list_templates

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

Annotations already declare this as a safe read-only operation (readOnlyHint=true, destructiveHint=false). The description adds valuable context beyond annotations by specifying the exact filesystem location (~/.config/email-mcp/templates/) and the placeholder syntax ({{variable}}), which helps the agent know what to expect when invoking the tool.

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, dense sentence that conveys both the action and the relevant details (location, format) without any wasted words. It is front-loaded with the core purpose and then provides supporting context.

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 list tool with no output schema, the description sufficiently covers what the tool does and what the templates are. It could potentially describe the return format (e.g., template names or paths), but the given details are adequate for an agent to select and call the tool correctly.

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 description provides all needed context about the data source. With 0 parameters, the schema already covers everything; the description's mention of the template location adds meaning beyond the empty schema.

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 uses the specific verb 'list' with the resource 'email templates', clearly distinguishing this from sibling tools like list_accounts or list_mailboxes. It also specifies the scope ('all available') and adds detail about the template format, making the purpose unambiguous.

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 clearly implies this tool is used to discover available templates (e.g., before applying one), but it does not explicitly mention alternatives or when not to use it. The context about TOML files and placeholders provides useful background that helps the agent understand the tool's role.

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