fidelity_login

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

No annotations exist, and the description carries the full burden well: it discloses the visible UI, the up-to-10-minute wait, that the session is saved afterward, and the security guarantee that no credentials are requested or typed. This is exactly the behavioral context an agent needs before invoking a blocking, human-in-the-loop tool.

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 short sentences, front-loaded with what happens, followed by the wait/save behavior and the call-once constraint. Every sentence adds distinct information with no repetition.

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 zero-param, no-output-schema tool, the description covers trigger, duration, side effect, and safety. The only minor gap is what the caller should do if the 10-minute wait elapses without a completed login, but this is a small omission.

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 tool takes zero parameters, so per the rubric the baseline is 4. The description correctly implies there is nothing to supply, though it does not explicitly say 'no arguments required'.

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 (open a visible browser window on Fidelity's sign-in page) plus the scope that matters: the USER completes login and 2FA. It is clearly distinguishable from siblings like fidelity_status or fidelity_get_accounts, which never open a browser.

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?

Gives an explicit trigger ('Call once when a tool reports the session expired') and an explicit anti-pattern ('don't retry in a loop'). The agent knows both when to call it and when not to, without inferring from sibling names.

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