MCP Email Service

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It states the action ('List all configured email accounts') but doesn't describe what 'configured' means, whether this includes disabled or inactive accounts, the format of the returned data, pagination behavior, or any authentication requirements. For a tool with zero annotation coverage, this leaves significant behavioral gaps.

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 a single, clear sentence: 'List all configured email accounts'. It is front-loaded with the core action and resource, with no unnecessary words or structural fluff. Every word earns its place by specifying the verb, scope ('all'), and target resource.

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?

Given the tool's low complexity (0 parameters, no output schema, no annotations), the description is minimally adequate. It states what the tool does but lacks details on behavior, output format, or usage context. For a simple list operation, this might suffice, but the absence of any behavioral or output information leaves room for improvement in 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 0 parameters with 100% description coverage, so no parameter documentation is needed. The description appropriately doesn't mention parameters, as there are none to explain. This meets the baseline for tools with no parameters, where the description focuses on the tool's purpose rather than input details.

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 'List all configured email accounts' clearly states the verb ('List') and resource ('configured email accounts'), making the tool's purpose immediately understandable. It doesn't explicitly differentiate from siblings like 'list_emails' or 'list_folders', but the resource specificity ('accounts' vs 'emails'/'folders') provides implicit distinction. The description is not tautological with the name 'list_accounts' as it adds 'configured email' context.

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 provides no guidance on when to use this tool versus alternatives. With siblings like 'list_emails', 'list_folders', and 'get_contact_timeline', there's no indication of when listing accounts is appropriate versus listing other resources. No prerequisites, exclusions, or comparative context are mentioned, leaving usage entirely implicit.

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