start_login

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

Annotations only provide a coarse safety profile (non-readonly, open-world, non-destructive). The description adds meaningfully more: the returned value is an opaque login_id, the call is idempotent-ish ('Reuses an active attempt without opening another page'), and it explicitly discloses what is NOT returned ('Never returns a token or private handoff link'). That is exactly the behavioral context annotations cannot carry.

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?

Three sentences, front-loaded with the action and return value, then the reuse constraint, then the flow requirement. No filler and each sentence carries distinct information.

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?

No output schema exists, so the description takes on the burden of describing the return value, which it does ('opaque login_id', and what is never returned). For a parameterless orchestration step that must be chained with wait_for_login, nothing essential is missing.

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?

There are zero parameters, so the baseline is 4. The description correctly mentions the single output (login_id) but has no parameter-level detail to add, and none is needed.

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 ('Start official website login on this computer') plus the concrete artifact produced ('return an opaque login_id'). It also disambiguates from other login-flow siblings by noting that it reuses an active attempt rather than opening a new page.

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 routes the agent downstream: 'call wait_for_login until saved or a terminal outcome, then verify status/balance and resume the original request.' It states both the required follow-up tool and the sequencing condition, so the agent knows how to use this in context rather than in isolation.

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