modify_user

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

The annotations already convey that this is a destructive, non-idempotent mutation (readOnlyHint=false, destructiveHint=true). The phrase 'Changes state on Growatt's side' adds only modest context about external persistence; it does not describe specific consequences such as overwriting the old number or downstream effects.

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 short sentences with no filler. The primary purpose is front-loaded, and the second sentence adds a meaningful behavioral note about external state changes without redundancy.

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 two-parameter update with a clear schema, an output schema, and annotations covering mutability, the description is largely sufficient. It could be improved by stating that the target user must already exist, but the c_user_id schema description referencing list_users already hints at this.

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 fully documents both parameters. The tool description adds no additional meaning about c_user_id or mobile beyond what the schema already provides, so the baseline score of 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?

The description states a specific action ('Update') and a specific resource ('end-user's mobile number'), which clearly distinguishes it from sibling tools like register_user, check_user, and list_users. Although the tool name is generic, the description narrows the scope to a single field update.

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 implies usage: use it when you need to change an end-user's mobile number. However, it does not explicitly state when not to use it or name alternatives such as register_user for creating users, leaving the routing decision to inference.

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