RunInstances

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

No annotations are provided, so the description carries full burden. It mentions '批量创建' (batch creation) which implies a write/mutation operation, but doesn't disclose critical behavioral traits: whether this is a destructive operation, what permissions are required, whether it's idempotent, what happens on failure, or what the return format looks like. The description adds minimal behavioral context beyond the basic action.

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 appropriately concise with two sentences. The first sentence states the core purpose, and the second provides usage context. There's no wasted text, though it could be slightly more front-loaded with the primary action.

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 complex mutation tool with 7 parameters, no annotations, and no output schema, the description is insufficient. It doesn't explain what the tool returns, error conditions, side effects, or important behavioral constraints. The agent would need to guess about the operation's consequences and response format.

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 all 7 parameters with Chinese descriptions. The description doesn't add any parameter-specific information beyond what's in the schema. With high schema coverage, the baseline is 3 even without additional param details in the description.

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's purpose: '批量创建ECS实例' (batch create ECS instances). It specifies the verb (create) and resource (ECS instances), and mentions the batch aspect. However, it doesn't explicitly differentiate from potential sibling tools like 'StartInstances' or 'DescribeInstances' beyond the creation focus.

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 provides some usage context: '适用于需要同时创建多台ECS实例的场景，例如应用部署和高可用性场景' (suitable for scenarios requiring simultaneous creation of multiple ECS instances, such as application deployment and high-availability scenarios). This gives implied guidance about when to use it (batch creation scenarios) but doesn't explicitly state when NOT to use it or mention alternatives like creating single instances via other means.

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