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

Annotations already declare readOnly, idempotent, non-destructive, closed-world behavior, so the safety profile is covered. The description adds valuable context beyond that by disclosing what the call returns (name, body, subject) even though no output schema exists, and by noting the id shortcut for single retrieval.

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?

A single sentence that front-loads the primary listing behavior, then appends the fetch-one variant. Every clause carries information; nothing is redundant or padded.

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 two-optional-parameter read tool with annotations covering safety and no output schema, the description supplies the return-field summary an agent would otherwise lack. Only minor gap: no mention of ordering, pagination, or result size limits.

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 description coverage is 100%: both `id` ('Returns that one template') and `type` ('Omit for both') are already documented in the schema. The description essentially restates these, adding no syntax, format, or edge-case detail beyond the 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?

States a specific verb (list) and resource (SMS/email templates) plus the fields returned (name, body, subject), and covers the alternate fetch-one mode via id. Clear enough to distinguish from most siblings, though it never names templates_manage as the write counterpart.

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?

Usage is only implied: 'pass id to fetch one' tells the agent about the single-item mode, but there is no explicit statement of when to call this versus templates_manage, nor any prerequisite or exclusion guidance.

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