uplus_login

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

With no annotations present the description carries the full burden and does so: it discloses that auto mode prompts the user for credentials, that credentials are used only for this call and never persisted to config, reports or logs nor echoed back, that the visible browser window is handed to the user on fallback, and what the call returns. This is security- and side-effect-relevant context an agent cannot derive from the schema.

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 critical instruction to ask the user first and the mode parameter are front-loaded, with the per-mode behavior in tight bullets. Every sentence earns its place: purpose, mode semantics, fallback triggers, credential handling, return shape.

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?

Although no output schema exists, the description names the return fields (logged_in, chosen mode, current URL, token length), and covers the risky auto-mode path thoroughly. The only real omission is what wait_timeout_ms controls and what happens when it expires.

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 0%, so the description must compensate, and it does for mode (two named values with distinct semantics), username, password and school (all only meaningful in auto mode, retrieved from the user). wait_timeout_ms is never mentioned anywhere, leaving one of five parameters entirely unexplained.

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?

States a specific verb and resource: 'Sign in to U+ through the attached browser session'. The two modes are enumerated precisely, so what the tool does is unambiguous. It never mentions the sibling uplus_check_login, so an agent gains no explicit signal about when to verify an existing session versus create one.

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?

Explicitly instructs the agent to ask the user which flow they prefer BEFORE calling, and gives the selection criteria for each: manual when no credentials should be handled, auto when the user supplies account/password/school. It further states concrete fallback triggers (field not found, school unmatched, captcha/SMS/wrong-password) that route the call back to manual, which is exactly the when-not guidance most definitions lack.

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