get_account_info

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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the description does not need to repeat those. The description adds error behavior ('returns an error if API key is invalid') and return value details. However, it fails to explain the purpose of the 'account' parameter, leaving a gap in behavioral understanding. The parameter is undocumented despite being present in the schema.

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 well-structured with a clear purpose sentence, usage guidelines, return details, and an example. It is mostly concise, though the return field listing could be slightly more streamlined. Every sentence adds value.

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 read-only info tool with one optional parameter, the description covers return types and usage guidelines well. However, the missing documentation of the 'account' parameter makes it incomplete. The presence of an output schema (not shown) likely covers return structure, but the parameter gap reduces completeness.

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 input schema has one parameter 'account' with no description (0% schema coverage). The tool description does not explain what this parameter does; it only shows an example call without arguments. The parameter's role (e.g., specifying a different account) is entirely unclear, providing no value beyond the schema itself.

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 it retrieves Mailchimp account details (name, contact info, total subscribers, industry benchmarks). The verb 'Retrieve' and resource 'Mailchimp account details' are specific. It distinguishes from sibling tools like ping (health check) and list_audiences (per-audience stats).

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?

Explicit guidance provided: 'Use this to verify API connectivity or inspect account-level metrics. Typically the first call in a workflow. Do not use this as a health check; use ping instead... Use list_audiences to get per-audience stats.' Alternatives and when-not-to-use are clearly stated.

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