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

Annotations already cover safety (readOnlyHint=true, openWorldHint=false), so the bar is lower; the description still adds that the result is exhaustive ("every helper") and that each entry carries a call signature and purpose. That is real return-shape information absent from the structured fields. No auth, cost, or pagination caveats are mentioned, but none are plausibly needed for a static catalog.

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 short sentences, front-loaded with what is returned, followed by when it is useful and what each item contains. No filler, no repetition of the title.

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 zero parameters and no output schema, the description carries the return-value burden and does so at a high level (helpers with signatures and purpose). Only the concrete container format (e.g., array vs. JSON object) is left implicit, which is minor for a no-argument lookup.

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?

The tool takes no parameters, so the baseline is 4 and there is nothing further for the description to disambiguate. Nothing in the text misrepresents the empty input 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 (returns/lists) and resource (Handlebars helpers), and scopes exactly where those helpers apply: code-template HTML/CSS and field-rule Template expressions. No sibling tool offers an equivalent enumeration, so an agent can identify it immediately.

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?

"Useful when drafting a new template or transformation rule" gives a clear positive trigger tied to the sibling create_code_template / update_field_rules workflow. It stops short of explicit exclusions or naming an alternative, but no plausible alternative exists in the sibling list.

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