Log In to ZeroHrs

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

The description goes beyond the all-false annotations by disclosing that the tool initiates a browser-based sign-in, implying a side-effecting and non-idempotent action. The critical behavioral trait "No session token passes through Codex chat" is a valuable privacy disclosure not captured in the annotations. It does not fully explain session lifecycle or whether user interaction is required, but the core behavior is clearly communicated.

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 description is exactly two sentences with no filler. The primary action is front-loaded, and the second sentence adds a critical security justification without redundancy. Every word contributes to the agent's understanding.

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-parameter tool, the description covers the essential behavior and the important privacy guarantee. The main gaps are the lack of any mention that login is a prerequisite for authenticated sibling operations and no indication of what response or confirmation the agent should expect, especially since there is no output schema. These are minor omissions for such a simple action.

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 has zero parameters and the schema description coverage is 100%, so there is nothing for the description to add about parameters. The baseline of 4 applies because no parameter documentation is needed. The description's reference to "private browser sign-in" provides action-level context rather than parameter semantics.

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 clearly states a specific verb and resource: "Start a private browser sign-in for this local MCP." It also adds a distinguishing security detail — "No session token passes through Codex chat" — which sets this tool apart from the data-oriented sibling tools. Even without the tool name, an agent would understand exactly what action this performs.

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 implies this should be used when authentication for the local MCP is needed, and the tool name reinforces that. However, it does not explicitly state when to use it, when not to use it, or how it relates to the sibling disconnect tool. The "for this local MCP" phrasing provides context, but no explicit exclusions or alternatives are given.

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