ddb_login

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

It discloses that a Chrome window opens and closes automatically once the session is saved, which is a behavioral trait beyond the annotations. This helps the agent anticipate user interaction and the tool's lifecycle, adding value beyond the openWorldHint and idempotentHint.

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 two sentences, front-loaded with the primary action. Every sentence contributes essential information: the action itself, the browser behavior, and the resulting effect on other tools. No unnecessary words.

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, no-output-schema tool, the description covers the entire workflow: launching a browser, user login, automatic closure, and the benefit for subsequent character tools. The annotations supply safety details, so 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?

The tool has zero parameters, and the schema is empty. The description appropriately focuses on behavior rather than parameters. Since there are no parameters to explain, the baseline score of 4 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 opens with a specific imperative: 'Launch a browser and log into D&D Beyond.' This clearly identifies the tool's action and resource, distinguishing it from sibling tools like ddb_list_characters or ddb_get_character. The added detail about browser behavior reinforces the unique purpose.

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 states that after login, 'character tools work without any browser,' which implies the tool is a prerequisite for using character-related tools. It provides clear context but does not explicitly mention alternatives or when not to use this tool, though for a login tool such guidance is less critical.

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