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

Annotations already establish readOnlyHint=true, destructiveHint=false, and openWorldHint=false, so the safety profile is covered. The description adds a genuinely useful behavioral fact not available elsewhere: the fixed 100-per-page pagination contract and how to continue. It says nothing about ordering, rate limits, or total counts, so the addition is modest.

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?

Two short sentences, zero filler, with the resource identified first and the pagination rule second. Nothing is redundant with the title or the schema descriptions.

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 read-only list tool with a fully described five-parameter schema and no output schema, the description covers the one non-obvious thing (pagination). Minor gaps remain: the response shape beyond next_cursor and whether the purpose parameter is mandatory in practice are not addressed.

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%, so the baseline is 3 and the schema already documents limit, cursor, status, channel, and purpose. The description adds only the paging contract (100 max, feed page_token forward); it says nothing about valid status values or how the filters compose.

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 states a specific verb and resource ("Lists ... message templates") and names the channels covered (WhatsApp/SMS/email), which is far more than a restatement of the name. It does not explicitly distinguish itself from other list_* siblings or from desk-related reads, but its subject matter is clear enough to identify without opening the schema.

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 only procedural guidance is pagination mechanics ('Pagination: pass page_token as page_token'). There is no statement of when an agent should choose this tool versus other listing tools, no prerequisite conditions, and no note on when to filter by channel/status instead of paging everything.

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