eda_sys_storage_get_extension_user_config

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It explicitly discloses that the tool throws an Error in standalone script environments and returns `undefined` when the configuration item does not exist. These are meaningful behavioral traits beyond what the schema alone provides, though it does not discuss side effects (likely none for a getter).

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 compact and well-organized with labeled sections: signature, one-line summary, remarks, and returns. Every line earns its place; there is no filler or repetition of schema content. It could be slightly more natural-language oriented, but overall it is appropriately sized.

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 simple getter with no output schema and no annotations, the description provides the essential return type (`any | undefined`), the missing-key behavior, and the environment restriction that causes an exception. An agent has enough information to decide whether to call it and what to do with the result. A concrete example or a note about the shape of stored values would push it higher, but they are not essential here.

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%, but the `args` items are untyped `{}`, so the description's signature `key: string` supplies critical type information for constructing the argument array. Combined with the schema's note that args follow the official signature order, an agent can confidently map the first argument to a string key. The optional `windowId` parameter is adequately described in the schema itself.

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 opens with the exact API signature `sys_Storage.getExtensionUserConfig(key: string) -> any | undefined` and the Chinese summary `获取扩展用户配置` (get extension user configuration), which clearly identifies a getter for a single configuration value by key. This implicitly distinguishes it from sibling `get_extension_all_user_configs` by showing the key parameter, though it does not name the alternative explicitly.

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 remarks provide decisive usage context: `本接口仅扩展有效，在独立脚本环境内调用将始终 throw Error` (only valid in extensions; calling in a standalone script environment will always throw). This tells the agent when NOT to use the tool. However, it does not mention when to prefer this tool over related storage siblings like `get_extension_all_user_configs` or `set_extension_user_config`.

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