pyfastmail-mcp

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

No annotations are provided, so the description carries full burden. It mentions the tool verifies connectivity and returns account info, but lacks details on behavioral traits like authentication requirements, rate limits, error conditions, or what specific account info is returned. For a tool with zero annotation coverage, this leaves significant gaps in understanding its operation.

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, efficient sentence that directly states the tool's purpose without any fluff. It's front-loaded with the core action ('verify connectivity') and includes the essential outcome ('return account info'). Every word earns its place.

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 simplicity (0 parameters, output schema exists), the description is reasonably complete. It explains what the tool does at a high level. However, with no annotations and behavioral gaps (like auth needs or error handling), it could be more comprehensive despite the output schema covering return values.

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 0 parameters with 100% schema description coverage. The description appropriately doesn't waste space explaining non-existent parameters. It focuses on the tool's purpose rather than parameter details, which is correct for a parameterless tool.

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 tool's purpose with specific verbs ('verify connectivity', 'return account info') and identifies the target resource (Fastmail). It distinguishes itself from siblings by focusing on system health rather than mail/calendar/contacts/files operations. However, it doesn't explicitly contrast with potential alternative health-check 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 implies usage context (verifying connectivity to Fastmail), suggesting this tool should be used when checking if the service is accessible. However, it provides no explicit guidance on when to use this versus alternatives, nor does it mention prerequisites or exclusions. The implied context is helpful but incomplete.

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