iptime_login

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

Annotations already signal a state-changing operation (readOnlyHint=false, openWorldHint=true, idempotentHint=false). The description adds a valuable behavioral constraint beyond annotations: credentials are never accepted as tool arguments, telling the agent not to attempt to pass username/password. It does not disclose failure behavior or session details, but the bar is lower given annotation coverage.

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 action is front-loaded, and the critical constraint about credentials is stated immediately after. Every sentence earns its place.

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 login tool with no output schema, the description is minimally sufficient: it states the authentication source and the schema covers the two optional parameters. However, it omits what a successful login returns, whether a session is established, and how failures or pre-existing sessions are handled. Given the openWorldHint and mutation nature, this is a clear gap.

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?

The schema already provides strong descriptions for both parameters, including when captcha_code is needed and when router_id is optional. The description adds extra semantic value by explicitly clarifying that no credential parameters exist, which directly informs how the agent should reason about the input schema and why required auth fields are absent.

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 uses a specific verb ('Authenticate') and a clear resource (the router, implied by the iptime naming and sibling set). It also draws a meaningful distinction from typical authentication tools by stating that credentials come from the MCP environment and are never accepted as arguments, which clearly separates it from any hypothetical credential-input tool.

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 does not state when to use this tool versus alternatives, nor does it mention exclusions or prerequisites. It does not say 'use before other operations' or contrast with logout. The only usage hints live in the schema parameter descriptions (captcha only after requested, router_id optional when exactly one router exists), not in the description itself.

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