ncloud_update_policy

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

Annotations only provide idempotentHint and destructiveHint, which are somewhat generic. The description adds critical behavioral context: the permissions array REPLACES existing statements, meaning the agent must send the complete set. It also discloses constraints about system-managed policies and name immutability, which go beyond annotations and are essential for correct invocation.

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 sentences, front-loaded with the most critical information (replacement semantics and prerequisite read). No filler words; every sentence earns its place and is logically ordered.

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?

Despite the complex nested parameter structure, the description covers all critical usage constraints: replacement behavior, need to read first, system-managed restrictions, and name immutability. It is complete for an agent to correctly invoke the tool without additional documentation. The absence of an output schema is fine since the tool's purpose is an update action.

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. The description adds value by emphasizing the replacement behavior for the permissions array, which is not fully obvious from the schema alone. It also provides context on how to obtain the current statements (read with ncloud_get_policy_detail), indirectly guiding construction of the permissions parameter. This raises it above the baseline but not to a 5 since the schema already describes each parameter.

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 action ('Update a user-created (custom) IAM policy'), identifies the specific resource (custom IAM policy), and immediately distinguishes it from system-managed policies. It also differentiates from sibling tools like ncloud_get_policy_detail and ncloud_create_policy by its explicit focus on updating and the replacement semantics.

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?

Provides explicit guidance: read current policies with ncloud_get_policy_detail first, warns that system-managed policies cannot be updated, and notes the policy name cannot be changed. This gives clear when-to-use and when-not-to-use guidance, effectively routing the agent to the correct workflow.

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