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

Annotations only declare it as a non-read-only, non-destructive, closed-world mutation; the description adds real behavioral content on top: a 480-character cap for texts, the requirement to preserve {pay_link} where the default has it, and the 'show the owner first' confirmation step. It does not describe what the call returns or what happens if constraints are violated, keeping it below 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?

The prerequisite is front-loaded and every clause carries information; nothing is padding. However the merge-field inventory is written as an unpunctuated run of tokens with a parenthetical invite exception, which is dense enough to risk misparsing compared with a short list format.

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 5-parameter mutation with no output schema, the description covers the prerequisite, content constraints, kind/channel coupling, and the review step, which is most of what an agent needs to call it correctly. Minor omissions remain around failure behavior and the optional subject field for email templates.

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 already 100%, so the baseline is 3, but the description adds genuine meaning: it maps kind values to channel ('final is email, the rest text'), constrains body length and required placeholders, and lists which merge fields each template kind may use. That goes meaningfully beyond the schema's generic strings.

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 a specific verb ('Reword') on a clearly scoped resource ('a collection reminder or the onboarding invite') and enumerates the template kinds. It is easy to separate from list_message_templates or reset_message_template by intent, though it never names those siblings to make the distinction explicit.

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?

It gives a concrete precondition ('Needs the workspace_key from create_workspace') and a workflow rule ('Show the owner the wording first'), which tells the agent not to just apply the change blindly. There is no explicit when-not guidance or pointer to reset_message_template for reverting, so it falls short of full alternative routing.

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