h3yun_login

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

With no annotations provided, the description carries the full behavioral burden. It conveys that login is a prerequisite and establishes some session context, but it does not disclose session lifecycle, idempotency, re-login behavior, or failure semantics. This is adequate for a straightforward login tool but leaves typical behavioral questions unanswered.

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 concise sentences with no filler. The core action is front-loaded, and the critical usage condition ('Required before other tools') appears in the first sentence. Every word 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?

The tool is simple, all parameters are documented in the schema, an output schema exists, and usage context is clear. The only omission is a note about what happens on repeated login or if a session already exists, but this is minor given the simplicity and the presence of structured schemas.

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 already documents all three parameters including the optional engine_code. The description names 'mobile and password' but adds no new meaning beyond the schema. Baseline 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 verb ('Sign in') and resource ('H3 Yun') with the authentication method ('mobile and password'). It clearly distinguishes this tool from the sibling tools, which are post-login operations like listing apps/forms or querying records.

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 explicitly positions the tool as a precondition: 'Required before other tools unless env credentials are set.' This tells an agent when to invoke it and when it can be skipped, which is direct usage guidance.

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