when user wants live now) and clarifies broker_account_id is the internal id sourced from list_brokers rather than an external account number. That goes beyond the field-level descriptions.

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 (create) and resource (trading instance), names the linking key broker_account_id and its source tool (list_brokers), and pins the default state (pending). An agent can distinguish this from create_algo, create_and_start_algo, and create_instance's siblings without opening a 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 explicit conditional guidance: 'Prefer paper/demo unless user chooses live' and 'start_immediately=true only when user wants live now', which tells the agent when to set the risky flag. It does not, however, route to a named alternative such as create_and_start_algo or explain the relationship to start_instance, so it stops short of full when/when-not coverage.

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