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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, covering the safety profile. The description adds context about the content ('full instructions and accounting guidance') but does not disclose additional behavioral details beyond annotations, so a 3 is appropriate.

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?

A single, front-loaded sentence with zero waste. It states the action, the resource, and the prerequisite in a compact form. Excellent structure.

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 simple read tool with one parameter and safety annotations, the description is nearly complete. It lacks explicit return-value details, but given no output schema and the tool's straightforward nature, it provides sufficient context for correct invocation. A 4 is warranted.

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% for the single slug parameter, but the description adds meaningful context by specifying the slug must come from search_help_articles. This goes beyond the schema's simple 'Help article slug' description, enhancing the parameter's semantic meaning.

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 the verb 'Open' and the resource 'full instructions and accounting guidance in one help article', and distinguishes it from search_help_articles by specifying it uses the slug returned by that search. It is specific and unambiguous, separating it from sibling tools.

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 instructs to use the slug returned by search_help_articles, establishing a clear prerequisite and workflow. It tells the agent when to use this tool (after obtaining a slug) and implies not to call it without one, effectively differentiating from the search tool.

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