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

Annotations already declare readOnly/idempotent/non-destructive/openWorld, so the safety profile is covered. The description adds value beyond that: it states the auth requirement ('Needs read') and scopes the samples output to 'tone, length and language only', which is useful behavioral context. It omits pagination behavior for 'continue', keeping it from a 5.

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?

Three tight sentences with the primary listing behavior front-loaded and no filler. The terse phrasing is efficient, though the quoted internal name 'mailmcp-templates' is unexplained and slightly opaque.

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?

With no output schema, the description carries some burden for describing what comes back; it covers templates and the samples style profile reasonably but does not explain the template structure, pagination via 'continue', or how list-mode and samples-mode relate. Adequate but with clear gaps for a 7-parameter tool.

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 coverage is 71% and the schema already documents n, to, continue, and max_chars. The description adds meaning for samples=true and for retrieving one template by name, but does not explain the other parameters beyond what the schema provides, so the baseline 3 is appropriate.

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 gives a specific verb (lists) plus resource (templates in 'mailmcp-templates') and a second mode ('one in full by name'), and clarifies that samples=true returns a style profile rather than templates. It does not name or contrast with any sibling such as save_template, so it stops short of 5.

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?

'samples=true returns...' implies the condition for the alternate mode, and 'Needs read; every plan' hints at when it is expected to be consulted. However, there is no explicit when-not guidance and no routing to alternatives like save_template, leaving usage largely inferred.

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