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

With no annotations, the description carries the burden and does well: it discloses overwrite semantics ('Replaces any earlier template for that kind'), immutability of the link and sender line, and a validation rule on the link placeholder. It omits permission/auth requirements and shop scoping, which keeps it short of 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 dense sentences, front-loaded with the action, then constraints, then side effects. No filler, though the brand reference 'Doing Work' mid-sentence is slightly awkward and could be trimmed.

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?

An output schema exists, so return values need not be described. For a mutation tool with zero annotations, the description covers the important hazards (overwrite, unchangeable fields, placeholder validation); only scope/permissions and the valid kind values remain unexplained.

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 0%, so the description must compensate. It gives real meaning to 'kind' and ties each link placeholder to a kind, but never enumerates the three allowed kinds, never explains shop_id, and says nothing about the subject/body length limits in 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 and resource: set the subject and body wording for one kind of automatic customer email. This clearly separates it from listing (messages_templates) or resetting templates, though it never names those siblings explicitly to route the agent.

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 implied by the constraints (use the kind's placeholders; the link placeholder must appear exactly once) rather than stated as when-to-use. There is no explicit guidance on when to choose this over messages_previewTemplate or messages_resetTemplate, which are the natural alternatives in the sibling set.

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